Economic value (EV), sensitivity of EV and relative economic importance of milk yield (MY), age a... more Economic value (EV), sensitivity of EV and relative economic importance of milk yield (MY), age at rst calving (AFC), calving interval (CI) and herd life (HL) traits were estimated for smallholder dairy cattle production in the central part of Ethiopia. The data on biological and economic parameters were collected using household interview and group discussions methods participating 238 farmers who had crossbred dairy cattle. Bio-economic model was used to calculate EV, sensitivity of EV and relative importance of EV. Cost of animal feed takes the highest share which accounted 81.35% of the total expenditure. The overall average pro t per farmers expressed in Ethiopia currency (ETB, 1 US-$ = 39.55696 ETB) was 72,458.10 ± 5068 per year. Pro tability of crossbred dairy cattle was signi cantly varied (p < 0.05) between zones. Economic value estimated for MY, AFC, CI and HL in ETB were 13.38/kg,-16.19/day,-33.58/day and 79.55/day. The associated EV per additive standard deviation were 6083.62,-1311.59,-1271.05 and 117.73 ETB for MY, AFC, CI and HL, respectively. Analysis of sensitivity to scenario change (± 20%) showed that milk price had positive association with pro t and EV, whereas feed price has inversely in uenced both pro t and EV. The pro t obtained by farmers was altered by ± 29.08% and ± 12.31% as milk price and feed price uctuated by ± 20%, respectively. Similarly, the EV of MY was changed by ± 20% with change in milk price and ± 7% with feed price. Scenario change in feed price (± 20%) has also caused ± 13.63% change on EV for AFC and ± 17.58% for CI. It can be noted that pro t and EV of the traits were less sensitive to the change in price of milk, feed and labor. In general, the results of EV and pro tability were encouraging for dairy farmers and the estimates can be used as an input for development of breeding program in the study area.
Variances, heritabilities, genetic and phenotypic correlations were estimated for lactation milk ... more Variances, heritabilities, genetic and phenotypic correlations were estimated for lactation milk yield and lactation length traits in the first five lactations. The data set comprised 1809 first, 1411 second, 974 third, 705 fourth and 509 fifth lactation records of crossbred dairy cows. multivariate animal model that included breed and year as fixed effects and animal and error as random effects were applied. There were larger residual variances observed across lactations in both lactation milk yield and lactation length traits. The residual variances also increased in advanced lactation for both traits. Heritability across lactations for lactation milk yield were in the range of 0.11 to 0.35. Highest heritability (0.35) was observed at first lactation but declined then after. Mean estimation of heritability for lactation length in the five consecutive lactations were also found in the range of 0.035 to 0.401. Heritability of lactation length shows decreasing trend from first to third lactations. However, highest heritability (0.40) was found at fourth lactation which implies that presence of sufficient additive genetic variance. Estimated genetic correlations of first lactation milk yield to its corresponding lactation numbers were greater than 0.80 shows that the extent of common genes were large while phenotypic correlations were medium values within the range of 0.40 to 0.67. For lactation length, the genetic correlations between the different lactations were ranged from negative (-0.45) to 0.88. On the other hand, phenotypic correlations of lactation length in all lactations were positive values but lower in the range 0.03 to 0.39 which shows little relationship of phenotypic measurements among lactations. Results suggest that difference between variances, heritabilities as well as genetic and phenotypic correlations from multivariate analyses, each lactation number of lactation milk yield and lactation length should be assumed as separate traits. different lactations are not influenced by the same set of genes and environments.
Genetic parameters of reproductive traits of dairy cows can be evaluated by considering it as the... more Genetic parameters of reproductive traits of dairy cows can be evaluated by considering it as the same trait over the calving numbers of a given animal or by treating reproductive performances over calving numbers as different traits. The objectives of this study were to estimate variances, heritabilities genetic as well as phenotypic correlations of some reproductive (calving interval, CI and service per conception, SPC) traits of Jersey cows during their first, second, third, fourth and fifth calving/lactation numbers in Ethiopia considering each calving number as separate trait. Genetic parameters were estimated using multi-variate analysis via AI-REML algorism of the Wombat software. The pedigree file which used to compute the numerator relationship matrix were 782 and 1061, 602 and 787, 458 and 604, 368 and 455 and, 277 and 366 animals for first, second, third, fourth and fifth calving numbers of CI and SPC traits, respectively. Year as a fixed effect and animal and error/residual as random effects were assigned in the model of analysis. The analyzed results showed that higher additive, residual and phenotypic variances of calving interval (CI) were found at the third calving number. For service per conception (SPC), the variances were increased across calving numbers. The estimated heritabilities of CI in the five consecutive calving numbers were 0.15, 0.05, 0.23, 0.22 and 0.08, respectively somewhat higher than the reviewed literature reports. For SPC, the estimates were not different from zero but slightly increased across calving numbers with the values of 0.003, 0.006, 0.01, 0.016 and 0.02, respectively which were lower than the reviewed literature results. Genetic correlations of CI in first and fourth, first and fifth, second and third and, fourth and fifth calving numbers were higher (0.73-0.99) than the other respective calving numbers (-0.33-0.14) whereas, the phenotypic correlations were tended to be of close to very low and some negative values (-0.05-0.19). On the other hand, there were great genetic (0.98-0.99) and phenotypic (0.96-0.99) associations among calving numbers of SPC trait.
Online Journal of Animal and Feed Research, Jul 28, 2021
The objective of this study was to estimate methane (CH4) emission factor from enteric fermentati... more The objective of this study was to estimate methane (CH4) emission factor from enteric fermentation and manure management in indigenous cattle in Ethiopian highland using intergovernmental panel on climate change (IPCC) tier 2 methodologies. A survey was conducted in 2018 using questionnaire regarding cattle management, feed and feeding system on 50 smallholder farmers in central Ethiopia. Information was also collected from literature and contact with federal and regional research institutions. This information was used as input in the IPCC tier 2 methodologies for estimation of CH4 emission factors for eight cattle sub-categories. Results indicated that enteric CH4 emission factors were estimated to be 65, 49, 37, 56, 66, 58, 63 and 11 for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. Manure management CH4 emission factors were 4.97, 3.77, 2.86, 4.33, 5.06, 4.47, 4.88 and 1.71 kg/head/year for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. The present estimate on enteric CH4 emission factor using tier 2 methodologies in present study ranged from 11 to 66 kg per head per year while manure management CH4 emission factor ranged from 1.71 to 5 kg per head per year. These values are higher than the IPCC 2006 tier 1 default values for African region. However, present work's estimates are within a range of literature reports for other cattle in different countries. Further research is required to improve emission factors estimates using primary data on live weight, animal performance and feed characterization.
Ethiopian Journal of Agricultural Sciences, Apr 25, 2020
This study was conducted to evaluate the productive performances of crossbred dairy cattle at Hol... more This study was conducted to evaluate the productive performances of crossbred dairy cattle at Holetta agricultural research center's dairy farm. A total of 6685 performance records were used and analyzed to determine the effect of period of calving, season of calving, parity and genetic group. Parameters used as indicator of productive performances were lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL). The GLM procedure of SAS 2004 was used for analysis. The overall least square means and standard errors for Lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL) were 2204.05 ± 21.12 kg, 6.88 ± 0.05 kg and 326.69 ± 2.03 days, respectively. Result of fixed effect analysis indicated that calving period, genetic group and parity were significantly (p<0.001) influenced all productive traits. LMY, DMY, and LL were sensitive to seasonal variation. Comparisons among the crosses revealed a clear-cut difference among the genetic groups. Milk production in the first generation crosses increased more compared to second generations. There were marked decline in performance among 50% F 1 (Borena dam x Holstein Friesian sire), F 2 (F 1 dam x F 1 sire) and F 3 (F 2 dam x F 2 sire) from 2203kg of milk to 1697 and 1522 kg, respectively. The 75% first generation was superior LMY compared with other genetic groups and produced about 34.2 %, 74.3%, 94.3% and 45.9% more milk than 50% F 1, F 2, F 3 and 75% second generations, respectively. The higher milk yield of 75% first generation and 50% F 1 crosses from other genetic groups could be associated with higher heterosis effect in F 1 , higher milk gene in 75% and longer lactation length. Based on the productive performances evaluation, the results of LMY, DMY, and LL for high grade (75% first generation) in the present study revealed that performances were continued to increase with increasing proportion of exotic gene.
Journal of Dairying, Foods & Home Sciences, Mar 14, 2020
This study was aimed to generate information on variance components and the resulting genetic par... more This study was aimed to generate information on variance components and the resulting genetic parameters (heritability, repeatability, genetic and phenotypic correlations and genetic trends) of some economic traits of Borena and its crosses with Holstein Friesian dairy cattle maintained at Holetta agricultural research center dairy farm. Traits studied were age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). Overall, 11331 dairy cattle reproductive performance records were used for the study. WOMBAT, which is a software package for quantitative genetic analysis of continuous traits, fitting a linear, mixed model; estimates of covariance components and the resulting genetic parameters were employed and obtained. Heritability values of reproductive traits were from very low (0.071, 0.082 and 0.012) for CI, DO and NSC to moderate (0.3 and 0.22) for AFC and AFS traits. Repeatability estimate for CI, DO and NSC were low (0.17, 0.17 and 0.129). Strong and positive genetic correlation (0.98) was appeared between AFS and AFC traits. Negative genetic correlations were observed between AFS and DO (-0.001), AFC and DO (-0.05), AFS and NSC (-0.022), AFC and NSC (-0.29) and CI and NSC (-0.31). AFS were negative phenotypic correlation with CI, DO and NSC. Similarly, AFC was negative phenotypic correlation with CI and DO. Low phenotypic correlation was observed between AFC and NSC, CI and DO, CI and NSC and, DO and NSC. Strong and positive phenotypic correlation was appeared between AFS and AFC. The regression coefficient of mean breeding value for NSC, CI, DO, AFC and AFS on year of birth were-0.0066x+13.25 times/year,-1.19x+2387.4 days/year,-1.23x+2445.6 days/year, 0.2x-410 months/year and 0.48x-980 months/ year, respectively.
Journal of Dairying, Foods & Home Sciences, Sep 22, 2021
Background: The effect of non-genetic factors including feeding, management, climate, calving yea... more Background: The effect of non-genetic factors including feeding, management, climate, calving year, season and others on animal production improvement has attracted considerable attention in recent years. In addition to improving animal genetics, the importance of optimum environmental conditions in enhancing animal production is recognized. Methods: Data collected from 2008 to 2018 on 2036 records from crossbreeding dairy cattle herd at Holeta Agricultural Research Center were analyzed to evaluate the genetic and non-genetic environmental effect on lactation milk yield (LMY), lactation length (LL) and calving interval (CI). The fixed effect used in the data analysis were breed group, parity, years group of calving and seasons of calving. GLM procedure of SAS was used to analyze the data. Result: Results of data analysis indicated that breed group and year group of calving had a significant (P<0.05) effect on LMY, LL and CI. Parity significantly (P<0.05) affected LMY and CI but had no significant effects on LL. W hile, season of calving had no significant influence on all traits. Least square mean LMY was significantly (p<0.05) highest (3191 kg) for 75% first generation breed group and significantly (P<0.05) lowest for pure Ethiopian Borena breed (124 kg LMY). Mean LL was significantly (p<0.05) highest (354 days) for 75% first generation breed group and significantly (P<0.05) lowest for pure Ethiopian Borena breed (178 days). Least square mean CI was significantly (p<0.05) longest (477 days) for 75% first generation breed group and significantly (P<0.05) shortest (422 days) for 75% inter se mated breed group. Among 75% crosses, the 75% inter se mated breed group had lower LMY (2553 kg) and shorter CI (422 days) compared to 75% first generation breed group. The decline in LMY and CI for 75% inter se mated breed group by 637 kg (25%) and 54 days (13%), respectively compared to 75% first generation, which can be attributed to recombination effect.
Abstract Crossbreeding for improving milk yield and reproductive performances had started and imp... more Abstract Crossbreeding for improving milk yield and reproductive performances had started and implemented been long in Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from 1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and 1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50% F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit their maximum potentials because animals are subjected to different environmental effects.
Annals of environmental science and toxicology, Mar 12, 2022
Aims: The livestock production system contributes to global climate change directly through the p... more Aims: The livestock production system contributes to global climate change directly through the production of methane (CH 4) from enteric fermentation, CH 4 and nitrous oxide (N 2 O) from manure management. Enteric CH 4 emission from livestock is the major contributor to greenhouse gas (GHG) emission from livestock in Ethiopia. National inventory and reporting of enteric CH 4 emission in cattle species in Ethiopia are based on default emission factor (tier 1 methodology) developed by Intergovernmental Panel on Climate Change (IPCC). These enteric CH 4 emissions are infl uenced by different factors such as livestock feed characteristics, livestock management, and livestock production and productivity. Hence, its estimation requires accurate data specifi c to the condition of the livestock production system in the country. The objective of this study was to estimate enteric CH 4 emission from cattle species in Ethiopia. Methodology: Enteric CH 4 emission was estimated using IPCC tier 2 methods using input data collected through survey and literature data on livestock and feed characteristics in Ethiopia. Results: Results indicated that enteric CH 4 emission factors among indigenous cattle were 30.27, 18.52, 31.55, 29.82, 32.48, and 12.60 kg per head per year for matured females >2 years old, females 1-2 years, bullocks/oxen, breeding bulls >2 years old, males 1-2 years and calves <1 year's old, respectively. Among crossbred dairy cattle, enteric CH 4 emission factors were found to be 36.21, 19.98, 27.90, 25.51, 5.45 kg per head per year for matured females >2 years, females 1-2 years, matured males >2 years, males 1-2 years and calves <1 year's age, respectively. The weighted average CH 4 emission factor for indigenous cattle and crossbred dairy cattle were 26 and 30.71kg/head/year, respectively. Conclusion: Enteric CH 4 emission factors for nondairy indigenous and crossbred cattle using IPCC tier 2 methodology were lower when compared to IPCC tier 1 estimate. Our study recommends IPCC tier 2 methodology, for national enteric CH 4 emission inventory and reporting for cattle species in Ethiopia. The present study was based on limited survey and published data, uncertainties may have presented with, some of production and performance data. Further research is required to estimate enteric CH 4 emission using more detailed cattle production and feed characterization data.
Genetic and phenotypic correlations for reproductive and milk production traits were estimated by... more Genetic and phenotypic correlations for reproductive and milk production traits were estimated by multitrait analysis of WOMBAT software. Total of 14222 crossbred dairy cows performance records collected from Holetta dairy research farm span over 43 years (1974-2017) were used for this study. Five reproductive; age at first calving (AFC), age at first service (AFS), calving interval (CI), days open (DO) and number of service per conception (NSC) and three-milk production; lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL) traits were included for estimation. The result of present study revealed that the genetic correlations among reproductive traits were varied from-0.31±0.08 to 0.98±0.03 while phenotypic correlations were ranged from-0.03±0.001 to 0.84±0.04. Strong positive genetic and phenotypic correlations were found between AFS and AFC traits (0.98±0.03) and (0.84±0.04), respectively. For milk production traits, the genetic correlations were ranged from 0.11±0.03 to 0.77±0.12 while phenotypic correlations were in the lower range of 0.07±0.02 to 0.36±0.07. Higher genetic correlations were observed between LMY and LL (0.77±0.12). The genetic correlations among reproductive and milk production traits were also varied from-0.55±0.04 to 0.79±0.07 while phenotypic correlations were ranged from-0.55±0.22 to 0.32±0.10. The higher genetic correlation was between CI and LL (0.79±0.07). The correlation between DMY and AFC (0.32±0.10) was recorded as higher phenotypically. The positive genetic correlations among traits indicates that effective selection of one trait might be improved the other and would be given the chance of broader selection of traits in the breeding goal. Therefore, to improve genetic progress and breeding efficiency of crossbred dairy cows in the research farm, estimation and selection of correlated traits should be done periodically. HIGHLIGHTS m Milk yield and reproductive traits are complex relationship. m This relationship can be depend on genetic and environmental variabilities. m This study was conducted to know the correlation among reproductive and milk production traits and the results are summarized in this paper.
Global Journal of Animal Scientific Research, Dec 3, 2020
The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lact... more The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lactation and reproductive performance of dairy cattle by using WOMBAT software fitted to mixed animal model evaluation method. The performance records of 851 crossbred dairy cows, daughters of 98 sires (AI semen or bulls) were collected from the pedigree sheets at the research farm. Sires with two and more daughters were included in the data. The source of Sires (semen) were worldwide sire (WWS), Western Asia imported and domestic semen source. The traits studied were lactation milk yield (LMY), daily milk yield (DMY), lactation length (LL), age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). From the analysis, the estimated average sirebreeding value for LMY was 7.51 kg, which varied from 663.82 kg below the average to 1055.19 kg above the average. Average estimated sire-breeding value for DMY was 0.06 in the range of 1.22 kg below the average to 2.27 kg above the average breeding value. For LL, the estimated difference of sire breeding value was 97 days ranges from 49.8 days below the average to 47 days above the average. The sire breeding value of AFS trait was-0.71 days ranges from 179 days below the average to 161 days above the average. Sire-breeding value of AFC trait was-0.66 days estimated from 257 days below the average to 366 days above the average. Average sire breeding value for CI was-1.87 days ranges from 50 days below the average to 39 days above Kefale Getahun GLOBAL JOURNAL OF ANIMAL SCIENTIFIC RESEARCH, 8(3), 113-126 Page114 the average. For DO, it was-1.81 days ranged from 56 days below the average to 44 days above the average. Sire breeding value for NSC was varied from 0.02 below the average to 0.02 above the average.
Global Journal of Animal Scientific Research, Dec 3, 2020
The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lact... more The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lactation and reproductive performance of dairy cattle by using WOMBAT software fitted to mixed animal model evaluation method. The performance records of 851 crossbred dairy cows, daughters of 98 sires (AI semen or bulls) were collected from the pedigree sheets at the research farm. Sires with two and more daughters were included in the data. The source of Sires (semen) were worldwide sire (WWS), Western Asia imported and domestic semen source. The traits studied were lactation milk yield (LMY), daily milk yield (DMY), lactation length (LL), age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). From the analysis, the estimated average sirebreeding value for LMY was 7.51 kg, which varied from 663.82 kg below the average to 1055.19 kg above the average. Average estimated sire-breeding value for DMY was 0.06 in the range of 1.22 kg below the average to 2.27 kg above the average breeding value. For LL, the estimated difference of sire breeding value was 97 days ranges from 49.8 days below the average to 47 days above the average. The sire breeding value of AFS trait was-0.71 days ranges from 179 days below the average to 161 days above the average. Sire-breeding value of AFC trait was-0.66 days estimated from 257 days below the average to 366 days above the average. Average sire breeding value for CI was-1.87 days ranges from 50 days below the average to 39 days above Kefale Getahun GLOBAL JOURNAL OF ANIMAL SCIENTIFIC RESEARCH, 8(3), 113-126 Page114 the average. For DO, it was-1.81 days ranged from 56 days below the average to 44 days above the average. Sire breeding value for NSC was varied from 0.02 below the average to 0.02 above the average.
Data collected from Jersey herd in the central highland environment of Ethiopia was used to estim... more Data collected from Jersey herd in the central highland environment of Ethiopia was used to estimate genetic parameter and genetic trend analysis for reproductive/fertility traits. Totally, 11,933 Jersey reproductive records recorded during the last 30 years were used for analysis. Traits studied were NSC (number of service per conception), DO (days open), CI (calving interval), AFC (age at first calving) and AFS (age at first service). Genetic and phenotypic parameters (heritability, repeatability, genetic and phenotypic correlation and estimated breeding values of individual animal) were estimated by using WOMBAT software package, version (2020) fitting a multi trait animal model. Genetic and phenotypic trends were calculated by regression of average estimated breeding values/phenotypic values of each trait on birth years. The estimated heritability for NSC, DO, CI, AFC and AFS were 0.01, 0.08, 0.04, 0.09 and 0.08, respectively while the corresponding repeatability values were 0.01, 0.11 and 0.14, respectively without the estimated values of AFC and AFS. Genetic correlations were all positive and in the range from 0.11 between DO and AFC to 0.99 between DO and CI. Phenotypic correlations were also positive and ranges from 0.16 (AFS-CI) to 0.98 (AFC-AFS). Genetic trend analysis based on birth years for NSC, DO, CI, AFC and AFS were in the favorable direction and found to be-0.002,-0.82 day,-0.6 day,-0.002 month and-0.002 month, respectively whereas phenotypic trends were-0.05, 0.93 day, 0.81 day, 3.2 months and 2.4 months, respectively which are unfavorable direction and undesirable for most traits. As monitored in the present study, the reproductive/fertility performance of Jersey cows in the central highland of Ethiopia was somewhat based on genetic effects but larger undesirable environmental components for the total phenotypic value.
Background: The productivity and profitability of dairy cattle depend largely on reproductive per... more Background: The productivity and profitability of dairy cattle depend largely on reproductive performance. Thus, this study was intended to evaluate the reproductive performance of Jersey cattle raised under semi-intensive management system.Methods: A retrospective analysis consisted of data collected for the last 33 years was conducted. The fixed effects fitted were birth period, calving period, service period, birth season, calving season, service season, parity and genetic group. The general linear model procedure of SAS was used for the statistical analysis of data.Result: The overall least-square means for age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and the number of services per conception (NSPC) were 22.93±0.22 months, 32.95±0.22 months, 494.16±3.68 days, 221.09±3.73 days and 1.99±0.03, respectively. Year, season and parity had a significant effect on most of the investigated reproductive traits. Imported Jersey cows had an ex...
Abstract Crossbreeding for improving milk yield and reproductive performances had started and imp... more Abstract Crossbreeding for improving milk yield and reproductive performances had started and implemented been long in
Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the
status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different
stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia
varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from
1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station
conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first
service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and
1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive
performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein
Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50%
F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second
generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed
in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic
factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk
yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit
their maximum potentials because animals are subjected to different environmental effects.
Economic value (EV), sensitivity of EV and relative economic importance of milk yield (MY), age a... more Economic value (EV), sensitivity of EV and relative economic importance of milk yield (MY), age at rst calving (AFC), calving interval (CI) and herd life (HL) traits were estimated for smallholder dairy cattle production in the central part of Ethiopia. The data on biological and economic parameters were collected using household interview and group discussions methods participating 238 farmers who had crossbred dairy cattle. Bio-economic model was used to calculate EV, sensitivity of EV and relative importance of EV. Cost of animal feed takes the highest share which accounted 81.35% of the total expenditure. The overall average pro t per farmers expressed in Ethiopia currency (ETB, 1 US-$ = 39.55696 ETB) was 72,458.10 ± 5068 per year. Pro tability of crossbred dairy cattle was signi cantly varied (p < 0.05) between zones. Economic value estimated for MY, AFC, CI and HL in ETB were 13.38/kg,-16.19/day,-33.58/day and 79.55/day. The associated EV per additive standard deviation were 6083.62,-1311.59,-1271.05 and 117.73 ETB for MY, AFC, CI and HL, respectively. Analysis of sensitivity to scenario change (± 20%) showed that milk price had positive association with pro t and EV, whereas feed price has inversely in uenced both pro t and EV. The pro t obtained by farmers was altered by ± 29.08% and ± 12.31% as milk price and feed price uctuated by ± 20%, respectively. Similarly, the EV of MY was changed by ± 20% with change in milk price and ± 7% with feed price. Scenario change in feed price (± 20%) has also caused ± 13.63% change on EV for AFC and ± 17.58% for CI. It can be noted that pro t and EV of the traits were less sensitive to the change in price of milk, feed and labor. In general, the results of EV and pro tability were encouraging for dairy farmers and the estimates can be used as an input for development of breeding program in the study area.
Variances, heritabilities, genetic and phenotypic correlations were estimated for lactation milk ... more Variances, heritabilities, genetic and phenotypic correlations were estimated for lactation milk yield and lactation length traits in the first five lactations. The data set comprised 1809 first, 1411 second, 974 third, 705 fourth and 509 fifth lactation records of crossbred dairy cows. multivariate animal model that included breed and year as fixed effects and animal and error as random effects were applied. There were larger residual variances observed across lactations in both lactation milk yield and lactation length traits. The residual variances also increased in advanced lactation for both traits. Heritability across lactations for lactation milk yield were in the range of 0.11 to 0.35. Highest heritability (0.35) was observed at first lactation but declined then after. Mean estimation of heritability for lactation length in the five consecutive lactations were also found in the range of 0.035 to 0.401. Heritability of lactation length shows decreasing trend from first to third lactations. However, highest heritability (0.40) was found at fourth lactation which implies that presence of sufficient additive genetic variance. Estimated genetic correlations of first lactation milk yield to its corresponding lactation numbers were greater than 0.80 shows that the extent of common genes were large while phenotypic correlations were medium values within the range of 0.40 to 0.67. For lactation length, the genetic correlations between the different lactations were ranged from negative (-0.45) to 0.88. On the other hand, phenotypic correlations of lactation length in all lactations were positive values but lower in the range 0.03 to 0.39 which shows little relationship of phenotypic measurements among lactations. Results suggest that difference between variances, heritabilities as well as genetic and phenotypic correlations from multivariate analyses, each lactation number of lactation milk yield and lactation length should be assumed as separate traits. different lactations are not influenced by the same set of genes and environments.
Genetic parameters of reproductive traits of dairy cows can be evaluated by considering it as the... more Genetic parameters of reproductive traits of dairy cows can be evaluated by considering it as the same trait over the calving numbers of a given animal or by treating reproductive performances over calving numbers as different traits. The objectives of this study were to estimate variances, heritabilities genetic as well as phenotypic correlations of some reproductive (calving interval, CI and service per conception, SPC) traits of Jersey cows during their first, second, third, fourth and fifth calving/lactation numbers in Ethiopia considering each calving number as separate trait. Genetic parameters were estimated using multi-variate analysis via AI-REML algorism of the Wombat software. The pedigree file which used to compute the numerator relationship matrix were 782 and 1061, 602 and 787, 458 and 604, 368 and 455 and, 277 and 366 animals for first, second, third, fourth and fifth calving numbers of CI and SPC traits, respectively. Year as a fixed effect and animal and error/residual as random effects were assigned in the model of analysis. The analyzed results showed that higher additive, residual and phenotypic variances of calving interval (CI) were found at the third calving number. For service per conception (SPC), the variances were increased across calving numbers. The estimated heritabilities of CI in the five consecutive calving numbers were 0.15, 0.05, 0.23, 0.22 and 0.08, respectively somewhat higher than the reviewed literature reports. For SPC, the estimates were not different from zero but slightly increased across calving numbers with the values of 0.003, 0.006, 0.01, 0.016 and 0.02, respectively which were lower than the reviewed literature results. Genetic correlations of CI in first and fourth, first and fifth, second and third and, fourth and fifth calving numbers were higher (0.73-0.99) than the other respective calving numbers (-0.33-0.14) whereas, the phenotypic correlations were tended to be of close to very low and some negative values (-0.05-0.19). On the other hand, there were great genetic (0.98-0.99) and phenotypic (0.96-0.99) associations among calving numbers of SPC trait.
Online Journal of Animal and Feed Research, Jul 28, 2021
The objective of this study was to estimate methane (CH4) emission factor from enteric fermentati... more The objective of this study was to estimate methane (CH4) emission factor from enteric fermentation and manure management in indigenous cattle in Ethiopian highland using intergovernmental panel on climate change (IPCC) tier 2 methodologies. A survey was conducted in 2018 using questionnaire regarding cattle management, feed and feeding system on 50 smallholder farmers in central Ethiopia. Information was also collected from literature and contact with federal and regional research institutions. This information was used as input in the IPCC tier 2 methodologies for estimation of CH4 emission factors for eight cattle sub-categories. Results indicated that enteric CH4 emission factors were estimated to be 65, 49, 37, 56, 66, 58, 63 and 11 for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. Manure management CH4 emission factors were 4.97, 3.77, 2.86, 4.33, 5.06, 4.47, 4.88 and 1.71 kg/head/year for mature lactating cows, dry cows, heifers (2-3 years), growing females (1-2 years), draught oxen, mature breeding males, growing males (1-2 years) and calves (< 1 year), respectively. The present estimate on enteric CH4 emission factor using tier 2 methodologies in present study ranged from 11 to 66 kg per head per year while manure management CH4 emission factor ranged from 1.71 to 5 kg per head per year. These values are higher than the IPCC 2006 tier 1 default values for African region. However, present work's estimates are within a range of literature reports for other cattle in different countries. Further research is required to improve emission factors estimates using primary data on live weight, animal performance and feed characterization.
Ethiopian Journal of Agricultural Sciences, Apr 25, 2020
This study was conducted to evaluate the productive performances of crossbred dairy cattle at Hol... more This study was conducted to evaluate the productive performances of crossbred dairy cattle at Holetta agricultural research center's dairy farm. A total of 6685 performance records were used and analyzed to determine the effect of period of calving, season of calving, parity and genetic group. Parameters used as indicator of productive performances were lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL). The GLM procedure of SAS 2004 was used for analysis. The overall least square means and standard errors for Lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL) were 2204.05 ± 21.12 kg, 6.88 ± 0.05 kg and 326.69 ± 2.03 days, respectively. Result of fixed effect analysis indicated that calving period, genetic group and parity were significantly (p<0.001) influenced all productive traits. LMY, DMY, and LL were sensitive to seasonal variation. Comparisons among the crosses revealed a clear-cut difference among the genetic groups. Milk production in the first generation crosses increased more compared to second generations. There were marked decline in performance among 50% F 1 (Borena dam x Holstein Friesian sire), F 2 (F 1 dam x F 1 sire) and F 3 (F 2 dam x F 2 sire) from 2203kg of milk to 1697 and 1522 kg, respectively. The 75% first generation was superior LMY compared with other genetic groups and produced about 34.2 %, 74.3%, 94.3% and 45.9% more milk than 50% F 1, F 2, F 3 and 75% second generations, respectively. The higher milk yield of 75% first generation and 50% F 1 crosses from other genetic groups could be associated with higher heterosis effect in F 1 , higher milk gene in 75% and longer lactation length. Based on the productive performances evaluation, the results of LMY, DMY, and LL for high grade (75% first generation) in the present study revealed that performances were continued to increase with increasing proportion of exotic gene.
Journal of Dairying, Foods & Home Sciences, Mar 14, 2020
This study was aimed to generate information on variance components and the resulting genetic par... more This study was aimed to generate information on variance components and the resulting genetic parameters (heritability, repeatability, genetic and phenotypic correlations and genetic trends) of some economic traits of Borena and its crosses with Holstein Friesian dairy cattle maintained at Holetta agricultural research center dairy farm. Traits studied were age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). Overall, 11331 dairy cattle reproductive performance records were used for the study. WOMBAT, which is a software package for quantitative genetic analysis of continuous traits, fitting a linear, mixed model; estimates of covariance components and the resulting genetic parameters were employed and obtained. Heritability values of reproductive traits were from very low (0.071, 0.082 and 0.012) for CI, DO and NSC to moderate (0.3 and 0.22) for AFC and AFS traits. Repeatability estimate for CI, DO and NSC were low (0.17, 0.17 and 0.129). Strong and positive genetic correlation (0.98) was appeared between AFS and AFC traits. Negative genetic correlations were observed between AFS and DO (-0.001), AFC and DO (-0.05), AFS and NSC (-0.022), AFC and NSC (-0.29) and CI and NSC (-0.31). AFS were negative phenotypic correlation with CI, DO and NSC. Similarly, AFC was negative phenotypic correlation with CI and DO. Low phenotypic correlation was observed between AFC and NSC, CI and DO, CI and NSC and, DO and NSC. Strong and positive phenotypic correlation was appeared between AFS and AFC. The regression coefficient of mean breeding value for NSC, CI, DO, AFC and AFS on year of birth were-0.0066x+13.25 times/year,-1.19x+2387.4 days/year,-1.23x+2445.6 days/year, 0.2x-410 months/year and 0.48x-980 months/ year, respectively.
Journal of Dairying, Foods & Home Sciences, Sep 22, 2021
Background: The effect of non-genetic factors including feeding, management, climate, calving yea... more Background: The effect of non-genetic factors including feeding, management, climate, calving year, season and others on animal production improvement has attracted considerable attention in recent years. In addition to improving animal genetics, the importance of optimum environmental conditions in enhancing animal production is recognized. Methods: Data collected from 2008 to 2018 on 2036 records from crossbreeding dairy cattle herd at Holeta Agricultural Research Center were analyzed to evaluate the genetic and non-genetic environmental effect on lactation milk yield (LMY), lactation length (LL) and calving interval (CI). The fixed effect used in the data analysis were breed group, parity, years group of calving and seasons of calving. GLM procedure of SAS was used to analyze the data. Result: Results of data analysis indicated that breed group and year group of calving had a significant (P<0.05) effect on LMY, LL and CI. Parity significantly (P<0.05) affected LMY and CI but had no significant effects on LL. W hile, season of calving had no significant influence on all traits. Least square mean LMY was significantly (p<0.05) highest (3191 kg) for 75% first generation breed group and significantly (P<0.05) lowest for pure Ethiopian Borena breed (124 kg LMY). Mean LL was significantly (p<0.05) highest (354 days) for 75% first generation breed group and significantly (P<0.05) lowest for pure Ethiopian Borena breed (178 days). Least square mean CI was significantly (p<0.05) longest (477 days) for 75% first generation breed group and significantly (P<0.05) shortest (422 days) for 75% inter se mated breed group. Among 75% crosses, the 75% inter se mated breed group had lower LMY (2553 kg) and shorter CI (422 days) compared to 75% first generation breed group. The decline in LMY and CI for 75% inter se mated breed group by 637 kg (25%) and 54 days (13%), respectively compared to 75% first generation, which can be attributed to recombination effect.
Abstract Crossbreeding for improving milk yield and reproductive performances had started and imp... more Abstract Crossbreeding for improving milk yield and reproductive performances had started and implemented been long in Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from 1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and 1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50% F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit their maximum potentials because animals are subjected to different environmental effects.
Annals of environmental science and toxicology, Mar 12, 2022
Aims: The livestock production system contributes to global climate change directly through the p... more Aims: The livestock production system contributes to global climate change directly through the production of methane (CH 4) from enteric fermentation, CH 4 and nitrous oxide (N 2 O) from manure management. Enteric CH 4 emission from livestock is the major contributor to greenhouse gas (GHG) emission from livestock in Ethiopia. National inventory and reporting of enteric CH 4 emission in cattle species in Ethiopia are based on default emission factor (tier 1 methodology) developed by Intergovernmental Panel on Climate Change (IPCC). These enteric CH 4 emissions are infl uenced by different factors such as livestock feed characteristics, livestock management, and livestock production and productivity. Hence, its estimation requires accurate data specifi c to the condition of the livestock production system in the country. The objective of this study was to estimate enteric CH 4 emission from cattle species in Ethiopia. Methodology: Enteric CH 4 emission was estimated using IPCC tier 2 methods using input data collected through survey and literature data on livestock and feed characteristics in Ethiopia. Results: Results indicated that enteric CH 4 emission factors among indigenous cattle were 30.27, 18.52, 31.55, 29.82, 32.48, and 12.60 kg per head per year for matured females >2 years old, females 1-2 years, bullocks/oxen, breeding bulls >2 years old, males 1-2 years and calves <1 year's old, respectively. Among crossbred dairy cattle, enteric CH 4 emission factors were found to be 36.21, 19.98, 27.90, 25.51, 5.45 kg per head per year for matured females >2 years, females 1-2 years, matured males >2 years, males 1-2 years and calves <1 year's age, respectively. The weighted average CH 4 emission factor for indigenous cattle and crossbred dairy cattle were 26 and 30.71kg/head/year, respectively. Conclusion: Enteric CH 4 emission factors for nondairy indigenous and crossbred cattle using IPCC tier 2 methodology were lower when compared to IPCC tier 1 estimate. Our study recommends IPCC tier 2 methodology, for national enteric CH 4 emission inventory and reporting for cattle species in Ethiopia. The present study was based on limited survey and published data, uncertainties may have presented with, some of production and performance data. Further research is required to estimate enteric CH 4 emission using more detailed cattle production and feed characterization data.
Genetic and phenotypic correlations for reproductive and milk production traits were estimated by... more Genetic and phenotypic correlations for reproductive and milk production traits were estimated by multitrait analysis of WOMBAT software. Total of 14222 crossbred dairy cows performance records collected from Holetta dairy research farm span over 43 years (1974-2017) were used for this study. Five reproductive; age at first calving (AFC), age at first service (AFS), calving interval (CI), days open (DO) and number of service per conception (NSC) and three-milk production; lactation milk yield (LMY), daily milk yield (DMY) and lactation length (LL) traits were included for estimation. The result of present study revealed that the genetic correlations among reproductive traits were varied from-0.31±0.08 to 0.98±0.03 while phenotypic correlations were ranged from-0.03±0.001 to 0.84±0.04. Strong positive genetic and phenotypic correlations were found between AFS and AFC traits (0.98±0.03) and (0.84±0.04), respectively. For milk production traits, the genetic correlations were ranged from 0.11±0.03 to 0.77±0.12 while phenotypic correlations were in the lower range of 0.07±0.02 to 0.36±0.07. Higher genetic correlations were observed between LMY and LL (0.77±0.12). The genetic correlations among reproductive and milk production traits were also varied from-0.55±0.04 to 0.79±0.07 while phenotypic correlations were ranged from-0.55±0.22 to 0.32±0.10. The higher genetic correlation was between CI and LL (0.79±0.07). The correlation between DMY and AFC (0.32±0.10) was recorded as higher phenotypically. The positive genetic correlations among traits indicates that effective selection of one trait might be improved the other and would be given the chance of broader selection of traits in the breeding goal. Therefore, to improve genetic progress and breeding efficiency of crossbred dairy cows in the research farm, estimation and selection of correlated traits should be done periodically. HIGHLIGHTS m Milk yield and reproductive traits are complex relationship. m This relationship can be depend on genetic and environmental variabilities. m This study was conducted to know the correlation among reproductive and milk production traits and the results are summarized in this paper.
Global Journal of Animal Scientific Research, Dec 3, 2020
The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lact... more The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lactation and reproductive performance of dairy cattle by using WOMBAT software fitted to mixed animal model evaluation method. The performance records of 851 crossbred dairy cows, daughters of 98 sires (AI semen or bulls) were collected from the pedigree sheets at the research farm. Sires with two and more daughters were included in the data. The source of Sires (semen) were worldwide sire (WWS), Western Asia imported and domestic semen source. The traits studied were lactation milk yield (LMY), daily milk yield (DMY), lactation length (LL), age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). From the analysis, the estimated average sirebreeding value for LMY was 7.51 kg, which varied from 663.82 kg below the average to 1055.19 kg above the average. Average estimated sire-breeding value for DMY was 0.06 in the range of 1.22 kg below the average to 2.27 kg above the average breeding value. For LL, the estimated difference of sire breeding value was 97 days ranges from 49.8 days below the average to 47 days above the average. The sire breeding value of AFS trait was-0.71 days ranges from 179 days below the average to 161 days above the average. Sire-breeding value of AFC trait was-0.66 days estimated from 257 days below the average to 366 days above the average. Average sire breeding value for CI was-1.87 days ranges from 50 days below the average to 39 days above Kefale Getahun GLOBAL JOURNAL OF ANIMAL SCIENTIFIC RESEARCH, 8(3), 113-126 Page114 the average. For DO, it was-1.81 days ranged from 56 days below the average to 44 days above the average. Sire breeding value for NSC was varied from 0.02 below the average to 0.02 above the average.
Global Journal of Animal Scientific Research, Dec 3, 2020
The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lact... more The breeding values of 98 pure Holstein Friesian and crossbred sires were estimated from the lactation and reproductive performance of dairy cattle by using WOMBAT software fitted to mixed animal model evaluation method. The performance records of 851 crossbred dairy cows, daughters of 98 sires (AI semen or bulls) were collected from the pedigree sheets at the research farm. Sires with two and more daughters were included in the data. The source of Sires (semen) were worldwide sire (WWS), Western Asia imported and domestic semen source. The traits studied were lactation milk yield (LMY), daily milk yield (DMY), lactation length (LL), age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC). From the analysis, the estimated average sirebreeding value for LMY was 7.51 kg, which varied from 663.82 kg below the average to 1055.19 kg above the average. Average estimated sire-breeding value for DMY was 0.06 in the range of 1.22 kg below the average to 2.27 kg above the average breeding value. For LL, the estimated difference of sire breeding value was 97 days ranges from 49.8 days below the average to 47 days above the average. The sire breeding value of AFS trait was-0.71 days ranges from 179 days below the average to 161 days above the average. Sire-breeding value of AFC trait was-0.66 days estimated from 257 days below the average to 366 days above the average. Average sire breeding value for CI was-1.87 days ranges from 50 days below the average to 39 days above Kefale Getahun GLOBAL JOURNAL OF ANIMAL SCIENTIFIC RESEARCH, 8(3), 113-126 Page114 the average. For DO, it was-1.81 days ranged from 56 days below the average to 44 days above the average. Sire breeding value for NSC was varied from 0.02 below the average to 0.02 above the average.
Data collected from Jersey herd in the central highland environment of Ethiopia was used to estim... more Data collected from Jersey herd in the central highland environment of Ethiopia was used to estimate genetic parameter and genetic trend analysis for reproductive/fertility traits. Totally, 11,933 Jersey reproductive records recorded during the last 30 years were used for analysis. Traits studied were NSC (number of service per conception), DO (days open), CI (calving interval), AFC (age at first calving) and AFS (age at first service). Genetic and phenotypic parameters (heritability, repeatability, genetic and phenotypic correlation and estimated breeding values of individual animal) were estimated by using WOMBAT software package, version (2020) fitting a multi trait animal model. Genetic and phenotypic trends were calculated by regression of average estimated breeding values/phenotypic values of each trait on birth years. The estimated heritability for NSC, DO, CI, AFC and AFS were 0.01, 0.08, 0.04, 0.09 and 0.08, respectively while the corresponding repeatability values were 0.01, 0.11 and 0.14, respectively without the estimated values of AFC and AFS. Genetic correlations were all positive and in the range from 0.11 between DO and AFC to 0.99 between DO and CI. Phenotypic correlations were also positive and ranges from 0.16 (AFS-CI) to 0.98 (AFC-AFS). Genetic trend analysis based on birth years for NSC, DO, CI, AFC and AFS were in the favorable direction and found to be-0.002,-0.82 day,-0.6 day,-0.002 month and-0.002 month, respectively whereas phenotypic trends were-0.05, 0.93 day, 0.81 day, 3.2 months and 2.4 months, respectively which are unfavorable direction and undesirable for most traits. As monitored in the present study, the reproductive/fertility performance of Jersey cows in the central highland of Ethiopia was somewhat based on genetic effects but larger undesirable environmental components for the total phenotypic value.
Background: The productivity and profitability of dairy cattle depend largely on reproductive per... more Background: The productivity and profitability of dairy cattle depend largely on reproductive performance. Thus, this study was intended to evaluate the reproductive performance of Jersey cattle raised under semi-intensive management system.Methods: A retrospective analysis consisted of data collected for the last 33 years was conducted. The fixed effects fitted were birth period, calving period, service period, birth season, calving season, service season, parity and genetic group. The general linear model procedure of SAS was used for the statistical analysis of data.Result: The overall least-square means for age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and the number of services per conception (NSPC) were 22.93±0.22 months, 32.95±0.22 months, 494.16±3.68 days, 221.09±3.73 days and 1.99±0.03, respectively. Year, season and parity had a significant effect on most of the investigated reproductive traits. Imported Jersey cows had an ex...
Abstract Crossbreeding for improving milk yield and reproductive performances had started and imp... more Abstract Crossbreeding for improving milk yield and reproductive performances had started and implemented been long in
Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the
status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different
stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia
varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from
1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station
conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first
service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and
1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive
performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein
Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50%
F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second
generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed
in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic
factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk
yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit
their maximum potentials because animals are subjected to different environmental effects.
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Papers by Kefale Getahun
Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the
status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different
stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia
varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from
1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station
conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first
service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and
1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive
performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein
Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50%
F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second
generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed
in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic
factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk
yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit
their maximum potentials because animals are subjected to different environmental effects.
Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the
status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different
stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia
varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from
1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station
conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first
service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and
1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive
performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein
Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50%
F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second
generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed
in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of onfarm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic
factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk
yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit
their maximum potentials because animals are subjected to different environmental effects.