Ornithine alpha-ketoglutarate and creatine effects on growth and plasma metabolites of nursery pigs.
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Four experiments were conducted to determine the effect of dietary ornithine alpha-ketoglutarate (OKG) and creatine monohydrate on growth performance and plasma metabolites of nursery pigs. In each experiment, treatments were replicated with four to five pens of four to six pigs each. Each experiment lasted from 3 to 4 wk and Phase I (1.6% Lys) and Phase II (1.3 to 1.5% Lys) diets were fed for 9 to 16 d each. In Exp. 1, pigs (4.7 kg and 15 d of age) were fed diets containing 0, .10, or .75% OKG. Daily gain during a 13-d Phase I period and ADFI during Phase I and overall (29 d) were increased (P < .10) in pigs fed .75% OKG. Gain:feed ratio was not affected (P > .10) by diet. In Exp. 2, pigs (7.1 kg and 23 d of age) were fed 0 or .50% OKG during Phase I only. During Phase I, II, and overall, ADG and ADFI were not affected (P > .10) by OKG supplementation, but gain:feed was decreased during Phase I (P < .04), Phase II (P < .08), and overall (P < .04). Plasma urea N (PUN), glucose, and NEFA concentrations were not affected (P > .10) by OKG supplementation in this experiment. In Exp. 3, pigs (5.8 kg and 20 d of age) were fed diets containing 0, .10, or .50% creatine. Creatine tended to linearly decrease ADG (P = .11) and plasma albumin (P = .12) and PUN (P < .10) concentrations in Phase II (d 12 to 26). In Exp. 4, 850 mg of OKG or 750 mg of creatine was provided daily by oral capsule to pigs 4 d before weaning to 2 d after weaning. Pigs within a litter received either no capsule or capsules containing OKG or creatine. After weaning, pigs that received no capsule before weaning received no treatment, .50% creatine, or .50% OKG in the nursery diet. Pigs that received OKG before weaning received no treatment or .50% OKG, and pigs that received creatine before weaning received no treatment or .50% creatine in the nursery diet. Pigs weighed 3.9 kg 4 d before weaning and 4.9 kg at weaning at an average age of 20 d. The OKG provided by capsule decreased ADG (P < .02) and ADFI (P < .09) during Phase II. The OKG did not affect (P > .10) plasma NEFA, glucose, or urea N concentrations. Creatine added to the nursery diet increased (P < .02) ADFI and decreased (P < .10) gain:feed during Phase II and overall. Creatine in the nursery diet also increased (P < .01) PUN, but it did not affect plasma glucose or NEFA concentrations. Creatine and OKG have variable effects on growth performance and plasma metabolites of nursery pigs. (+info)
Immunoglobulin-containing cells in pig mammary gland.
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Peroxidase-labelled antisera to pig immunoglobulins A, G and M were used to study immunoglobulin-containing cell populations in pig mammary gland at different stages of gestation and lactation. Immunoglobulin-containing cells of all three classes were present several weeks before farrowing; IgA-containing cells were most numerous at all stages of lactation. (+info)
WHO accused of stifling debate about infant feeding.(75/2259)
Evidence for spontaneous postlactational estrus in gray short-tailed opossums (Monodelphis domestica).
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Previous studies of the gray short-tailed opossum have shown that ovarian activity and estrus are induced by male pheromones, but we recently documented urogenital sinus (UGS) estrus in postlactational females despite their isolation from the male stimuli known to be associated with induced estrus. Body weights and UGS smears were collected after removal of pups in midlactation (19-37 days postpartum), after weaning (55-61 days postpartum), or after pheromone exposure. Estradiol was measured by RIA in plasma samples collected from dams during lactation, after separation from pups, and at estrus. Average days to UGS estrus from pup removal or initial pheromone exposure differed (P<0.05) only between the midlactation and pheromone exposure groups. Postlactational females showed a decrease in body weight from the time of pup removal or weaning to estrus, which contrasts with the increase seen in pheromonally stimulated females. Plasma estradiol was elevated at estrus in all groups, and females that were paired with males at postlactational estrus mated and produced litters. This study demonstrates that gray short-tailed opossums consistently experience estrus within 2 wk of weaning their young and that postlactational estrus appears to be hormonally and behaviorally equivalent to estrus induced by direct exposure to male pheromones. (+info)
Effect of tropically adapted sire breeds on preweaning growth of F1 Angus calves and reproductive performance of their Angus dams.
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The objective of this study was to determine the effect of tropically adapted sire breeds on preweaning growth performance of F1 calves and on reproductive performance of their Angus dams. Angus (A) cows were bred in two consecutive years (1992 and 1993) by AI using semen from Brahman (B; Bos indicus; n = 10), Senepol (S; Bos taurus; n = 10), and Tuli (T; Sanga; n = 9) bulls. A total of 82 B x A, 85 S x A, and 91 T x A calves were born. The statistical model included the fixed effects of year, sire breed, calf sex, sire breed x calf sex, and cow parity and the random effect of sire within sire breed. Birth weight, weaning weight, 205-d adjusted weaning weight, ADG from birth to weaning, and hip height at weaning were greater (P < .001) for B x A calves than for S x A or T x A calves. Greater differences were detected between sexes for B x A than for S x A and T x A (for all traits sire breed x calf sex, P < .05). Sire breed affected (P < .01) the percentage of unassisted calvings (B x A, 87%; S x A, 98%; and T x A, 100%) and tended (P < .10) to affect the percentage of calves that survived until weaning (B x A, 90%; S x A, 94%; and T x A, 98%). Sire breed of calf did not affect (P > .10) length of gestation, and sire breed did not affect the interval from calving to first observed estrus or pregnancy in Angus dams. These results demonstrate that preweaning growth performance of B x A calves was greater than that of either S x A or T x A calves. However, use of Brahman sires on Angus dams led to calving problems and tended to reduce the percentage of calves that survived until weaning. Thus, heavier weaning weights of B x A calves would be an advantage for cow-calf producers marketing calves, but heavier birth weights and calving difficulty attributed to Brahman sires would be a disadvantage. (+info)
Preweaning growth curves in Brown Swiss and Pirenaica calves with emphasis on individual variability.
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A quadratic polynomial model with random regression coefficients was used to describe preweaning growth curves of two beef cattle breeds widely used in the Spanish Pyrenees, according to genotype and season of birth effects. In addition, parameters of individual variability that can be used in a stochastic model were obtained. Data recorded indoors from birth to weaning of 217 Brown Swiss calves (3,509 observations) born either in spring or autumn (BS-S, BS-A) and 101 spring-born Pirenaica calves (PI-S, 967 observations) were analyzed. A quadratic model accurately fitted the preweaning weights (R2 = .99). Use of random regression coefficients improved the weaning weight adjustment; the residual variance of the model with intercept and linear random coefficients (9.61 kg2) was smaller than that of the model without them (130.03 kg2). Brown Swiss-S and PI-S calves had similar birth weight (40.9 +/- .96 vs 39.4 +/- .73 kg), but BS-S calves achieved significantly higher weaning weights at 150 d of age (175.2 +/- 2.45 vs 158.4 +/- 3.17 kg). Preweaning growth patterns were different for each season of birth, but there were no differences in weaning weight at 150 d of age (172.9 +/- 2.01 BS-A vs 175.2 +/- 2.45 BS-S). Standardization of weaning weights using a linear approximation could lead to biases, especially when comparing animals from the two calving seasons. The estimate of variances of random parameters should be done within breed and season of birth in order to take into account heteroscedasticity. The variances for BS-A, BS-S, and PI-S were 39.9, 57.6, and 32.2 kg2 for the intercept, respectively, and .0159, .0141, and .0205 kg2 for the linear coefficient. Covariance between the intercept and the linear coefficient (.34 kg2) was only statistically significant in the case of BS-S. The individual variance of weight at 150 d was 424.7 kg2 and 526.7 kg2 for BS-S and PI-S, respectively, almost 65% of the observed variance of weaning weight. (+info)
Age of calf at weaning of spring-calving beef cows and the effect on cow and calf performance and production economics.
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Over a 5-yr period, spring-calving cows were used in a carry-over design experiment to evaluate effects of calf age at weaning on cow and calf performance and production economics. Weaning management groups were early (n = 60, calf age 150 d, EW), traditional (n = 60, calf age 210 d, NW), and late (n = 60, calf age 270 d, LW). Cow body condition score (BCS) and weights at the last weaning date were different (P < .05) for EW (5.8, 583 kg), NW (5.5, 560 kg), and LW (5.2, 541 kg) management groups. Pregnancy rates among groups were similar. Days on feed for groups differed (P = .001) and was 247 for EW, 204 for NW, and 164 d for LW steers. Average daily gain in the feedlot differed (P = .01) among groups and averaged 1.5 kg for LW, 1.4 kg for NW, and 1.3 kg for EW steers. Dry matter intake while steers were in the feedlot was greater (P = .001) for LW than for NW and EW calves. Hot carcass weight was greater (P = .01) for EW (328 kg) and NW (332 kg) calves than for LW (321 kg) steers, and fat depth was greater (P = .05) for EW and NW steers than for LW steers. When carcass data for the NW and LW steers were adjusted to the fat depth of EW steers, carcass characteristics among groups were similar. Net income per steer at slaughter for the feedlot phase was greater (P < .001) for the EW ($75.36) and NW ($62.16) steers than for the LW ($10.09) steers. Again, when carcass data for the NW and LW steers were adjusted to the same fat depth of the EW steers, net income differences among groups were reduced. Replacement heifers were developed in a drylot and costs were higher (P < .001) for the EW than for NW and LW heifers. Annual cow costs were greater (P < .10) for the LW ($443.45) than for the EW ($410.09) and NW ($421.35) groups. Break-even for each system on a steer financial basis was not different between the NW and LW groups, and both the NW and LW groups had lower (P = .08) break-evens than the EW group. Age of the calf at weaning affects cow weight and BCS. Net income in each system is influenced by cow costs, month of the year that steer calves are purchased into the feedlot and finished steers are sold, month of the year cull cows are marketed, and replacement heifer development costs. (+info)
Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: I. Effects of ram breed on productivity of ewes of two crossbred populations.
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Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with ewes from two breed types to produce lambs over a 3-yr period. Ewes were assigned to one of three distinct 35-d mating seasons initiated each year in August, October, and December. A different sample of six rams per breed was used each year across all three seasons, and each ram was penned with ewes of both breeds. Traits evaluated and number of ewe records were conception rate and litter weaning weight per ewe exposed (n = 3,261) and number born, litter birth weight, average birth weight, number weaned, and litter weaning weight per ewe lambing (n = 2,751). Ram breed and ewe breed interacted (P < .01) for conception rate and litter weaning weight per ewe exposed, implicating mating preferences, particularly of Romanov rams. In mixed groups of ewes exposed to Romanov rams, conception rate was 12.7% lower and litter weight weaned was 8.4 kg lower in the ewe breed presumably less preferred for mating by the rams. On a per ewe exposed basis, Romanov-sired litters produced either the largest or the smallest values for litter weaning weight, depending on the breed of ewe. Effects of ram breed on number born and litter birth weight interacted (P < .05) with season of mating. The largest litters within each ram breed were associated with the October mating season. Montadale and Romanov rams sired larger and heavier litters from August matings than from December matings, whereas the opposite was true for Dorset-sired litters. Texel- and Finnsheep-sired litters were similar in size and weight from August and December matings. Breed of ram differences affected per ewe lambing productivity measurements (P < .01). Differences between ram breeds for ewe productivity were noted, with increased number born and improved survival of crossbred progeny to weaning for Romanov-sired litters. These results may have implications for using these ram breeds as sires in different crossbreeding systems. Structured mating systems or the creation of new composite populations involving these breeds could be used to match the resources, environment, and market of specific production situations. (+info)