An experiment was conducted to study effects of intermittent suckling on creep feed intake and we... more An experiment was conducted to study effects of intermittent suckling on creep feed intake and weight gain of litters. Loss of weight and backfat during lactation, as well as reproductive performance, were also measured. Batches of multiparous sows (Parity 1 to 12, 4.1 on average) were either suckled intermittently (IS, eight batches; n = 50) or continuously (control, eight batches; n = 62). Litters were weaned at 27 +/- 2 d of age, on average. Litter size (11.1 +/- 0.2 piglets, on average) was standardized within a batch within 3 d of birth. All litters had free access to creep feed and water from 1 wk of age onward. In the IS group, litters were separated from the sow for a period of 12 h/d (0930 to 2130), starting 11 d before weaning. Rectal ultrasonography was applied at d 3 after weaning to check the ovaries for follicle development or presence of corpora lutea. Creep feed intake by the litters during lactation was higher in IS litters than in control litters (686 +/- 57 vs. 314 +/- 42 g/piglet, P < 0.01). The distribution of creep feed intake shifted from a skewed one, with a majority of litters consuming less than 250 g/piglet in control litters, to a normal distribution, with an average creep feed intake of 500 to 750 g/piglet in IS litters. During the 7 d after weaning, creep feed intake in IS litters was also higher (281 +/- 15 vs. 204 +/- 9 g-piglet(-1) x d(-1), P < 0.01). The ADG of piglets during lactation was negatively affected by IS, resulting in lower weight at weaning (7,229 +/- 140 vs. 7,893 +/- 145 g/piglet, P < 0.05). During the 7 d after weaning, however, ADG was higher in IS litters (255 +/- 10 vs. 177 +/- 8 g-piglet-1 x d(-1), P < 0.01), and 7 d after weaning, the weights of the litters were similar (9,011 +/- 167 vs. 9,132 +/- 164 g/ piglet, P = 0.81). The IS litters that consumed little or no feed during lactation had an ADG after lactation that was higher than in control litters, with comparable creep feed intake during lactation: 204 vs. 136 g/d. Body weight loss by the sows during lactation was lower in IS sows (-10 +/- 2 vs. -16 +/- 1 kg, P < 0.05). A higher percentage of IS sows ovulated during lactation (22 vs. 3%, P < 0.01), and weaning-to-ovulation interval (excluding sows with lactational ovulation) was shorter in IS sows (4.7 +/- 0.2 vs. 5.3 +/- 0.2 d, P < 0.05). We conclude that IS increased creep feed intake during lactation, and that IS increased ADG after weaning, despite lower weaning weights. Ovulation during lactation was induced in 22% of the IS sows.
This research was conducted to determine factors that influence duration of estrus, AI strategy, ... more This research was conducted to determine factors that influence duration of estrus, AI strategy, and reproduction results between and within commercial swine farms that use AI. Data from 15,186 sows and gilts on 55 farms for a period of 6.1+/-4.2 mo per farm were used in this study. The average duration of estrus was 48.4+/-1.0 h, ranging from 31 to 64 h, and was consistent from month to month within a farm (repeatability of 86%). Differences in duration of estrus between farms accounted for 23% of the total variation in duration of estrus. On most farms (n = 45), gilts showed a shorter (P < .05) duration of estrus than sows (40.8+/-1.1 h vs 48.5+/-1.0 h). The duration of first estrus after weaning was longer (P < .0001) compared with that of repeat-breeder sows (50.2+/-1.0 h vs 46.8+/-1.0 h). Duration of estrus decreased (P < .05) when interval from weaning to estrus increased from 4 to 6 d (56.0 +/- 1.2 h vs 45.8 +/-1.2 h). The regression of interval from onset to estrus to first AI and interval from weaning to estrus varied between farms and ranged from -7.4 to +1.3 h/d; four farms had a positive relationship. Farrowing rate decreased (P < .05) from 89.7+/-2.7% to 78.2+/-5.74 when the interval from weaning to estrus increased from 4 to 10 d. The litter size decreased (P < .05) from 11.7 to 10.6 pigs when the interval from weaning to estrus increased from 4 to 7 d. Compared with a single AI, double AI in sows and gilts resulted in a 4.3 and 7.0% higher (P < .05) farrowing rate, respectively. When the first AI was performed after expected ovulation, reproduction results were lower than when AI was performed before or at expected ovulation in sows. Duration of estrus was not related to farrowing rate or litter size in individual pigs. Number of inseminations per estrus, time of AI, and duration of estrus were correlated, which made it difficult to assess which of these factors was primarily related to the farrowing rate or litter size. Knowledge of average duration of estrus on farms and of factors that influence the duration of estrus on commercial farms can help to improve the efficiency of the AI strategy specific for each farm.
Two experiments were performed. The first experiment was done to study the effects of dietary ene... more Two experiments were performed. The first experiment was done to study the effects of dietary energy source on plasma insulin concentration using five gilts in a Latin square design with two diets over two periods. The diets contained either 200 g/kg of cornstarch (Starch) or soybean oil (Fat) as energy sources. Results indicate that insulin response was greater in the Starch-fed than in the Fat-fed gilts. A second experiment was performed in which 18 multiparous sows were fed one of the two experimental diets from farrowing until slaughter at d 35 of subsequent pregnancy. All sows nursed nine pigs. Blood samples were taken from a permanent jugular vein catheter every 12 min during a 12-h period on d 109 ± 1 of pregnancy, on d 7 ± 1, 14 ± 1, and 21 ± 1 of lactation, and on the day of weaning (d 22 ± 1). From 48 h after weaning, blood samples were taken every 4 h until 24 h after ovulation. After that, blood samples were taken at 12-h intervals until d 10 after ovulation. Differences between diets in insulin response were not significant. In Starch-fed sows, LH pulsatility at d 7 of lactation was greater (P < .05), the preovulatory LH surge was greater (P < .05), and progesterone production was greater (P < .05) from 108 h until 256 h after the LH surge than in the Fat-fed sows. Results indicate that feeding Starch-rich diets to multiparous sows compared with Fat-rich diets, on an isocaloric basis, increases LH pulsatility during early lactation, the preovulatory LH surge, and progesterone production after the LH surge.
The objective of this study was to investigate the relationship between various behavioral signs ... more The objective of this study was to investigate the relationship between various behavioral signs of estrous and time of ovulation and, determine which behavioral estrous sign(s) best predicted time of ovulation. In total, 94 ovulations were observed in 67 Holstein-Friesian dairy cows. Different behavioral estrous signs were observed at 3-h intervals and their relation with time of ovulation (ultrasound examinations at 3-h intervals) was investigated. In all estrous periods, sniffing and chin resting was displayed, while mounting was displayed in 90% and standing heat in 58% of estrous periods. Estrus was more intense in primiparous cows compared to multiparous cows and when more animals were in estrus at the same time. Although, these factors influenced intensity of estrous behavioral signs, they did not influence time of ovulation. Ovulation occurred 30.0 AE 5.1 h after onset of estrus (ranging between 18.5 and 48.5 h) and 18.8 AE 4.4 h after end of estrus (ranging between 9.5 and 33.5 h). Although informative, these predictors are highly variable between individuals and the method used to determine the onset and end of estrus is time consuming this, therefore limits in their use as a practical predictor of ovulation. Sniffing and chin resting were displayed during the non-estrous period and are therefore, not useful predictors of ovulation time. For animals that displayed standing heat, onset of standing heat was a good predictor for ovulation time (occurring 26.4 AE 5.2 h before ovulation). However, standing heat was only displayed in a limited number of cows, especially when only one cow was in estrus at a time. Onset of mounting was the best predictor for time of ovulation (occurring 28.7 AE 5.3 h before ovulation), and it was displayed in www.journals.elsevierhealth.com/periodicals/the
This paper summarizes three recent studies by the same authors with the objective to study the ef... more This paper summarizes three recent studies by the same authors with the objective to study the effect of dietary energy source on the energy balance (EB) and risk for metabolic and reproductive disorders in dairy cows in early lactation. The first study, a literature survey, illustrated that feeding extra glucogenic nutrients relative to lipogenic nutrients, decreased milk fat and seems to decrease plasma non-esterified fatty acid (NEFA) and b-hydroxybutyrate (BHBA) concentration. However studies are scarce and mostly confound the effect of energy source with level of energy intake, compromising eventual effects on EB and fertility. Therefore, in the second study, 16 dairy cows were either fed a glucogenic or a lipogenic diet (isocaloric) and EB was determined in climatecontrolled respiration chambers from week 2 until 9 of lactation. Glucogenic diet decreased milk fat yield and milk energy and tended to decrease body fat mobilization compared with lipogenic diet. The objective of the third study was to study the effect of dietary energy source on EB, metabolites and reproduction variables. Dairy cows (n = 111) were fed glucogenic, lipogenic or mixed diet from week 3 until week 9 relative to calving. Multiparous cows fed glucogenic diet had lower milk fat yield, higher calculated EB, and lower plasma NEFA, BHBA and liver triacylglyceride concentration and tended to have fewer days to first postpartum ovulation. In conclusion, increasing the glucogenic nutrient availability improved the EB and had potential to reduce the risk for metabolic disorders and to improve reproductive performance in dairy cows.
Forty-eight cows Holstein Friesian x Dutch Friesian (HF x DF) were randomly assigned to 2 groups ... more Forty-eight cows Holstein Friesian x Dutch Friesian (HF x DF) were randomly assigned to 2 groups fed 1 of 2 diets (isocaloric and isonitrogenous but different in linoleic/linolenic acid ratio) from 4 wk before expected parturition until 7 d after calving. Effects of the diet on plasma linoleic/linolenic acid ratio, plasma PGFM levels and placental explusion rate were studied. Dietary treatment resulted in significant differences in linoleic/linolenic acid ratio in blood plasma (1.00 +/- .22 vs 4.41 +/- .53). The placental expulsion rate was not significantly different between the 2 treatment groups. Plasma PGFM levels, as analyzed for 28 cows from 30 d before parturition until 1.5 d after parturition, were similar for the diets. Cows with a longer placental expulsion rate had lower PGFM levels at parturition (for instance, placental expulsion rate shorter (n = 11) and longer (n = 17) than 6 h, 1248 vs 2965 pg/ml, residual standard deviation 1185 pg/ml, P &amp;amp;lt; 0.01). The results show that the dietary linoleic/linolenic acid ratio can influence the plasma linoleic/linolenic acid ratio without affecting the placental expulsion rate or plasma PGFM levels around parturition.
This study aims to examine influences of specific boar stimuli on uterine activity in estrous sow... more This study aims to examine influences of specific boar stimuli on uterine activity in estrous sows, by comparing uterine activity in presence of a mature teaser boar and a robot boar with variable stimuli. Nineteen multiparous, cyclic, commercial crossbred sows were used. Intra-luminal uterine pressure was measured using a non-surgical method for 45 min before applying one of four treatments in combination with a back-pressure-test (BPT): (1) robot with olfactory and auditory stimuli (R + O + A) (n = 16), (2) robot with auditory stimuli (R + A) (n = 16), (3) robot without additional stimuli (R) (n = 16), (4) a mature boar (boar) (n = 15). After treatment, measurements continued for 30 min. For each measurement, frequency, mean amplitude and mean duration of uterine contractions were determined. Spontaneous frequency of uterine contractions was 18.6 AE 0.7 h À1 on average and did not differ between treatments. Frequency of contractions increased significantly for the boar (+5.6 AE 1.3 h À1 ; P < 0.01), R + O + A (+3.9 AE 1.3; P < 0.01) and R + A (+2.6 AE 1.3; P < 0.05). The effect of boar presence on frequency of contractions was greater than the effect of R (P < 0.05). Amplitude and duration of contractions were not affected by treatment. The change in frequency was dependent on spontaneous frequency (P < 0.01). In conclusion, the higher the level of boar stimuli, the greater the increase in frequency of uterine contractions. The results indicate that the used combinations of artificial boar stimuli do not mimic a 'whole' boar. It is unclear which boar stimuli stimulate maximal uterine activity during estrus.
In this paper, the authors review the effects of boar contact and different components of boar pr... more In this paper, the authors review the effects of boar contact and different components of boar presence on onset and expression of estrus in weaned sows. Evidence is presented that boar contact may influence LH release, onset of follicle development and timing of ovulation after weaning. Once the sow is in estrus it is important that she shows estrous behavior, because her expression of estrus determines whether she will be inseminated. Boar contact or components thereof affect expression of estrus in sows. There are distinct differences between different components of boar contact in their effectiveness in the induction of estrous behavior (standing response) in sows. Habituation to boars (due to frequency of boar contact or housing of boars near sows) also affects estrus expression in sows. It is important to inseminate sows at the correct moment relative to ovulation. The use of different estrus detection protocols (e.g., by giving sows different levels of boar stimuli during estrus detection) may result in the definition of distinct periods of estrus that may help to predict the moment of ovulation. However, results to date are not very encouraging. Besides boar stimuli, the housing conditions of sows may affect onset of estrus and estrus expression. This paper focuses on social sow-to-sow interactions. The effects of group housing (as compared to individual housing) on onset of estrus and expression of estrus are equivocal. These effects likely depend on factors like aggression between pen mates, reproductive status of pen mates and social rank of sows within the group.
This paper describes changes in spontaneous myometrial activity around estrus, factors that affec... more This paper describes changes in spontaneous myometrial activity around estrus, factors that affect myometrial activity, and the possible role of uterine contractions in the process of (artificial) insemination, sperm transport and fertilization. Myometrial activity in the sow increases during estrus. The activity is myogenic in origin, but several factors have been shown to affect myometrial activity. Natural mating stimulates uterine contractions through several mechanisms. The presence of a boar, rather than the act of mating, induces central oxytocin release in the sow and thus increases uterine activity. Estrogens in the ejaculate of a boar can trigger prostaglandin release by the endometrium and thus increase uterine activity. Tactile stimulation of the genital tract (cervix) or tactile stimulation of the back and flanks of the sow during artificial insemination does not cause a release of oxytocin. There is hardly any evidence for the effects of these latter stimuli on uterine activity, and if they are present at all, the effects are very small. Evidence for the effects of synthetic boar odor on oxytocin release and/or uterine activity is inconsistent. The mere presence of a boar during insemination, in contrast, clearly stimulates uterine activity through the release of oxytocin. Hormonal stimulation (intrauterine) of uterine activity with estrogens, prostaglandins, or oxytocins before, during or after insemination generally improves fertilization rate, especially in situations with reduced fertility. Therefore, uterine contractions are believed to play an important role in the transport of sperm cells to the oviducts after insemination. Whether uterine contractions are absolutely necessary for sperm transport through the uterine horns, however, is not clear. Intensive stimulation of uterine contractions using hormones can also reduce the fertilization rate, probably by increasing the reflux of sperm cells during insemination. In this respect, the presence of a boar during www.journals.elsevierhealth.com/periodicals/the Theriogenology 63 (2005) 500-513
ContentsIn pig husbandry, stress is being considered an important cause of impaired reproductive ... more ContentsIn pig husbandry, stress is being considered an important cause of impaired reproductive performance. Therefore, an experiment was performed to quantify effects of repeated stressors during the follicular phase and/or during early pregnancy on reproductive performance of gilts. Eighty‐one cyclic gilts were assigned to one of four treatments, namely, stress treatment during the follicular phase (n = 20), stress treatment during early pregnancy (n = 20), stress treatment during both phases (n = 21) and no stress treatment (n = 20). All gilts were housed individually, but gilts in the stress treatments had no opportunity for visual or physical contact with other gilts. Further, animals in a stress‐treatment were grouped for half an hour at the start of the treatment and during the treatment period nose‐sling and an unpredictable feeding scheme were applied regularly. The extent of stress was monitored using heart rate measurements, behavioural observations and saliva cortisol l...
In laying hens, behavioral responses measured late in the laying period are associated with decre... more In laying hens, behavioral responses measured late in the laying period are associated with decreased performance. If measured early in the laying period, these behavioral responses could be used to predict performance later in life. The main objective of the present study was to investigate the association of the behavioral response toward a novel object at 23 wk of age with subsequent performance during the laying period. A total of 1,251 hens from 6 different pure-bred Rhode Island Red lines (208 hens per line on average) were housed in 318 cages (56 cages per line on average). Performance variables included egg production (both per hen-present and hen-housed); BW at 19, 51, and 69 wk of age; mortality; and feather damage at 63 wk. Hens from cages with an approach response realized greater total egg production (hen-day and hen-housed) and greater egg production in the middle (hen-housed) and end of the laying period (per hen present and hen housed) compared with hens from cages with a passive response toward the novel object. Approach responses were also associated with more feather damage, but not with BW or mortality. Low correlations were found between greater egg production and more feather damage. These results suggest that an approach response toward a novel object measured early in the laying period is associated with better performance later in the laying period. The novel object test early in the laying period can be used to predict subsequent performance, although possible causal mechanisms for this association remain to be investigated.
Chicks hatch over a time window of approximately 36 to 48 h and are removed from the hatchers onl... more Chicks hatch over a time window of approximately 36 to 48 h and are removed from the hatchers only when the majority of the chicks has hatched. Consequently, chicks are exposed to prolonged posthatch holding periods and delays in feed and water access, leading to dehydration and impaired posthatch performance. It is questionable whether the physiological requirements of the hatchlings can be met with current hatching systems. An alternative system that may better match the requirements of the hatchlings is a system that combines the hatching and brooding phase, so that feed and water can be provided immediately after hatch. Such a system, named Patio, was developed in the Netherlands and tested from 2006 to 2008, to evaluate effects on hatchability and early performance of broilers. This paper describes the Patio system and the results from these tests. A total of 21 broiler production trials (780,686 eggs) in the Patio system were evaluated at 3 locations and compared with control hatches of eggs of the same parental flock in the hatchery. Hatchability in the Patio was on average 1.45, 1.83, and 1.86% higher at location 1, 2, and 3, respectively. However, in the calculation of the hatchability in the Patio, possible second grade chicks were included, whereas these were excluded in the calculation of hatchability in the hatchery. Additionally, in the hatchery, the hatching process was interrupted earlier than in the Patio, meaning that possible late hatching chicks remained in the flock in the Patio, but not in the hatchery. In 3 trials, the Patio chicks were 11.6 to 16.3% heavier at d 0, when the hatchery chicks were placed in the broiler house. Mean cumulative 7-d mortality was only assessed in the Patio and was 1.27, 1.09, and 1.43% at location 1, 2, and 3, respectively. The Patio system appears to function as an alternative to current hatching and brooding systems. Further studies are required to determine to what extent the higher hatchability is due to second grade and to late hatching chicks.
Two experiments were carried out to study embryonic metabolic responses to short-term temperature... more Two experiments were carried out to study embryonic metabolic responses to short-term temperature fluctuations in order to explore the possibilities of using embryonic metabolic responses as a tool to control the incubation process. In the first experiment, eggshell temperature (ET) in the control group was kept constant at 37.8°C, and embryos in the experimental group were exposed to varying ET within the range of 36.8 to 38.8°C using ET steps of 0.2°C and time steps of 3 h. This was repeated in 3 periods between 6.5 and 9.5 d, 10.5 and 13.5 d, and 14.5 and 17.5 d. In the studied ET range, heat production (HP) increased linearly at 4.9% per 1°C ET. In the second experiment, a standard machine temperature (MT) was used for the control group, and eggs in the experimental group were exposed to low (MT − 0.3°C) or high (MT + 0.3°C) temperatures for 1 h of time at d 8, 9, and 11 to 16. When MT was decreased, CO 2 production initially increased at 0.5% and decreased thereafter. When
I.v.m. het spermatekort door de varkenspest werden de KI-doses sterker verdund. Op de LUW werd on... more I.v.m. het spermatekort door de varkenspest werden de KI-doses sterker verdund. Op de LUW werd onderzocht of deze verminderde concentraties hebben geleid tot een verlaging van de worpgrootte
In large organic litters, relationships between piglet birth weight, piglet uniformity and prewea... more In large organic litters, relationships between piglet birth weight, piglet uniformity and preweaning piglet mortality were studied. Furthermore, effects of parity and insulin-stimulating diets during the pre-mating period on piglet birth weight, uniformity, and mortality were investigated. Organically kept sows (n = 137 sow cycles) were fed a control diet during lactation and weaning-to-insemination interval (CON), or an insulin-stimulating diet (sucrose plus lactose, both 150 g/d) during only the weaning-to-insemination interval (WII) or during the last two weeks of a 41± 4 d lactation and the weaning-to-insemination interval (LAC+ WII). Piglets (live born and stillborn) were weighed individually within 24 h after birth. Crossfostering was allowed within treatments within the first 3 d after birth. Litter size was higher for parities 3 and 4 sows compared with older sows, whereas parity 2 sows had an intermediate litter size (the number of total born piglets was 17.0, 18.8 and 16.3 for sows of parities 2, 3 + 4 and ≥5, respectively; P b 0.01). Mean birth weight (1.26 ± 0.02 kg) was not influenced by parity, but birth weight CV and percentage of piglets b 800 g increased with increasing parity class, after corrections for number of total born piglets (for parities 2, 3 + 4 and ≥5, respectively, CV of birth weights were 21.3, 23.2 and 24.8%, P = 0.05; and % piglets b 800 g were 6.2, 8.7 and 13.6%, P = 0.02). Pre-weaning piglet mortality also increased with parity class (20.9, 24.2, and 33.3% for parities 2, 3 + 4 and ≥5, respectively; P = 0.01). Litter characteristics at birth and preweaning piglet mortality were not affected by the insulin-stimulating diets before mating. Piglet mortality from d0 to 3 was strongly related with the number of total born piglets (β = 1.47%/piglet; P b 0.001), mean birth weight of the piglets (β = −30.99%/kg; P b 0.001), CV of birth weights (β =1.08%/%; Pb 0.001) and % piglets b 800 g (β =0.58%/%; Pb 0.01). It is concluded that piglet birth weight and birth weight uniformity affect pre-weaning piglet mortality in organic sows with large litters. Piglet uniformity and piglet mortality were also affected by parity, but not by pre-mating insulin-stimulating diets.
A powtb model for pip was validated. TIle modeI_opoc! at the Muoey Univenity (New Zea-\aDd) was c... more A powtb model for pip was validated. TIle modeI_opoc! at the Muoey Univenity (New Zea-\aDd) was cb.,..., bec:a .... its usumptiODJ aod str\IttuIe bave been published completely. Besides this, its structure is representative for most other swine powth models. In an experiment, two straiDJ of pip received per strain:. protein sufficient ration at either (i) 33 MJ DE/ day on averqe or (ii) 27 MJ DE/day on Iverqe or (iii) a protein deficient (SO'll. of ARC recommendation) ration fed ad lib. RotioDJ were composed by mixinI two basal feeds, containina 2S and 7% crude protein JeSpeetively. At 28, 6S _ lOS ka live-iaht, 4 pip in every Itrainxtreatment combination were slaughtered. Observed av....., daily pin, feed converaioo ratio, chemic:al body composition at slaughter and d&position rates of protein and lipid were compared to values c:alcu1ated by the model. In senera\, the model predicted the effects of the nutritional treatments adequately. Especia\\y protein deposition rate and live ... iaht pin were predicted quite accurately. However, above 6S ks live weiaht, the model undetatimated lipid depoaition rate in the protein-sufficient fed pip by 20-30'lIl. An increase in the ratio _ n lipid and protein depoaition rate at the biaher live weiahts was found. lbe model ... oumed no effect of live weiaht on this ratio. In contrast to Ihe protein-sufficient rations, in the proteindeficient treatment, lipid deposition was oveJeStimated considerably while protein depoaition rate ... predicted adequately. Results &lao indicated that the amount of water deposited for each unit of deposited protein is biaher thao predicted by the model. Main conclusion from the validation is that \be ~ wIIicb IIOOOUDts forthe minimaJ ratio of lipid to protein is dependent on Iiveweisht. Jtey ""'* pip; powtb modd; vaIidatioa; body compoaitiOD INTR.ODUcnON Several models which predict performance of growing pigs as a function of nutritional input and animal characteristic have been described in the litera
The influence of protein restriction and subsequent realimentation on protein and lipid depositio... more The influence of protein restriction and subsequent realimentation on protein and lipid deposition was studied. Between 28 kg and 65 kg live weight (LW), entire male pigs oftwo strains (a commercial and a sire strain) were given diets either deficient or adequate in protein content. From 65 to 105 kg LW all pigs were fed a protein-adequate ration. Animals were slaughtered and dissected at start, 65 and 105 kg LW. Body composition and deposition rates of protein, lipid, lean and fatty tissue for both the restriction period (28-65 kg LW) and the realimentation period (65-105 kg LW) were calculated. Protein restriction reduced feed intake (28%), live weight gain (60%), and rate of protein (75%) and lipid deposition (15%) between 28 and 65 kg live weight. At 65 kg, restricted animals had twice as much lipid and were 60 days older than controls. During realimentation, previously restricted pigs (compared to controls) had slightly (7%) reduced feed intake and 15% increased weight gain and efficiency. Protein deposition rate beyond 65 kg LW was increased by 13% and ratio of lipid to protein deposition was decreased from 1.69 to 1.23. At 105 kg, the previously restricted pigs still were older and fatter than controls, so compensation was not complete. Strains of pigs responded similarly to both restriction and realimentation. Dissection at 105 kg LW was not sensitive enough to show the effects revealed by chemical analysis. The experiment revealed that nutritional history may influence the relation between lipid deposition rate and protein deposition rate.
In female pigs feeding level has important effects on reproductive performance. This review is fo... more In female pigs feeding level has important effects on reproductive performance. This review is focused on the follicular development after low and high feeding levels during the luteal phase in gilts. Although aspects of diet composition seem to have a role in regulating reproductive performance, the most important aspect appears to be the plane of nutrition. Similar effects are described during lactation in primiparous sows, when their metabolism is challenged to its maximum. Also in this situation feeding level clearly affects weaning to oestrus interval, follicular development, oocyte maturation, ovulation rate and subsequent embryonic survival.
An experiment was conducted to study effects of intermittent suckling on creep feed intake and we... more An experiment was conducted to study effects of intermittent suckling on creep feed intake and weight gain of litters. Loss of weight and backfat during lactation, as well as reproductive performance, were also measured. Batches of multiparous sows (Parity 1 to 12, 4.1 on average) were either suckled intermittently (IS, eight batches; n = 50) or continuously (control, eight batches; n = 62). Litters were weaned at 27 +/- 2 d of age, on average. Litter size (11.1 +/- 0.2 piglets, on average) was standardized within a batch within 3 d of birth. All litters had free access to creep feed and water from 1 wk of age onward. In the IS group, litters were separated from the sow for a period of 12 h/d (0930 to 2130), starting 11 d before weaning. Rectal ultrasonography was applied at d 3 after weaning to check the ovaries for follicle development or presence of corpora lutea. Creep feed intake by the litters during lactation was higher in IS litters than in control litters (686 +/- 57 vs. 314 +/- 42 g/piglet, P &amp;amp;lt; 0.01). The distribution of creep feed intake shifted from a skewed one, with a majority of litters consuming less than 250 g/piglet in control litters, to a normal distribution, with an average creep feed intake of 500 to 750 g/piglet in IS litters. During the 7 d after weaning, creep feed intake in IS litters was also higher (281 +/- 15 vs. 204 +/- 9 g-piglet(-1) x d(-1), P &amp;amp;lt; 0.01). The ADG of piglets during lactation was negatively affected by IS, resulting in lower weight at weaning (7,229 +/- 140 vs. 7,893 +/- 145 g/piglet, P &amp;amp;lt; 0.05). During the 7 d after weaning, however, ADG was higher in IS litters (255 +/- 10 vs. 177 +/- 8 g-piglet-1 x d(-1), P &amp;amp;lt; 0.01), and 7 d after weaning, the weights of the litters were similar (9,011 +/- 167 vs. 9,132 +/- 164 g/ piglet, P = 0.81). The IS litters that consumed little or no feed during lactation had an ADG after lactation that was higher than in control litters, with comparable creep feed intake during lactation: 204 vs. 136 g/d. Body weight loss by the sows during lactation was lower in IS sows (-10 +/- 2 vs. -16 +/- 1 kg, P &amp;amp;lt; 0.05). A higher percentage of IS sows ovulated during lactation (22 vs. 3%, P &amp;amp;lt; 0.01), and weaning-to-ovulation interval (excluding sows with lactational ovulation) was shorter in IS sows (4.7 +/- 0.2 vs. 5.3 +/- 0.2 d, P &amp;amp;lt; 0.05). We conclude that IS increased creep feed intake during lactation, and that IS increased ADG after weaning, despite lower weaning weights. Ovulation during lactation was induced in 22% of the IS sows.
This research was conducted to determine factors that influence duration of estrus, AI strategy, ... more This research was conducted to determine factors that influence duration of estrus, AI strategy, and reproduction results between and within commercial swine farms that use AI. Data from 15,186 sows and gilts on 55 farms for a period of 6.1+/-4.2 mo per farm were used in this study. The average duration of estrus was 48.4+/-1.0 h, ranging from 31 to 64 h, and was consistent from month to month within a farm (repeatability of 86%). Differences in duration of estrus between farms accounted for 23% of the total variation in duration of estrus. On most farms (n = 45), gilts showed a shorter (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .05) duration of estrus than sows (40.8+/-1.1 h vs 48.5+/-1.0 h). The duration of first estrus after weaning was longer (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .0001) compared with that of repeat-breeder sows (50.2+/-1.0 h vs 46.8+/-1.0 h). Duration of estrus decreased (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .05) when interval from weaning to estrus increased from 4 to 6 d (56.0 +/- 1.2 h vs 45.8 +/-1.2 h). The regression of interval from onset to estrus to first AI and interval from weaning to estrus varied between farms and ranged from -7.4 to +1.3 h/d; four farms had a positive relationship. Farrowing rate decreased (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .05) from 89.7+/-2.7% to 78.2+/-5.74 when the interval from weaning to estrus increased from 4 to 10 d. The litter size decreased (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .05) from 11.7 to 10.6 pigs when the interval from weaning to estrus increased from 4 to 7 d. Compared with a single AI, double AI in sows and gilts resulted in a 4.3 and 7.0% higher (P &amp;amp;amp;amp;amp;amp;amp;amp;lt; .05) farrowing rate, respectively. When the first AI was performed after expected ovulation, reproduction results were lower than when AI was performed before or at expected ovulation in sows. Duration of estrus was not related to farrowing rate or litter size in individual pigs. Number of inseminations per estrus, time of AI, and duration of estrus were correlated, which made it difficult to assess which of these factors was primarily related to the farrowing rate or litter size. Knowledge of average duration of estrus on farms and of factors that influence the duration of estrus on commercial farms can help to improve the efficiency of the AI strategy specific for each farm.
Two experiments were performed. The first experiment was done to study the effects of dietary ene... more Two experiments were performed. The first experiment was done to study the effects of dietary energy source on plasma insulin concentration using five gilts in a Latin square design with two diets over two periods. The diets contained either 200 g/kg of cornstarch (Starch) or soybean oil (Fat) as energy sources. Results indicate that insulin response was greater in the Starch-fed than in the Fat-fed gilts. A second experiment was performed in which 18 multiparous sows were fed one of the two experimental diets from farrowing until slaughter at d 35 of subsequent pregnancy. All sows nursed nine pigs. Blood samples were taken from a permanent jugular vein catheter every 12 min during a 12-h period on d 109 ± 1 of pregnancy, on d 7 ± 1, 14 ± 1, and 21 ± 1 of lactation, and on the day of weaning (d 22 ± 1). From 48 h after weaning, blood samples were taken every 4 h until 24 h after ovulation. After that, blood samples were taken at 12-h intervals until d 10 after ovulation. Differences between diets in insulin response were not significant. In Starch-fed sows, LH pulsatility at d 7 of lactation was greater (P < .05), the preovulatory LH surge was greater (P < .05), and progesterone production was greater (P < .05) from 108 h until 256 h after the LH surge than in the Fat-fed sows. Results indicate that feeding Starch-rich diets to multiparous sows compared with Fat-rich diets, on an isocaloric basis, increases LH pulsatility during early lactation, the preovulatory LH surge, and progesterone production after the LH surge.
The objective of this study was to investigate the relationship between various behavioral signs ... more The objective of this study was to investigate the relationship between various behavioral signs of estrous and time of ovulation and, determine which behavioral estrous sign(s) best predicted time of ovulation. In total, 94 ovulations were observed in 67 Holstein-Friesian dairy cows. Different behavioral estrous signs were observed at 3-h intervals and their relation with time of ovulation (ultrasound examinations at 3-h intervals) was investigated. In all estrous periods, sniffing and chin resting was displayed, while mounting was displayed in 90% and standing heat in 58% of estrous periods. Estrus was more intense in primiparous cows compared to multiparous cows and when more animals were in estrus at the same time. Although, these factors influenced intensity of estrous behavioral signs, they did not influence time of ovulation. Ovulation occurred 30.0 AE 5.1 h after onset of estrus (ranging between 18.5 and 48.5 h) and 18.8 AE 4.4 h after end of estrus (ranging between 9.5 and 33.5 h). Although informative, these predictors are highly variable between individuals and the method used to determine the onset and end of estrus is time consuming this, therefore limits in their use as a practical predictor of ovulation. Sniffing and chin resting were displayed during the non-estrous period and are therefore, not useful predictors of ovulation time. For animals that displayed standing heat, onset of standing heat was a good predictor for ovulation time (occurring 26.4 AE 5.2 h before ovulation). However, standing heat was only displayed in a limited number of cows, especially when only one cow was in estrus at a time. Onset of mounting was the best predictor for time of ovulation (occurring 28.7 AE 5.3 h before ovulation), and it was displayed in www.journals.elsevierhealth.com/periodicals/the
This paper summarizes three recent studies by the same authors with the objective to study the ef... more This paper summarizes three recent studies by the same authors with the objective to study the effect of dietary energy source on the energy balance (EB) and risk for metabolic and reproductive disorders in dairy cows in early lactation. The first study, a literature survey, illustrated that feeding extra glucogenic nutrients relative to lipogenic nutrients, decreased milk fat and seems to decrease plasma non-esterified fatty acid (NEFA) and b-hydroxybutyrate (BHBA) concentration. However studies are scarce and mostly confound the effect of energy source with level of energy intake, compromising eventual effects on EB and fertility. Therefore, in the second study, 16 dairy cows were either fed a glucogenic or a lipogenic diet (isocaloric) and EB was determined in climatecontrolled respiration chambers from week 2 until 9 of lactation. Glucogenic diet decreased milk fat yield and milk energy and tended to decrease body fat mobilization compared with lipogenic diet. The objective of the third study was to study the effect of dietary energy source on EB, metabolites and reproduction variables. Dairy cows (n = 111) were fed glucogenic, lipogenic or mixed diet from week 3 until week 9 relative to calving. Multiparous cows fed glucogenic diet had lower milk fat yield, higher calculated EB, and lower plasma NEFA, BHBA and liver triacylglyceride concentration and tended to have fewer days to first postpartum ovulation. In conclusion, increasing the glucogenic nutrient availability improved the EB and had potential to reduce the risk for metabolic disorders and to improve reproductive performance in dairy cows.
Forty-eight cows Holstein Friesian x Dutch Friesian (HF x DF) were randomly assigned to 2 groups ... more Forty-eight cows Holstein Friesian x Dutch Friesian (HF x DF) were randomly assigned to 2 groups fed 1 of 2 diets (isocaloric and isonitrogenous but different in linoleic/linolenic acid ratio) from 4 wk before expected parturition until 7 d after calving. Effects of the diet on plasma linoleic/linolenic acid ratio, plasma PGFM levels and placental explusion rate were studied. Dietary treatment resulted in significant differences in linoleic/linolenic acid ratio in blood plasma (1.00 +/- .22 vs 4.41 +/- .53). The placental expulsion rate was not significantly different between the 2 treatment groups. Plasma PGFM levels, as analyzed for 28 cows from 30 d before parturition until 1.5 d after parturition, were similar for the diets. Cows with a longer placental expulsion rate had lower PGFM levels at parturition (for instance, placental expulsion rate shorter (n = 11) and longer (n = 17) than 6 h, 1248 vs 2965 pg/ml, residual standard deviation 1185 pg/ml, P &amp;amp;lt; 0.01). The results show that the dietary linoleic/linolenic acid ratio can influence the plasma linoleic/linolenic acid ratio without affecting the placental expulsion rate or plasma PGFM levels around parturition.
This study aims to examine influences of specific boar stimuli on uterine activity in estrous sow... more This study aims to examine influences of specific boar stimuli on uterine activity in estrous sows, by comparing uterine activity in presence of a mature teaser boar and a robot boar with variable stimuli. Nineteen multiparous, cyclic, commercial crossbred sows were used. Intra-luminal uterine pressure was measured using a non-surgical method for 45 min before applying one of four treatments in combination with a back-pressure-test (BPT): (1) robot with olfactory and auditory stimuli (R + O + A) (n = 16), (2) robot with auditory stimuli (R + A) (n = 16), (3) robot without additional stimuli (R) (n = 16), (4) a mature boar (boar) (n = 15). After treatment, measurements continued for 30 min. For each measurement, frequency, mean amplitude and mean duration of uterine contractions were determined. Spontaneous frequency of uterine contractions was 18.6 AE 0.7 h À1 on average and did not differ between treatments. Frequency of contractions increased significantly for the boar (+5.6 AE 1.3 h À1 ; P < 0.01), R + O + A (+3.9 AE 1.3; P < 0.01) and R + A (+2.6 AE 1.3; P < 0.05). The effect of boar presence on frequency of contractions was greater than the effect of R (P < 0.05). Amplitude and duration of contractions were not affected by treatment. The change in frequency was dependent on spontaneous frequency (P < 0.01). In conclusion, the higher the level of boar stimuli, the greater the increase in frequency of uterine contractions. The results indicate that the used combinations of artificial boar stimuli do not mimic a 'whole' boar. It is unclear which boar stimuli stimulate maximal uterine activity during estrus.
In this paper, the authors review the effects of boar contact and different components of boar pr... more In this paper, the authors review the effects of boar contact and different components of boar presence on onset and expression of estrus in weaned sows. Evidence is presented that boar contact may influence LH release, onset of follicle development and timing of ovulation after weaning. Once the sow is in estrus it is important that she shows estrous behavior, because her expression of estrus determines whether she will be inseminated. Boar contact or components thereof affect expression of estrus in sows. There are distinct differences between different components of boar contact in their effectiveness in the induction of estrous behavior (standing response) in sows. Habituation to boars (due to frequency of boar contact or housing of boars near sows) also affects estrus expression in sows. It is important to inseminate sows at the correct moment relative to ovulation. The use of different estrus detection protocols (e.g., by giving sows different levels of boar stimuli during estrus detection) may result in the definition of distinct periods of estrus that may help to predict the moment of ovulation. However, results to date are not very encouraging. Besides boar stimuli, the housing conditions of sows may affect onset of estrus and estrus expression. This paper focuses on social sow-to-sow interactions. The effects of group housing (as compared to individual housing) on onset of estrus and expression of estrus are equivocal. These effects likely depend on factors like aggression between pen mates, reproductive status of pen mates and social rank of sows within the group.
This paper describes changes in spontaneous myometrial activity around estrus, factors that affec... more This paper describes changes in spontaneous myometrial activity around estrus, factors that affect myometrial activity, and the possible role of uterine contractions in the process of (artificial) insemination, sperm transport and fertilization. Myometrial activity in the sow increases during estrus. The activity is myogenic in origin, but several factors have been shown to affect myometrial activity. Natural mating stimulates uterine contractions through several mechanisms. The presence of a boar, rather than the act of mating, induces central oxytocin release in the sow and thus increases uterine activity. Estrogens in the ejaculate of a boar can trigger prostaglandin release by the endometrium and thus increase uterine activity. Tactile stimulation of the genital tract (cervix) or tactile stimulation of the back and flanks of the sow during artificial insemination does not cause a release of oxytocin. There is hardly any evidence for the effects of these latter stimuli on uterine activity, and if they are present at all, the effects are very small. Evidence for the effects of synthetic boar odor on oxytocin release and/or uterine activity is inconsistent. The mere presence of a boar during insemination, in contrast, clearly stimulates uterine activity through the release of oxytocin. Hormonal stimulation (intrauterine) of uterine activity with estrogens, prostaglandins, or oxytocins before, during or after insemination generally improves fertilization rate, especially in situations with reduced fertility. Therefore, uterine contractions are believed to play an important role in the transport of sperm cells to the oviducts after insemination. Whether uterine contractions are absolutely necessary for sperm transport through the uterine horns, however, is not clear. Intensive stimulation of uterine contractions using hormones can also reduce the fertilization rate, probably by increasing the reflux of sperm cells during insemination. In this respect, the presence of a boar during www.journals.elsevierhealth.com/periodicals/the Theriogenology 63 (2005) 500-513
ContentsIn pig husbandry, stress is being considered an important cause of impaired reproductive ... more ContentsIn pig husbandry, stress is being considered an important cause of impaired reproductive performance. Therefore, an experiment was performed to quantify effects of repeated stressors during the follicular phase and/or during early pregnancy on reproductive performance of gilts. Eighty‐one cyclic gilts were assigned to one of four treatments, namely, stress treatment during the follicular phase (n = 20), stress treatment during early pregnancy (n = 20), stress treatment during both phases (n = 21) and no stress treatment (n = 20). All gilts were housed individually, but gilts in the stress treatments had no opportunity for visual or physical contact with other gilts. Further, animals in a stress‐treatment were grouped for half an hour at the start of the treatment and during the treatment period nose‐sling and an unpredictable feeding scheme were applied regularly. The extent of stress was monitored using heart rate measurements, behavioural observations and saliva cortisol l...
In laying hens, behavioral responses measured late in the laying period are associated with decre... more In laying hens, behavioral responses measured late in the laying period are associated with decreased performance. If measured early in the laying period, these behavioral responses could be used to predict performance later in life. The main objective of the present study was to investigate the association of the behavioral response toward a novel object at 23 wk of age with subsequent performance during the laying period. A total of 1,251 hens from 6 different pure-bred Rhode Island Red lines (208 hens per line on average) were housed in 318 cages (56 cages per line on average). Performance variables included egg production (both per hen-present and hen-housed); BW at 19, 51, and 69 wk of age; mortality; and feather damage at 63 wk. Hens from cages with an approach response realized greater total egg production (hen-day and hen-housed) and greater egg production in the middle (hen-housed) and end of the laying period (per hen present and hen housed) compared with hens from cages with a passive response toward the novel object. Approach responses were also associated with more feather damage, but not with BW or mortality. Low correlations were found between greater egg production and more feather damage. These results suggest that an approach response toward a novel object measured early in the laying period is associated with better performance later in the laying period. The novel object test early in the laying period can be used to predict subsequent performance, although possible causal mechanisms for this association remain to be investigated.
Chicks hatch over a time window of approximately 36 to 48 h and are removed from the hatchers onl... more Chicks hatch over a time window of approximately 36 to 48 h and are removed from the hatchers only when the majority of the chicks has hatched. Consequently, chicks are exposed to prolonged posthatch holding periods and delays in feed and water access, leading to dehydration and impaired posthatch performance. It is questionable whether the physiological requirements of the hatchlings can be met with current hatching systems. An alternative system that may better match the requirements of the hatchlings is a system that combines the hatching and brooding phase, so that feed and water can be provided immediately after hatch. Such a system, named Patio, was developed in the Netherlands and tested from 2006 to 2008, to evaluate effects on hatchability and early performance of broilers. This paper describes the Patio system and the results from these tests. A total of 21 broiler production trials (780,686 eggs) in the Patio system were evaluated at 3 locations and compared with control hatches of eggs of the same parental flock in the hatchery. Hatchability in the Patio was on average 1.45, 1.83, and 1.86% higher at location 1, 2, and 3, respectively. However, in the calculation of the hatchability in the Patio, possible second grade chicks were included, whereas these were excluded in the calculation of hatchability in the hatchery. Additionally, in the hatchery, the hatching process was interrupted earlier than in the Patio, meaning that possible late hatching chicks remained in the flock in the Patio, but not in the hatchery. In 3 trials, the Patio chicks were 11.6 to 16.3% heavier at d 0, when the hatchery chicks were placed in the broiler house. Mean cumulative 7-d mortality was only assessed in the Patio and was 1.27, 1.09, and 1.43% at location 1, 2, and 3, respectively. The Patio system appears to function as an alternative to current hatching and brooding systems. Further studies are required to determine to what extent the higher hatchability is due to second grade and to late hatching chicks.
Two experiments were carried out to study embryonic metabolic responses to short-term temperature... more Two experiments were carried out to study embryonic metabolic responses to short-term temperature fluctuations in order to explore the possibilities of using embryonic metabolic responses as a tool to control the incubation process. In the first experiment, eggshell temperature (ET) in the control group was kept constant at 37.8°C, and embryos in the experimental group were exposed to varying ET within the range of 36.8 to 38.8°C using ET steps of 0.2°C and time steps of 3 h. This was repeated in 3 periods between 6.5 and 9.5 d, 10.5 and 13.5 d, and 14.5 and 17.5 d. In the studied ET range, heat production (HP) increased linearly at 4.9% per 1°C ET. In the second experiment, a standard machine temperature (MT) was used for the control group, and eggs in the experimental group were exposed to low (MT − 0.3°C) or high (MT + 0.3°C) temperatures for 1 h of time at d 8, 9, and 11 to 16. When MT was decreased, CO 2 production initially increased at 0.5% and decreased thereafter. When
I.v.m. het spermatekort door de varkenspest werden de KI-doses sterker verdund. Op de LUW werd on... more I.v.m. het spermatekort door de varkenspest werden de KI-doses sterker verdund. Op de LUW werd onderzocht of deze verminderde concentraties hebben geleid tot een verlaging van de worpgrootte
In large organic litters, relationships between piglet birth weight, piglet uniformity and prewea... more In large organic litters, relationships between piglet birth weight, piglet uniformity and preweaning piglet mortality were studied. Furthermore, effects of parity and insulin-stimulating diets during the pre-mating period on piglet birth weight, uniformity, and mortality were investigated. Organically kept sows (n = 137 sow cycles) were fed a control diet during lactation and weaning-to-insemination interval (CON), or an insulin-stimulating diet (sucrose plus lactose, both 150 g/d) during only the weaning-to-insemination interval (WII) or during the last two weeks of a 41± 4 d lactation and the weaning-to-insemination interval (LAC+ WII). Piglets (live born and stillborn) were weighed individually within 24 h after birth. Crossfostering was allowed within treatments within the first 3 d after birth. Litter size was higher for parities 3 and 4 sows compared with older sows, whereas parity 2 sows had an intermediate litter size (the number of total born piglets was 17.0, 18.8 and 16.3 for sows of parities 2, 3 + 4 and ≥5, respectively; P b 0.01). Mean birth weight (1.26 ± 0.02 kg) was not influenced by parity, but birth weight CV and percentage of piglets b 800 g increased with increasing parity class, after corrections for number of total born piglets (for parities 2, 3 + 4 and ≥5, respectively, CV of birth weights were 21.3, 23.2 and 24.8%, P = 0.05; and % piglets b 800 g were 6.2, 8.7 and 13.6%, P = 0.02). Pre-weaning piglet mortality also increased with parity class (20.9, 24.2, and 33.3% for parities 2, 3 + 4 and ≥5, respectively; P = 0.01). Litter characteristics at birth and preweaning piglet mortality were not affected by the insulin-stimulating diets before mating. Piglet mortality from d0 to 3 was strongly related with the number of total born piglets (β = 1.47%/piglet; P b 0.001), mean birth weight of the piglets (β = −30.99%/kg; P b 0.001), CV of birth weights (β =1.08%/%; Pb 0.001) and % piglets b 800 g (β =0.58%/%; Pb 0.01). It is concluded that piglet birth weight and birth weight uniformity affect pre-weaning piglet mortality in organic sows with large litters. Piglet uniformity and piglet mortality were also affected by parity, but not by pre-mating insulin-stimulating diets.
A powtb model for pip was validated. TIle modeI_opoc! at the Muoey Univenity (New Zea-\aDd) was c... more A powtb model for pip was validated. TIle modeI_opoc! at the Muoey Univenity (New Zea-\aDd) was cb.,..., bec:a .... its usumptiODJ aod str\IttuIe bave been published completely. Besides this, its structure is representative for most other swine powth models. In an experiment, two straiDJ of pip received per strain:. protein sufficient ration at either (i) 33 MJ DE/ day on averqe or (ii) 27 MJ DE/day on Iverqe or (iii) a protein deficient (SO'll. of ARC recommendation) ration fed ad lib. RotioDJ were composed by mixinI two basal feeds, containina 2S and 7% crude protein JeSpeetively. At 28, 6S _ lOS ka live-iaht, 4 pip in every Itrainxtreatment combination were slaughtered. Observed av....., daily pin, feed converaioo ratio, chemic:al body composition at slaughter and d&position rates of protein and lipid were compared to values c:alcu1ated by the model. In senera\, the model predicted the effects of the nutritional treatments adequately. Especia\\y protein deposition rate and live ... iaht pin were predicted quite accurately. However, above 6S ks live weiaht, the model undetatimated lipid depoaition rate in the protein-sufficient fed pip by 20-30'lIl. An increase in the ratio _ n lipid and protein depoaition rate at the biaher live weiahts was found. lbe model ... oumed no effect of live weiaht on this ratio. In contrast to Ihe protein-sufficient rations, in the proteindeficient treatment, lipid deposition was oveJeStimated considerably while protein depoaition rate ... predicted adequately. Results &lao indicated that the amount of water deposited for each unit of deposited protein is biaher thao predicted by the model. Main conclusion from the validation is that \be ~ wIIicb IIOOOUDts forthe minimaJ ratio of lipid to protein is dependent on Iiveweisht. Jtey ""'* pip; powtb modd; vaIidatioa; body compoaitiOD INTR.ODUcnON Several models which predict performance of growing pigs as a function of nutritional input and animal characteristic have been described in the litera
The influence of protein restriction and subsequent realimentation on protein and lipid depositio... more The influence of protein restriction and subsequent realimentation on protein and lipid deposition was studied. Between 28 kg and 65 kg live weight (LW), entire male pigs oftwo strains (a commercial and a sire strain) were given diets either deficient or adequate in protein content. From 65 to 105 kg LW all pigs were fed a protein-adequate ration. Animals were slaughtered and dissected at start, 65 and 105 kg LW. Body composition and deposition rates of protein, lipid, lean and fatty tissue for both the restriction period (28-65 kg LW) and the realimentation period (65-105 kg LW) were calculated. Protein restriction reduced feed intake (28%), live weight gain (60%), and rate of protein (75%) and lipid deposition (15%) between 28 and 65 kg live weight. At 65 kg, restricted animals had twice as much lipid and were 60 days older than controls. During realimentation, previously restricted pigs (compared to controls) had slightly (7%) reduced feed intake and 15% increased weight gain and efficiency. Protein deposition rate beyond 65 kg LW was increased by 13% and ratio of lipid to protein deposition was decreased from 1.69 to 1.23. At 105 kg, the previously restricted pigs still were older and fatter than controls, so compensation was not complete. Strains of pigs responded similarly to both restriction and realimentation. Dissection at 105 kg LW was not sensitive enough to show the effects revealed by chemical analysis. The experiment revealed that nutritional history may influence the relation between lipid deposition rate and protein deposition rate.
In female pigs feeding level has important effects on reproductive performance. This review is fo... more In female pigs feeding level has important effects on reproductive performance. This review is focused on the follicular development after low and high feeding levels during the luteal phase in gilts. Although aspects of diet composition seem to have a role in regulating reproductive performance, the most important aspect appears to be the plane of nutrition. Similar effects are described during lactation in primiparous sows, when their metabolism is challenged to its maximum. Also in this situation feeding level clearly affects weaning to oestrus interval, follicular development, oocyte maturation, ovulation rate and subsequent embryonic survival.
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Papers by B. Kemp