The reactivity is an important behavioral trait that is directly linked to the economic character... more The reactivity is an important behavioral trait that is directly linked to the economic characteristics of beef. Less reactive animals have better performance and efficiency, thus, this study aimed to evaluate the influence of reactivity in the animals´ classification for residual feed intake (RFI). The study was conducted at Centro APTA Bovinos de Corte – Instituto de Zootecnia -Sertãozinho/SP. Sixty males belonging to the Traditional Nelore herd were classified into high (> mean + 0.5 SD, n = 21), medium (±0.5 SD from mean, n = 20) and low RFI (<mean - 0.5 SD, n = 19) . The animals had, on average, 256 kg and 264 days, respectively, for weight and age. They were housed in individual pens for 112 days, being 28 for adaptation to facilities and diet and 84 days for data collection. The diet was composed by Brachiaria hay, corn, cottonseed meal and mineral supplement and was offered to the animals twice a day, with ad libitum access to diet and water. The RFI was calculated as ...
Studies have shown associations between temperament traits and productivity on cattle industry, s... more Studies have shown associations between temperament traits and productivity on cattle industry, some results indicate that animals which adapt easily are less agitated, therefore there will be fewer losses in carcass due to the low incidence of hematomas and higher weight gain. The objective of this study was to associate the average daily gain in Caracu animals, subject to performance test (PT), with reactivity measured by flight speed test. The average daily gain was divided in three classes, considering 0.5 standard deviation below and above the average. The average gain classes 1, 2 and 3 was 1158.55 ± 89.48, 957.14 ± 54.77, 620.88 ± 127.41 g/day, respectively. The flight speed test (FS) measures how long the animal takes to cover a known distance after the release of the squeeze chute. Faster animals were considered more reactive. The study was performed at Centro APTA Bovinos de Corte from Instituto de Zootecnia-Sertãozinho, SP, in which were used 109 flight speed records, of ...
The residual feed intake (RFI) is a parameter used in the identification of animals with respect ... more The residual feed intake (RFI) is a parameter used in the identification of animals with respect to more efficient feed utilization. However, physiological basis are still unknown, however, the interrelationships between nutrition an immunity of the animal can contribute to the investigation of biological phenomena relevant to the RFI, since the defense system to oxidative effects caused by free radicals, is formed by acid polyunsaturated fatty acids, water soluble substances and enzymes, which derive mainly from the use of nutrients in the diet. The objective of this study was to evaluate the immunological parameters of Nellore heifers classified according to RFI. It were evaluated 176 heifers (born between 2008 and 2010), Traditional Nellore herd from Instituto de Zootecnia - Sertãozinho/SP, forming three groups of evaluation, submitted to test post weaning feed efficiency and classified into high (> mean + 0.5 SD, n= 55), medium (± 0.5 SD, n= 65) and low RFI (< mean – 0.5 S...
Studies have shown associations between temperament traits and productivity on cattle industry, s... more Studies have shown associations between temperament traits and productivity on cattle industry, some results indicate that animals which adapt easily are less agitated, therefore there will be fewer losses in carcass due to the low incidence of hematomas and higher weight gain. The objective of this study was to associate the average daily gain in Caracu animals, subject to performance test (PT), with reactivity measured by flight speed test. The average daily gain was divided in three classes, considering 0.5 standard deviation below and above the average. The average gain classes 1, 2 and 3 was 1158.55 ± 89.48, 957.14 ± 54.77, 620.88 ± 127.41 g/day, respectively. The flight speed test (FS) measures how long the animal takes to cover a known distance after the release of the squeeze chute. Faster animals were considered more reactive. The study was performed at Centro APTA Bovinos de Corte from Instituto de Zootecnia-Sertaozinho, SP, in which were used 109 flight speed records, of ...
The cattle production is a sector of agricultural activity that has impact on global warming due ... more The cattle production is a sector of agricultural activity that has impact on global warming due to enteric fermentation from digestive process that releases methane (CH4), with energy loss of food and consequent inefficiency of system. Residual feed intake (RFI) is a feed efficiency trait defined as the difference between actual feed intake and the one predicted on the basis of requirements for body weight production and maintenance. There are evidences that more efficient cattle (low RFI) have lower methane daily emissions than less efficient cattle (high RFI). This study aimed to evaluate the pattern of CH4 daily emission and its relationship with RFI obtained during the CH4 collection in Nelore previously evaluated for this trait. A sample of 23 from 62 young bulls, previously classified into low RFI72 and high RFI72 in the 72-days performance test (RFI72), were evaluated. After the 72-days test, the individual feed intake was recorded for a further 45 days. Another RFI was obta...
The reactivity is an important behavioral trait that is directly linked to the economic character... more The reactivity is an important behavioral trait that is directly linked to the economic characteristics of beef. Less reactive animals have better performance and efficiency, thus, this study aimed to evaluate the influence of reactivity in the animals´ classification for residual feed intake (RFI). The study was conducted at Centro APTA Bovinos de Corte – Instituto de Zootecnia -Sertaozinho/SP. Sixty males belonging to the Traditional Nelore herd were classified into high (> mean + 0.5 SD, n = 21), medium (±0.5 SD from mean, n = 20) and low RFI (<mean - 0.5 SD, n = 19) . The animals had, on average, 256 kg and 264 days, respectively, for weight and age. They were housed in individual pens for 112 days, being 28 for adaptation to facilities and diet and 84 days for data collection. The diet was composed by Brachiaria hay, corn, cottonseed meal and mineral supplement and was offered to the animals twice a day, with ad libitum access to diet and water. The RFI was calculated as ...
In order to minimize unwanted effects of high levels of grains in feedlot diet, antibiotic feed a... more In order to minimize unwanted effects of high levels of grains in feedlot diet, antibiotic feed additives are used, but its security is challenged and the discovery of alternative natural substances becomes necessary. The aim of the study was to evaluate the effect of increasing levels of the forage neutral detergent fiber (NDFf) and additives in feeding behavior and enteric methane emissions. Seventy Nellore bulls, (408 ± 14.17 kg initial LW), were distributed in a factorial arrangement 2 x 3 + 1, where two additives (500 mg kg-1 DM, of a blend of castor oil and cashew nut shell liquid, Essential Oligo Basics, Brazil, or 30 mg kg-1 DM of monensin), three levels of NDFf (6, 9 and 15% in DM), and control group, without additive. The diet was composed by Brachiaria hay, ground corn, citrus pulp, soybean meal and mineral salt. The experiment lasted 105d, the enteric methane emission was estimated by indicator gas SF6 methodology, in two collections for five straight days, the intake be...
The residual feed intake (RFI) is a parameter used in the identification of animals with respect ... more The residual feed intake (RFI) is a parameter used in the identification of animals with respect to more efficient feed utilization. However, physiological basis are still unknown, however, the interrelationships between nutrition an immunity of the animal can contribute to the investigation of biological phenomena relevant to the RFI, since the defense system to oxidative effects caused by free radicals, is formed by acid polyunsaturated fatty acids, water soluble substances and enzymes, which derive mainly from the use of nutrients in the diet. The objective of this study was to evaluate the immunological parameters of Nellore heifers classified according to RFI. It were evaluated 176 heifers (born between 2008 and 2010), Traditional Nellore herd from Instituto de Zootecnia - Sertaozinho/SP, forming three groups of evaluation, submitted to test post weaning feed efficiency and classified into high (> mean + 0.5 SD, n= 55), medium (± 0.5 SD, n= 65) and low RFI ( 0,005) between v...
RESUMO: O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos ... more RESUMO: O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos com quatro intervalos de tempo (10, 15, 20 e 30 minutos), para avaliação dos comportamentos comendo, ruminando, em ócio, em pé, apresentados por bovinos confinados individualmente. Foram utilizados 62 machos Nelore desmamados, confinados durante 112 dias. O comportamento foi registrado a cada 28 dias, durante 24h, por observações diretas com rota de amostragem scan e intervalos de registro de 5 minutos, para o cálculo das seguintes características: tempo de alimentação, tempo de ruminação, tempo em ócio, tempo em pé e frequência de alimentação. Foram comparados os intervalos de registro por meio de variâncias, correlações e médias das características. Observou-se para as características, tendência de aumento da variância residual à medida que o intervalo de tempo entre dois registros aumentou, com exceção da frequência alimentar, em que foi observada tendência de diminuição da variância residual com o aumento do intervalo de registro. As médias ajustadas para as medidas de comportamento ingestivo obtidas nos intervalos de registro de 5, 10, 15, 20 e 30 minutos não diferiram significativamente (P>0,05) entre si, com exceção de tempo de alimentação, que apresentou menor valor (P<0,05) no intervalo de registro de 30 minutos em comparação ao intervalo de 5 minutos. Observou-se que até o intervalo de registro de 15 minutos, as correlações com o intervalo de registro de 5 minutos podem ser consideradas altas. Entretanto, acima de 15 minutos de intervalo de registro, a correlação com o intervalo de registro de 5 minutos cai abruptamente, deixando claro que intervalos de registros superiores a 15 minutos são inadequados para estimar as características de comportamento ingestivo de bovinos avaliadas. Palavras-chave: bovinos de corte, frequência de alimentação, intervalo de registro, tempo de alimentação.
The objective of this study was to evaluate the relationship between ingestive behavior, temperam... more The objective of this study was to evaluate the relationship between ingestive behavior, temperament and residual feed intake (RFI) in Nellore cattle. Sixty-two bulls and 56 heifers after weaning, housed in individual pens, were evaluated in individual performance tests. Animals were classified as low RFI ( 0.135 kg day-1; greater than mean plus 0.5 standard deviation). Ingestive behavior was evaluated for 24 h by direct observation, every 24 days in bulls or every 10 days in heifers. Temperament was assessed by flight speed, reactivity in mobile confinement, composite score, and serum cortisol measurement. The most efficient animals (low RFI, 5.6 kg DM day-1) consumed 7% less feed than animals with medium efficiency (mean RFI, 6.0 kg DM day-1) and 13% less than the least efficient animals (high RFI, 6.34 kg DM day-1). More feed efficient animals spent a longer time feeding and ruminating per kg of DM consumed. Similarly, more efficient animals consumed less DM per hour and ruminate...
Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore ca... more Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore cattle (392 ± 27 days of age). Equations were generated from intake data and evaluated using root mean square prediction error (RMSPE), and validated by cross-validation. Equations that included DMI and hemicellulose intake (HEMI) [CH (MJ d) = 4.08(±1.65) + 11.6(±2.34)DMI(kg d) − 33.4(±7.21)HEMI(kg d)]; DMI and total carbohydrate intake (TCHI) [CH (MJ d) = 5.26(±1.69) − 6.3(±1.47)DMI(kg d) + 8.8(±1.81)TCI(kg d)]; metabolizable energy intake (MEI) and cellulose intake (CELI) [CH (MJ d) = 5.16(±1.72) − 0.13(±0.048)MEI(MJ d) + 7.37(±1.53)CELI(kg d)], and non-fiber carbohydrate intake (NFCI) [CH (MJ d) = 3.14(±1.48) + 3.65(±1.05)NFCI(kg d)] resulted in the lowest RMSPE (14.3, 14.1, 14.3 and 14.7%, respectively). When literature equations were evaluated using our database, the most accurate predictions were obtained with equations that included DMI and lignin intake (RMSPE = 15.27%) and MEI, acid detergent fiber intake and lignin intake (RMSPE = 15.7%). The mean error of predicting enteric CH4 emission with the equations developed in this study based on DMI and nutrient intake is 17% and the most accurate predictions are obtained with equations including DMI, carbohydrate intake and MEI.
Avaliou-se a digestibilidade e comportamento ingestivo em novilhas Nelore pertencentes a duas cla... more Avaliou-se a digestibilidade e comportamento ingestivo em novilhas Nelore pertencentes a duas classes de consumo alimentar residual (CAR) a fim de elucidar as fontes de variação envolvidas nas diferenças de eficiência alimentar observadas entre os animais. Trinta e duas novilhas classificadas em alto CAR (0,491± 0,51 kg de matéria seca/dia; n=15) e baixo CAR (-0,447 ± 0,51 kg de matéria seca/dia; n=17), com idade média de 502 ± 23,61 dias e peso vivo médio 364 ± 27,96 kg foram mantidas em confinamento por 42 dias, com dieta formulada à base de feno de Tifton 85, milho moído, farelo de algodão e uréia, com relação volumoso:concentrado de 45:55%. Foram avaliados a digestibilidade aparente dos nutrientes e o comportamento ingestivo dos animais. Animais baixo CAR apresentaram maior digestibilidade aparente de matéria seca (DMS), fibra em detergente neutro (DFDN), fibra em detergente ácido (DFDA) e celulose (DCEL) que animais alto CAR (49,14% versus 45,38%; 56,65% versus 49,88%; 49,96% versus 45,08%; 61,61% versus 56,40% para DMS, DFDN, DFDA, DCEL, respectivamente). Esses resultados indicaram que animais mais eficientes têm melhor aproveitamento dos alimentos. Não foram detectadas diferenças nas variáveis de comportamento ingestivo entre as classes de CAR. As variações entre os animais mais e menos eficientes podem ser, em parte, explicadas pela capacidade de digestibilidade dos nutrientes, a qual está relacionada ao comportamento ingestivo dos animais. Palavras-chave: bovinos de corte, eficiência alimentar, ingestão, ruminação.
Data from 156 Nellore males were used to develop equations for the prediction of retail beef yiel... more Data from 156 Nellore males were used to develop equations for the prediction of retail beef yield and carcass fat content, expressed as kilograms and as a percentage, from live animal and carcass measurements. Longissimus muscle area and backfat and rump fat thickness were measured by ultrasound up to 5 d before slaughter and fasted live weight was determined 1 d before slaughter. The same traits were obtained after slaughter. The carcass edible portion (CEP in kg and CEP% in percentage; n = 116) was calculated by the sum of the edible portions of primal cuts: hindquarter, forequarter, and spare ribs. Trimmable fat from the carcass boning process, with the standardization of about 3 mm of fat on retail beef, was considered to be representative of carcass fat content. Most of the variation in CEP was explained by fasted live weight or carcass weight (R 2 of 0.92 and 0.96); the same occurred for CEP% (R 2 of 0.15 and 0.13), and for CEP, the inclusion of LM area and fat thickness reduced the equation bias (lower value of Mallow's C p statistics). For trimmable fat, most variation could be explained by weight or rump fat thickness. In general, the equations developed from live animal measurements showed a predictive power similar to the equations using carcass measurements. In all cases, the traits expressed as kilograms were better predicted (R 2 of 0.39 to 0.96) than traits expressed as a percentage (R 2 of 0.08 to 0.42).
The objective of this study was to evaluate the correlated responses to selection for growth in f... more The objective of this study was to evaluate the correlated responses to selection for growth in feed efficiency and carcass traits of Nellore animals. A total of 121 animals of the Nellore control (NeC) and selection herds were subjected to performance testing and classified regarding residual feed intake (RFI). Sixty-seven of these animals were selected and finished until reaching 4 mm of subcutaneous fat thickness between the 12th and 13th ribs. The animals were slaughtered at a mean age of 541 days and mean live weight of 423 kg for NeS and of 363 kg for NeC, and carcass traits were measured. Animals in NeS presented higher initial and slaughter weights, dry matter intake, hot and cold carcass weight, weight of retail cuts, and carcass yield than NeC animals for the same slaughter age and feedlot time. No significant differences in RFI were observed between herds, showing that the weight gain from selection for growth did not cause changes in the energy efficiency of the animals.
The objectives of this study were to estimate genetic parameters for indicator traits of feed eff... more The objectives of this study were to estimate genetic parameters for indicator traits of feed efficiency and to recommend traits that would result in better responses to selection for increased weaning weight (weaning weight adjusted to 210 d of age [W210]), ADG, and metabolic BW (BW(0.75)) and lower DMI. Records of W210 from 8,004 Nellore animals born between 1978 and 2011 and postweaning performance test records from 678 males and females born between 2004 and 2011 were used. The following feed efficiency traits were evaluated: G:F, partial efficiency of growth (PEG), relative growth rate (RGR), Kleiber&#39;s ratio (KR), residual feed intake (RFI), residual weight gain (RWG), and residual intake and gain (RIG). Covariance and variance components were estimated by the restricted maximum likelihood method using multitrait analysis under an animal model. Estimates of genetic gain and correlated responses were obtained considering single-stage and 2-stage selection. Heritability estimates were 0.22 ± 0.03 (W210), 0.60 ± 0.08 (DMI), 0.42 ± 0.08 (ADG), 0.56 ± 0.06 (BW(0.75)), 0.19 ± 0.07 (G:F), 0.25 ± 0.09 (PEG), 0.19 ± 0.07 (RGR), 0.22 ± 0.07 (KR), 0.33 ± 0.10 (RFI), 0.13 ± 0.07 (RWG), and 0.19 ± 0.08 (RIG). The genetic correlations of DMI with W210 (0.64 ± 0.10), ADG (0.87 ± 0.06), and BW(0.75) (0.84 ± 0.05) were high. The only efficiency traits showing favorable responses to selection for lower DMI were G:F, PEG, RFI, and RIG. However, the use of G:F, PEG, or RFI as a selection criterion results in unfavorable correlated responses in some growth traits. The linear combination of RFI and RWG through RIG is the best selection criterion to obtain favorable responses in postweaning growth and feed intake of Nellore cattle in single-stage selection. Genetic gains in feed efficiency are expected even after preselection for W210 and subsequent feed efficiency testing of the preselected animals.
Empty body and carcass chemical compositions, expressed as content of water, ether extract, prote... more Empty body and carcass chemical compositions, expressed as content of water, ether extract, protein, minerals, and energy, were evaluated in Nellore bulls with different residual feed intakes (RFI). Forty-nine not castrated males, with 343 kg of average initial BW and 398 kg of average slaughter BW, were studied. Animals were divided in two subgroups: reference group (RG) and ad libitum feeding group. At the end of the adaptation period, animals of subgroup RG were slaughtered and the other animals were finished in individual pens for approximately 100 d, until they reached a subcutaneous fat thickness over the LM of 4 mm, and were slaughtered at an average age of 540 d. Body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Tissue deposition rates and chemical composition of gain were also measured based on gains estimated by comparative slaughter technique. No significant differences in slaughter BW (P = 0.8639), empty BW (P = 0.7288), HCW (P = 0.6563), or empty body and carcass rates of gain were observed between RFI groups, demonstrating that the low (-0.331 kg DM/d) and high (+0.325 kg DM/d) RFI animals presented similar body sizes and growth rates. No significant differences in empty body or carcass content of water, ether extract, protein, minerals, and energy were observed between the low and high RFI animals. And also there were no significant differences in empty BW or carcass gain, demonstrating that low and high RFI animals had a similar growth potential. More efficient animals (low RFI) consumed less feed than less efficient animals (high RFI) but presented similar body sizes, growth rates, and empty body and carcass chemical composition.
Aos meus pais Sergio e Odete, Meus exemplos de vida, perseverança, determinação e coragem, de car... more Aos meus pais Sergio e Odete, Meus exemplos de vida, perseverança, determinação e coragem, de caráter inigualável, responsável por tudo que sou, sempre me dando grandes ensinamentos. Ao meu marido Rodrigo, Por ser meu companheiro, pelo carinho e amor. Por toda sua compreensão, paciência e apoio durante todos os momentos de nossas vidas. Ao meu querido e amado filho João Pedro, Que me orgulha pela sua generosidade e sabedoria, que me proporciona muita paz, alegria e força para enfrentar as dificuldades da vida, sempre me inspirando na busca de ser cada vez melhor. DEDICO AGRADECIMENTOS Agradeço primeiramente a Deus, que sempre ilumina meu caminho e minhas escolhas. A meus pais, irmão, cunhada e sobrinhos por nunca duvidarem do meu potencial, estando sempre ao meu lado, me ajudando a superar todos os obstáculos sem nunca medir esforços para essa realização. Ao meu marido, por ser meu melhor e mais fiel amigo, sei que essa batalha não foi só minha e sem você seria impossível essa realização. Ao meu amado filho, saiba que você foi o maior incentivo para eu querer e conseguir ir cada vez mais longe. Ao meu orientador, Prof. Dr. Paulo Roberto Leme pela confiança, incentivo e pelos valiosos ensinamentos, saiba que foi uma enorme satisfação ter a oportunidade de conhecer e trabalhar com um profissional tão integro. A minha co-orientadora, Dra. Renata Helena Branco Arnandes, pelo apoio e sugestões para elaboração e execução deste projeto. À Fundação de Amparo e Pesquisa do Estado de São Paulo-FAPESP, pela concessão da bolsa e auxílio à pesquisa (Processo-2013/21695-7). Sem dúvida, isto foi determinante para a qualidade do trabalho e qualificação profissional da bolsista. A empresa Oligobasic pelo apoio financeiro ao projeto. A todos os funcionários, alunos e pesquisadores do Instituto de Zootecnia de Sertãozinho, pela amizade, confiança e apoio, em especial ao Sr. José Furtado, Flávio Franchini, Robson e Nena por terem me ajudado no dia a dia do experimento, saibam que vocês foram fundamentais.
Feed intake and average daily gain (ADG) in Nellore cattle were determined to calculate residual ... more Feed intake and average daily gain (ADG) in Nellore cattle were determined to calculate residual feed intake in two performance tests: first during the growth phase (RFI growth) and then during a measurement of the methane emission phase (RFI met). During the RFI growth test, 62 males and 56 females were classified as low-, medium-, and high-RFI. Enteric methane emission was measured in 46 animals; 23 males used for RFI met measurement plus 23 females (22 low-RFI growth and 24 high-RFI growth). Diet consisted of Brachiaria brizantha cv. Marandu hay (445 g/kg DM) and concentrate (555 g/kg DM). During the RFI growth and RFI met phases, DMI was lower in the animals with low RFI, with no difference in ADG. Residual feed intake was −0.359 and 0.367 kg DM/d for low-and high-RFI animals. Enteric methane emission (g/d, g/kg BW 0.75 and g/kg ADG) did not differ between RFI growth classes. Enteric methane emission (g/d) was higher in high RFI met and lower in low RFI met males. Spearman correlations among traits obtained during both tests, which were high between metabolic BW (r = 0.959) and between DMI (r = 0.718), and zero between ADG (r = −0.062), resulted in moderate correlation between RFI growth and RFI met (r = 0.412). However, it is not possible to confirm that high-efficiency animals release less enteric methane, since different results were obtained when enteric methane was compared between the RFI growth and RFI met classes.
The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to diff... more The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to different nutritional plans, as well as the intake and digestibility of nutrients from the diets supplied. Forty-seven animals in a confinement system (feedlot) were fed a corn silage-based diet for 35 days. Afterwards, these animals were evaluated in a grazing system during the rainy periods, in Urochloa brizantha cv Marandu paddocks, for 44 days. Chromic oxide was used as external marker to estimate the fecal production of animals. Samples of feces, ingredients, and pasture were collected and sampled for subsequent chemical analyses. The SF 6 tracer gas technique was adopted to quantify the methane gas emitted by the animals. The experimental design was completely randomized, using procedure GLM of software SAS (9.2), including the fixed effects of sex and nutritional plan and the linear effect of the co-variable weights. Means were analyzed by Tukey's test at 5 % probability. The intakes of total dry matter and organic matter were greater for the animals subjected to the feedlot diet (P<0.05). In this treatment, the animals showed greater dry matter digestibility, whereas the organic matter digestibility was lower (P<0.05). The digestibility of the dry matter was higher in confinement, whereas the digestibility of the organic matter was lower in this treatment (P<0.05). Emission of CH 4 /day (104.01 g) by the animals fed the feedlot diet (P<0.05) was greater, but the loss of consumed energy for methane production (CH 4 /CEB) and methane emission per dry matter consumed were lower in relation to the grazing treatment (3.75 vs 4.23 % and 11.67 vs 15.71 g/kg). The better quality of the diet in the feedlot promoted lower energy losses as methane.
The reactivity is an important behavioral trait that is directly linked to the economic character... more The reactivity is an important behavioral trait that is directly linked to the economic characteristics of beef. Less reactive animals have better performance and efficiency, thus, this study aimed to evaluate the influence of reactivity in the animals´ classification for residual feed intake (RFI). The study was conducted at Centro APTA Bovinos de Corte – Instituto de Zootecnia -Sertãozinho/SP. Sixty males belonging to the Traditional Nelore herd were classified into high (> mean + 0.5 SD, n = 21), medium (±0.5 SD from mean, n = 20) and low RFI (<mean - 0.5 SD, n = 19) . The animals had, on average, 256 kg and 264 days, respectively, for weight and age. They were housed in individual pens for 112 days, being 28 for adaptation to facilities and diet and 84 days for data collection. The diet was composed by Brachiaria hay, corn, cottonseed meal and mineral supplement and was offered to the animals twice a day, with ad libitum access to diet and water. The RFI was calculated as ...
Studies have shown associations between temperament traits and productivity on cattle industry, s... more Studies have shown associations between temperament traits and productivity on cattle industry, some results indicate that animals which adapt easily are less agitated, therefore there will be fewer losses in carcass due to the low incidence of hematomas and higher weight gain. The objective of this study was to associate the average daily gain in Caracu animals, subject to performance test (PT), with reactivity measured by flight speed test. The average daily gain was divided in three classes, considering 0.5 standard deviation below and above the average. The average gain classes 1, 2 and 3 was 1158.55 ± 89.48, 957.14 ± 54.77, 620.88 ± 127.41 g/day, respectively. The flight speed test (FS) measures how long the animal takes to cover a known distance after the release of the squeeze chute. Faster animals were considered more reactive. The study was performed at Centro APTA Bovinos de Corte from Instituto de Zootecnia-Sertãozinho, SP, in which were used 109 flight speed records, of ...
The residual feed intake (RFI) is a parameter used in the identification of animals with respect ... more The residual feed intake (RFI) is a parameter used in the identification of animals with respect to more efficient feed utilization. However, physiological basis are still unknown, however, the interrelationships between nutrition an immunity of the animal can contribute to the investigation of biological phenomena relevant to the RFI, since the defense system to oxidative effects caused by free radicals, is formed by acid polyunsaturated fatty acids, water soluble substances and enzymes, which derive mainly from the use of nutrients in the diet. The objective of this study was to evaluate the immunological parameters of Nellore heifers classified according to RFI. It were evaluated 176 heifers (born between 2008 and 2010), Traditional Nellore herd from Instituto de Zootecnia - Sertãozinho/SP, forming three groups of evaluation, submitted to test post weaning feed efficiency and classified into high (> mean + 0.5 SD, n= 55), medium (± 0.5 SD, n= 65) and low RFI (< mean – 0.5 S...
Studies have shown associations between temperament traits and productivity on cattle industry, s... more Studies have shown associations between temperament traits and productivity on cattle industry, some results indicate that animals which adapt easily are less agitated, therefore there will be fewer losses in carcass due to the low incidence of hematomas and higher weight gain. The objective of this study was to associate the average daily gain in Caracu animals, subject to performance test (PT), with reactivity measured by flight speed test. The average daily gain was divided in three classes, considering 0.5 standard deviation below and above the average. The average gain classes 1, 2 and 3 was 1158.55 ± 89.48, 957.14 ± 54.77, 620.88 ± 127.41 g/day, respectively. The flight speed test (FS) measures how long the animal takes to cover a known distance after the release of the squeeze chute. Faster animals were considered more reactive. The study was performed at Centro APTA Bovinos de Corte from Instituto de Zootecnia-Sertaozinho, SP, in which were used 109 flight speed records, of ...
The cattle production is a sector of agricultural activity that has impact on global warming due ... more The cattle production is a sector of agricultural activity that has impact on global warming due to enteric fermentation from digestive process that releases methane (CH4), with energy loss of food and consequent inefficiency of system. Residual feed intake (RFI) is a feed efficiency trait defined as the difference between actual feed intake and the one predicted on the basis of requirements for body weight production and maintenance. There are evidences that more efficient cattle (low RFI) have lower methane daily emissions than less efficient cattle (high RFI). This study aimed to evaluate the pattern of CH4 daily emission and its relationship with RFI obtained during the CH4 collection in Nelore previously evaluated for this trait. A sample of 23 from 62 young bulls, previously classified into low RFI72 and high RFI72 in the 72-days performance test (RFI72), were evaluated. After the 72-days test, the individual feed intake was recorded for a further 45 days. Another RFI was obta...
The reactivity is an important behavioral trait that is directly linked to the economic character... more The reactivity is an important behavioral trait that is directly linked to the economic characteristics of beef. Less reactive animals have better performance and efficiency, thus, this study aimed to evaluate the influence of reactivity in the animals´ classification for residual feed intake (RFI). The study was conducted at Centro APTA Bovinos de Corte – Instituto de Zootecnia -Sertaozinho/SP. Sixty males belonging to the Traditional Nelore herd were classified into high (> mean + 0.5 SD, n = 21), medium (±0.5 SD from mean, n = 20) and low RFI (<mean - 0.5 SD, n = 19) . The animals had, on average, 256 kg and 264 days, respectively, for weight and age. They were housed in individual pens for 112 days, being 28 for adaptation to facilities and diet and 84 days for data collection. The diet was composed by Brachiaria hay, corn, cottonseed meal and mineral supplement and was offered to the animals twice a day, with ad libitum access to diet and water. The RFI was calculated as ...
In order to minimize unwanted effects of high levels of grains in feedlot diet, antibiotic feed a... more In order to minimize unwanted effects of high levels of grains in feedlot diet, antibiotic feed additives are used, but its security is challenged and the discovery of alternative natural substances becomes necessary. The aim of the study was to evaluate the effect of increasing levels of the forage neutral detergent fiber (NDFf) and additives in feeding behavior and enteric methane emissions. Seventy Nellore bulls, (408 ± 14.17 kg initial LW), were distributed in a factorial arrangement 2 x 3 + 1, where two additives (500 mg kg-1 DM, of a blend of castor oil and cashew nut shell liquid, Essential Oligo Basics, Brazil, or 30 mg kg-1 DM of monensin), three levels of NDFf (6, 9 and 15% in DM), and control group, without additive. The diet was composed by Brachiaria hay, ground corn, citrus pulp, soybean meal and mineral salt. The experiment lasted 105d, the enteric methane emission was estimated by indicator gas SF6 methodology, in two collections for five straight days, the intake be...
The residual feed intake (RFI) is a parameter used in the identification of animals with respect ... more The residual feed intake (RFI) is a parameter used in the identification of animals with respect to more efficient feed utilization. However, physiological basis are still unknown, however, the interrelationships between nutrition an immunity of the animal can contribute to the investigation of biological phenomena relevant to the RFI, since the defense system to oxidative effects caused by free radicals, is formed by acid polyunsaturated fatty acids, water soluble substances and enzymes, which derive mainly from the use of nutrients in the diet. The objective of this study was to evaluate the immunological parameters of Nellore heifers classified according to RFI. It were evaluated 176 heifers (born between 2008 and 2010), Traditional Nellore herd from Instituto de Zootecnia - Sertaozinho/SP, forming three groups of evaluation, submitted to test post weaning feed efficiency and classified into high (> mean + 0.5 SD, n= 55), medium (± 0.5 SD, n= 65) and low RFI ( 0,005) between v...
RESUMO: O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos ... more RESUMO: O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos com quatro intervalos de tempo (10, 15, 20 e 30 minutos), para avaliação dos comportamentos comendo, ruminando, em ócio, em pé, apresentados por bovinos confinados individualmente. Foram utilizados 62 machos Nelore desmamados, confinados durante 112 dias. O comportamento foi registrado a cada 28 dias, durante 24h, por observações diretas com rota de amostragem scan e intervalos de registro de 5 minutos, para o cálculo das seguintes características: tempo de alimentação, tempo de ruminação, tempo em ócio, tempo em pé e frequência de alimentação. Foram comparados os intervalos de registro por meio de variâncias, correlações e médias das características. Observou-se para as características, tendência de aumento da variância residual à medida que o intervalo de tempo entre dois registros aumentou, com exceção da frequência alimentar, em que foi observada tendência de diminuição da variância residual com o aumento do intervalo de registro. As médias ajustadas para as medidas de comportamento ingestivo obtidas nos intervalos de registro de 5, 10, 15, 20 e 30 minutos não diferiram significativamente (P>0,05) entre si, com exceção de tempo de alimentação, que apresentou menor valor (P<0,05) no intervalo de registro de 30 minutos em comparação ao intervalo de 5 minutos. Observou-se que até o intervalo de registro de 15 minutos, as correlações com o intervalo de registro de 5 minutos podem ser consideradas altas. Entretanto, acima de 15 minutos de intervalo de registro, a correlação com o intervalo de registro de 5 minutos cai abruptamente, deixando claro que intervalos de registros superiores a 15 minutos são inadequados para estimar as características de comportamento ingestivo de bovinos avaliadas. Palavras-chave: bovinos de corte, frequência de alimentação, intervalo de registro, tempo de alimentação.
The objective of this study was to evaluate the relationship between ingestive behavior, temperam... more The objective of this study was to evaluate the relationship between ingestive behavior, temperament and residual feed intake (RFI) in Nellore cattle. Sixty-two bulls and 56 heifers after weaning, housed in individual pens, were evaluated in individual performance tests. Animals were classified as low RFI ( 0.135 kg day-1; greater than mean plus 0.5 standard deviation). Ingestive behavior was evaluated for 24 h by direct observation, every 24 days in bulls or every 10 days in heifers. Temperament was assessed by flight speed, reactivity in mobile confinement, composite score, and serum cortisol measurement. The most efficient animals (low RFI, 5.6 kg DM day-1) consumed 7% less feed than animals with medium efficiency (mean RFI, 6.0 kg DM day-1) and 13% less than the least efficient animals (high RFI, 6.34 kg DM day-1). More feed efficient animals spent a longer time feeding and ruminating per kg of DM consumed. Similarly, more efficient animals consumed less DM per hour and ruminate...
Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore ca... more Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore cattle (392 ± 27 days of age). Equations were generated from intake data and evaluated using root mean square prediction error (RMSPE), and validated by cross-validation. Equations that included DMI and hemicellulose intake (HEMI) [CH (MJ d) = 4.08(±1.65) + 11.6(±2.34)DMI(kg d) − 33.4(±7.21)HEMI(kg d)]; DMI and total carbohydrate intake (TCHI) [CH (MJ d) = 5.26(±1.69) − 6.3(±1.47)DMI(kg d) + 8.8(±1.81)TCI(kg d)]; metabolizable energy intake (MEI) and cellulose intake (CELI) [CH (MJ d) = 5.16(±1.72) − 0.13(±0.048)MEI(MJ d) + 7.37(±1.53)CELI(kg d)], and non-fiber carbohydrate intake (NFCI) [CH (MJ d) = 3.14(±1.48) + 3.65(±1.05)NFCI(kg d)] resulted in the lowest RMSPE (14.3, 14.1, 14.3 and 14.7%, respectively). When literature equations were evaluated using our database, the most accurate predictions were obtained with equations that included DMI and lignin intake (RMSPE = 15.27%) and MEI, acid detergent fiber intake and lignin intake (RMSPE = 15.7%). The mean error of predicting enteric CH4 emission with the equations developed in this study based on DMI and nutrient intake is 17% and the most accurate predictions are obtained with equations including DMI, carbohydrate intake and MEI.
Avaliou-se a digestibilidade e comportamento ingestivo em novilhas Nelore pertencentes a duas cla... more Avaliou-se a digestibilidade e comportamento ingestivo em novilhas Nelore pertencentes a duas classes de consumo alimentar residual (CAR) a fim de elucidar as fontes de variação envolvidas nas diferenças de eficiência alimentar observadas entre os animais. Trinta e duas novilhas classificadas em alto CAR (0,491± 0,51 kg de matéria seca/dia; n=15) e baixo CAR (-0,447 ± 0,51 kg de matéria seca/dia; n=17), com idade média de 502 ± 23,61 dias e peso vivo médio 364 ± 27,96 kg foram mantidas em confinamento por 42 dias, com dieta formulada à base de feno de Tifton 85, milho moído, farelo de algodão e uréia, com relação volumoso:concentrado de 45:55%. Foram avaliados a digestibilidade aparente dos nutrientes e o comportamento ingestivo dos animais. Animais baixo CAR apresentaram maior digestibilidade aparente de matéria seca (DMS), fibra em detergente neutro (DFDN), fibra em detergente ácido (DFDA) e celulose (DCEL) que animais alto CAR (49,14% versus 45,38%; 56,65% versus 49,88%; 49,96% versus 45,08%; 61,61% versus 56,40% para DMS, DFDN, DFDA, DCEL, respectivamente). Esses resultados indicaram que animais mais eficientes têm melhor aproveitamento dos alimentos. Não foram detectadas diferenças nas variáveis de comportamento ingestivo entre as classes de CAR. As variações entre os animais mais e menos eficientes podem ser, em parte, explicadas pela capacidade de digestibilidade dos nutrientes, a qual está relacionada ao comportamento ingestivo dos animais. Palavras-chave: bovinos de corte, eficiência alimentar, ingestão, ruminação.
Data from 156 Nellore males were used to develop equations for the prediction of retail beef yiel... more Data from 156 Nellore males were used to develop equations for the prediction of retail beef yield and carcass fat content, expressed as kilograms and as a percentage, from live animal and carcass measurements. Longissimus muscle area and backfat and rump fat thickness were measured by ultrasound up to 5 d before slaughter and fasted live weight was determined 1 d before slaughter. The same traits were obtained after slaughter. The carcass edible portion (CEP in kg and CEP% in percentage; n = 116) was calculated by the sum of the edible portions of primal cuts: hindquarter, forequarter, and spare ribs. Trimmable fat from the carcass boning process, with the standardization of about 3 mm of fat on retail beef, was considered to be representative of carcass fat content. Most of the variation in CEP was explained by fasted live weight or carcass weight (R 2 of 0.92 and 0.96); the same occurred for CEP% (R 2 of 0.15 and 0.13), and for CEP, the inclusion of LM area and fat thickness reduced the equation bias (lower value of Mallow's C p statistics). For trimmable fat, most variation could be explained by weight or rump fat thickness. In general, the equations developed from live animal measurements showed a predictive power similar to the equations using carcass measurements. In all cases, the traits expressed as kilograms were better predicted (R 2 of 0.39 to 0.96) than traits expressed as a percentage (R 2 of 0.08 to 0.42).
The objective of this study was to evaluate the correlated responses to selection for growth in f... more The objective of this study was to evaluate the correlated responses to selection for growth in feed efficiency and carcass traits of Nellore animals. A total of 121 animals of the Nellore control (NeC) and selection herds were subjected to performance testing and classified regarding residual feed intake (RFI). Sixty-seven of these animals were selected and finished until reaching 4 mm of subcutaneous fat thickness between the 12th and 13th ribs. The animals were slaughtered at a mean age of 541 days and mean live weight of 423 kg for NeS and of 363 kg for NeC, and carcass traits were measured. Animals in NeS presented higher initial and slaughter weights, dry matter intake, hot and cold carcass weight, weight of retail cuts, and carcass yield than NeC animals for the same slaughter age and feedlot time. No significant differences in RFI were observed between herds, showing that the weight gain from selection for growth did not cause changes in the energy efficiency of the animals.
The objectives of this study were to estimate genetic parameters for indicator traits of feed eff... more The objectives of this study were to estimate genetic parameters for indicator traits of feed efficiency and to recommend traits that would result in better responses to selection for increased weaning weight (weaning weight adjusted to 210 d of age [W210]), ADG, and metabolic BW (BW(0.75)) and lower DMI. Records of W210 from 8,004 Nellore animals born between 1978 and 2011 and postweaning performance test records from 678 males and females born between 2004 and 2011 were used. The following feed efficiency traits were evaluated: G:F, partial efficiency of growth (PEG), relative growth rate (RGR), Kleiber&#39;s ratio (KR), residual feed intake (RFI), residual weight gain (RWG), and residual intake and gain (RIG). Covariance and variance components were estimated by the restricted maximum likelihood method using multitrait analysis under an animal model. Estimates of genetic gain and correlated responses were obtained considering single-stage and 2-stage selection. Heritability estimates were 0.22 ± 0.03 (W210), 0.60 ± 0.08 (DMI), 0.42 ± 0.08 (ADG), 0.56 ± 0.06 (BW(0.75)), 0.19 ± 0.07 (G:F), 0.25 ± 0.09 (PEG), 0.19 ± 0.07 (RGR), 0.22 ± 0.07 (KR), 0.33 ± 0.10 (RFI), 0.13 ± 0.07 (RWG), and 0.19 ± 0.08 (RIG). The genetic correlations of DMI with W210 (0.64 ± 0.10), ADG (0.87 ± 0.06), and BW(0.75) (0.84 ± 0.05) were high. The only efficiency traits showing favorable responses to selection for lower DMI were G:F, PEG, RFI, and RIG. However, the use of G:F, PEG, or RFI as a selection criterion results in unfavorable correlated responses in some growth traits. The linear combination of RFI and RWG through RIG is the best selection criterion to obtain favorable responses in postweaning growth and feed intake of Nellore cattle in single-stage selection. Genetic gains in feed efficiency are expected even after preselection for W210 and subsequent feed efficiency testing of the preselected animals.
Empty body and carcass chemical compositions, expressed as content of water, ether extract, prote... more Empty body and carcass chemical compositions, expressed as content of water, ether extract, protein, minerals, and energy, were evaluated in Nellore bulls with different residual feed intakes (RFI). Forty-nine not castrated males, with 343 kg of average initial BW and 398 kg of average slaughter BW, were studied. Animals were divided in two subgroups: reference group (RG) and ad libitum feeding group. At the end of the adaptation period, animals of subgroup RG were slaughtered and the other animals were finished in individual pens for approximately 100 d, until they reached a subcutaneous fat thickness over the LM of 4 mm, and were slaughtered at an average age of 540 d. Body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Tissue deposition rates and chemical composition of gain were also measured based on gains estimated by comparative slaughter technique. No significant differences in slaughter BW (P = 0.8639), empty BW (P = 0.7288), HCW (P = 0.6563), or empty body and carcass rates of gain were observed between RFI groups, demonstrating that the low (-0.331 kg DM/d) and high (+0.325 kg DM/d) RFI animals presented similar body sizes and growth rates. No significant differences in empty body or carcass content of water, ether extract, protein, minerals, and energy were observed between the low and high RFI animals. And also there were no significant differences in empty BW or carcass gain, demonstrating that low and high RFI animals had a similar growth potential. More efficient animals (low RFI) consumed less feed than less efficient animals (high RFI) but presented similar body sizes, growth rates, and empty body and carcass chemical composition.
Aos meus pais Sergio e Odete, Meus exemplos de vida, perseverança, determinação e coragem, de car... more Aos meus pais Sergio e Odete, Meus exemplos de vida, perseverança, determinação e coragem, de caráter inigualável, responsável por tudo que sou, sempre me dando grandes ensinamentos. Ao meu marido Rodrigo, Por ser meu companheiro, pelo carinho e amor. Por toda sua compreensão, paciência e apoio durante todos os momentos de nossas vidas. Ao meu querido e amado filho João Pedro, Que me orgulha pela sua generosidade e sabedoria, que me proporciona muita paz, alegria e força para enfrentar as dificuldades da vida, sempre me inspirando na busca de ser cada vez melhor. DEDICO AGRADECIMENTOS Agradeço primeiramente a Deus, que sempre ilumina meu caminho e minhas escolhas. A meus pais, irmão, cunhada e sobrinhos por nunca duvidarem do meu potencial, estando sempre ao meu lado, me ajudando a superar todos os obstáculos sem nunca medir esforços para essa realização. Ao meu marido, por ser meu melhor e mais fiel amigo, sei que essa batalha não foi só minha e sem você seria impossível essa realização. Ao meu amado filho, saiba que você foi o maior incentivo para eu querer e conseguir ir cada vez mais longe. Ao meu orientador, Prof. Dr. Paulo Roberto Leme pela confiança, incentivo e pelos valiosos ensinamentos, saiba que foi uma enorme satisfação ter a oportunidade de conhecer e trabalhar com um profissional tão integro. A minha co-orientadora, Dra. Renata Helena Branco Arnandes, pelo apoio e sugestões para elaboração e execução deste projeto. À Fundação de Amparo e Pesquisa do Estado de São Paulo-FAPESP, pela concessão da bolsa e auxílio à pesquisa (Processo-2013/21695-7). Sem dúvida, isto foi determinante para a qualidade do trabalho e qualificação profissional da bolsista. A empresa Oligobasic pelo apoio financeiro ao projeto. A todos os funcionários, alunos e pesquisadores do Instituto de Zootecnia de Sertãozinho, pela amizade, confiança e apoio, em especial ao Sr. José Furtado, Flávio Franchini, Robson e Nena por terem me ajudado no dia a dia do experimento, saibam que vocês foram fundamentais.
Feed intake and average daily gain (ADG) in Nellore cattle were determined to calculate residual ... more Feed intake and average daily gain (ADG) in Nellore cattle were determined to calculate residual feed intake in two performance tests: first during the growth phase (RFI growth) and then during a measurement of the methane emission phase (RFI met). During the RFI growth test, 62 males and 56 females were classified as low-, medium-, and high-RFI. Enteric methane emission was measured in 46 animals; 23 males used for RFI met measurement plus 23 females (22 low-RFI growth and 24 high-RFI growth). Diet consisted of Brachiaria brizantha cv. Marandu hay (445 g/kg DM) and concentrate (555 g/kg DM). During the RFI growth and RFI met phases, DMI was lower in the animals with low RFI, with no difference in ADG. Residual feed intake was −0.359 and 0.367 kg DM/d for low-and high-RFI animals. Enteric methane emission (g/d, g/kg BW 0.75 and g/kg ADG) did not differ between RFI growth classes. Enteric methane emission (g/d) was higher in high RFI met and lower in low RFI met males. Spearman correlations among traits obtained during both tests, which were high between metabolic BW (r = 0.959) and between DMI (r = 0.718), and zero between ADG (r = −0.062), resulted in moderate correlation between RFI growth and RFI met (r = 0.412). However, it is not possible to confirm that high-efficiency animals release less enteric methane, since different results were obtained when enteric methane was compared between the RFI growth and RFI met classes.
The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to diff... more The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to different nutritional plans, as well as the intake and digestibility of nutrients from the diets supplied. Forty-seven animals in a confinement system (feedlot) were fed a corn silage-based diet for 35 days. Afterwards, these animals were evaluated in a grazing system during the rainy periods, in Urochloa brizantha cv Marandu paddocks, for 44 days. Chromic oxide was used as external marker to estimate the fecal production of animals. Samples of feces, ingredients, and pasture were collected and sampled for subsequent chemical analyses. The SF 6 tracer gas technique was adopted to quantify the methane gas emitted by the animals. The experimental design was completely randomized, using procedure GLM of software SAS (9.2), including the fixed effects of sex and nutritional plan and the linear effect of the co-variable weights. Means were analyzed by Tukey's test at 5 % probability. The intakes of total dry matter and organic matter were greater for the animals subjected to the feedlot diet (P<0.05). In this treatment, the animals showed greater dry matter digestibility, whereas the organic matter digestibility was lower (P<0.05). The digestibility of the dry matter was higher in confinement, whereas the digestibility of the organic matter was lower in this treatment (P<0.05). Emission of CH 4 /day (104.01 g) by the animals fed the feedlot diet (P<0.05) was greater, but the loss of consumed energy for methane production (CH 4 /CEB) and methane emission per dry matter consumed were lower in relation to the grazing treatment (3.75 vs 4.23 % and 11.67 vs 15.71 g/kg). The better quality of the diet in the feedlot promoted lower energy losses as methane.
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