I. U. Packer

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay.

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

Evaluation of carcass characteristics of Bos indicus and tropically adapted Bos taurus breeds selected for postweaning weight

Data from 9 studies were compiled to evaluate the effects of 20 yr of selection for postweaning weight (PWW) on carcass characteristics and meat quality in experimental herds of control Nellore (NeC) and selected Nellore (NeS), Caracu (CaS), Guzerah (GuS), and Gir (GiS) breeds. These studies were conducted with animals from a genetic selection program at the Experimental Station of Sertãozinho, São Paulo State, Brazil. After the performance test (168 d postweaning), bulls (n = 490) from the calf crops born between 1992 and 2000 were finished and slaughtered to evaluate carcass traits and meat quality. Treatments were different across studies. A meta-analysis was conducted with a random coefficients model in which herd was considered a fixed effect and treatments within year and year were considered as random effects. Either calculated maturity degree or initial BW was used interchangeably as the covariate, and least squares means were used in the multiple-comparison analysis. The CaS and NeS had heavier (P = 0.002) carcasses than the NeC and GiS; GuS were intermediate. The CaS had the longest carcass (P < 0.001) and heaviest spare ribs (P < 0.001), striploin (P < 0.001), and beef plate (P = 0.013). Although the body, carcass, and quarter weights of NeS were similar to those of CaS, NeS had more edible meat in the leg region than did CaS bulls. Selection for PWW increased rib-eye area in Nellore bulls. Selected Caracu had the lowest (most favorable) shear force values compared with the NeS (P = 0.003), NeC (P = 0.005), GuS (P = 0.003), and GiS (P = 0.008). Selection for PWW increased body, carcass, and meat retail weights in the Nellore without altering dressing percentage and body fat percentage.

Cow/calf preweaning efficiency of Nellore and Bos taurus x Bos indicus crosses.

The objectives of this study were to determine if percentage Bos taurus (0 or 50%) of the cow had an effect on ME requirements and milk production, and to compare cow/calf efficiency among 3 mating systems. Metabolizable energy requirements were estimated during a feeding trial that encompassed a gestation and lactation feeding trial for each of 2 groups of cows. Cows were 0 or 50% Bos taurus (100 or 50% Nellore) breed type: Nellore cows (NL; n = 10) mated to Nellore bulls, NL cows (n = 9) mated to Angus bulls, Angus x Nellore (ANL; n = 10) and Simmental x Nellore (SNL; n = 10) cows mated to Canchim (5/8 Charolais 3/8 Zebu) bulls. Cows were individually fed a total mixed diet that contained 11.3% CP and 2.23 Mcal of ME/kg of DM. At 14-d intervals, cows and calves were weighed and the amount of DM was adjusted to keep shrunk BW and BCS of cows constant. Beginning at 38 d of age, corn silage was available to calves ad libitum. Milk production at 42, 98, 126, and 180 d postpartum was measured using the weigh-suckle-weigh technique. At 190 d of age, calves were slaughtered and body composition estimated using 9-10-11th-rib section to obtain energy deposition. Regression of BW change on daily ME intake (MEI) was used to estimate MEI at zero BW change. Increase in percentage Bos taurus had a significant effect on daily ME requirements (Mcal/d) during pregnancy (P < 0.01) and lactation (P < 0.01). Percentage Bos taurus had a positive linear effect on maintenance requirements of pregnant (P = 0.07) and lactating (P < 0.01) cows; during pregnancy, the ME requirements were 91 and 86% of those in lactation (131 +/- 3.5 vs. 145 +/- 3.4 Mcal x kg(-0.75) x d(-1)) for the 0 and 50% B. taurus groups, respectively. The 50% B. taurus cows, ANL and SNL, suckling crossbred calves had greater total MEI (4,319 +/- 61 Mcal; P < 0.01) than 0% B. taurus cows suckling NL (3,484 +/- 86 Mcal) or ANL calves (3,600 +/- 91 Mcal). The 0% B. taurus cows suckling ANL calves were more efficient (45.3 +/- 1.6 g/Mcal; P = 0.03) than straightbred NL (35.1 +/- 1.5 g/Mcal) and ANL or SNL pairs (41.0 +/- 1.0 g/Mcal). Under the conditions of this study, crossbreeding improved cow/ calf efficiency and showed an advantage for cows that have lower energy requirements.

Comportamento ingestivo de ovinos e digestibilidade aparente dos nutrientes de dietas contendo casca de soja

Twoxa0trials were performed to evaluate the effects of replacing coastcross hay by soybean hulls on ewe lambs ingestive behavior and diet digestibility. In the first trial, forty-eight ewe lambs (23.1xa0kg initial BW and 124xa0days old) were assigned to a randomized block design. The control diet contained 50% coarsely chopped coastcross hay and no soybean hulls. In the remaining treatments, soybean hulls replaced hay by 12.5%, 25% or 37.5% on dry matter (DM) basis. Eating and ruminating times were determined every five min during 24xa0hours. There was a decreased linear effect for ingestive (eating, ruminating and total chewing) behavior as soybean hulls were added to the diet. In the second trial, four Santa Ines ram lambs were arranged in a 4x4 latin square design and fed the same treatments as in the first trial. There was an increased linear effect of soybean hulls on DM, organic matter (OM), NDF and hemicellulose intake and digestibilities. ADF intake also increased linearly. Soybean hulls contains lower NDF physical effectiveness as compared to coastcross hay and its addition up to 37.5% of the diet DM improved OM and DM digestibilities.

Ajuste de modelos não-lineares em estudos de associação entre polimorfismos genéticos e crescimento em bovinos de corte

Weights at birth, at weaning and monthly from 8 to 19 months of age of the 11 genotype identified by combination of polymorphic RFLPs of the genes kappa-casein-HinfI (CSN3): AA and AB, growth hormone-AluI (GH): LL and LV, and b-lactoglobulin-HaeIII (LGB): AA, AB and BB (G1=AALLAA, G2=AALLAB, G3=AALLBB, G4=AALVAB, G5=AALVBB, G6=ABLLAA, G7=ABLLAB, G8=ABLLBB, G9=ABLVAA, G10=ABLVAB e G11=ABLVBB) were used. Data were obtained from three genetic groups: ½Canchim-Nelore (CN), ½Angus-Nelore (AN) and ½Simmental-Nelore (SN), born in 1998 and 1999 in Southeast Brazil. From five nonlinear models studied: Brody, Von Bertalanffy, Richards, Gompertz and Logistic, the more adequate was the last one. The parameters A (asymptotic value), k (maturing rate) and m (inflection point) estimated by Logistic model for each animal, were analyzed by ordinary least squares, by a linear model that included, besides the overall mean, the fixed effects of the genotype, year of birth, sex and feed management. For the CN genetic groups, was detected significant effect of genotype for A and k parameters estimates. The genotypes G3 showed inferior value of A and superior of k in relation to G7 and G8. Considering the AN and SN genetic groups, the effects of genotype on A, k and m parameters were not significant. Nonlinear model application in this study of association between genetic marker and weight trait in beef cattle provided a fitted analysis of the shape of the growth curve regarding the genotype for the CSN3, GH and LGB genes.

Expression of MyoD, myogenin, myostatin and Hsp70 transcripts in chicken embryos submitted to mild cold or heat

Abstract 1. The expression of the MyoD, myogenin, myostatin and Hsp70 genes was estimated in chicken embryos submitted to mild cold (36±0.5°C) or heat (44±0.5°C) for 1xa0h. 2. Marked decreases in MyoD, myogenin and myostatin transcript levels were observed in embryos exposed to high temperature, contrasting to the higher expression of the Hsp70 mRNA detected in heat-stressed embryos. 3. The exposure of chicken embryos to low temperature significantly affected only the abundance of myogenin mRNA. 4. These findings suggest that myogenic proliferation and differentiation events are compromised by variations in environmental temperature during avian embryogenesis.

Preweaning performance and body composition of calves from straightbred Nellore and Bos taurus x Nellore crosses.

The objectives were to evaluate preweaning performance, body composition, and efficiency of calves representing straightbred Nellore (NL), F(1), and 3-breed-cross systems. Energy requirements, milk production, and efficiency of 39 cow-calf pairs were recorded from straightbred NL calves from NL cows (10), crossbred (Angus-sired) calves from NL cows (ANL: 9), and crossbred calves (CC; Canchim-sired: 5/8 Charolais, 3/8 Zebu) from ANL (10) and Simmental x NL (10) cows. Cows and their respective calves were individually fed from birth to weaning (17 to 190 d postpartum). At 38 d of age, corn silage (7.8% CP, 2.19 Mcal of ME/kg of DM) was available to calves ad libitum. Milk production at 42, 98, 126, and 180 d postpartum was recorded by weighing calves before and after suckling. The ratio between GE and ME of milk was considered 1:0.93. Calves were slaughtered at weaning and the 9th-, 10th-, and 11th-rib section was removed for body composition estimation. The ANL calves were lighter (P < 0.01) at birth than the CC calves; the NL calves were intermediate. At weaning, the CC calves were heavier (P = 0.04) than the NL and ANL calves (230 +/- 5.5 vs. 172 +/- 8.1 and 209 +/- 8.6 kg, respectively). The ANL calves had greater (371 +/- 27 Mcal; P = 0.01) silage intake than the NL (270 +/- 25 Mcal) and CC (279 +/- 17 Mcal) calves. Milk energy intake was greater for the CC calves (970 +/- 38 Mcal of ME; P = 0.005) than the NL (670 +/- 57 Mcal of ME) and ANL (743 +/- 61 Mcal of ME) calves. The ANL calves compensated for the reduced milk production of the NL cows, which supplied less of their energy requirement for growth by increased silage intake. Calves from crossbred cows received a greater proportion of their total energy intake from milk. Crossbred calves had greater (P < 0.03) retained energy (retained energy = weaning body energy - birth body energy) than the NL calves (388 +/- 23 for ANL, and 438 +/- 15 for CC vs. 312 +/- 22 Mcal for NL calves). Percentages of water (P = 0.74) and chemical fat (P = 0.51) were similar among groups (63.7 +/- 0.6 and 14.3 +/- 0.7% for ANL calves, 63.1 +/- 0.4 and 14.7 +/- 0.5% for CC calves, and 63.3 +/- 0.6 and 13.7 +/- 0.7% of empty BW for water and chemical fat, respectively, for NL calves). Energetic efficiency (kcal of retained energy/Mcal of ME intake) was similar (P = 0.52) among groups (358 +/- 22 for ANL calves, 355 +/- 14 for CC calves, and 327 +/- 22 for NL calves). The greater BW gains and the differences in empty body composition at weaning were not enough to compensate for the greater ME intake of crossbreds. In this study, the crossbreeding systems evaluated increased preweaning calf performance but did not affect gross or energetic calf efficiency.

Molecular marker heterozygosities and genetic distances as correlates of production traits in F1 bovine crosses

Several studies have investigated the relationship between heterozygosity, genetic distance and production traits. The objective of the present study was to evaluate the influence of the degree of heterozygosity and genetic distance on growth, carcass and reproductive related features in F1 bovine crosses. We tested 10 polymorphic markers in 330 purebred cattle (Nelore, Canchim, Aberdeen Angus and Simental) and 256 crossbred cattle belonging to four crossbred groups. Individual heterozygosities (Hi) and multilocus genetic similarity (Dm) were estimated and used in correlation analysis against individual phenotypic measurements. Significant (p < 0.05) Hi effects occurred for birth weight, 15 to 18 month weight, hot carcass weight and longissimus rib eye area. The extent to which increased heterozygosity (DH) in F1 crosses can be predicted from the genetic distance of parental breeds was also investigated using Neis standard genetic distance (Ds) and standard heterozygosity (Hs). High correlations were found between DHi, DHs and the Ds of the parental breeds. Our results suggest that heterozygosity of the ten molecular markers used in this study may affect live weight during at least one growth phase. Parental genetic distance was a suitable predictor of the degree of progeny heterozygosity.

Metanálise bayesiana de parâmetros genéticos para características de crescimento em bovinos de corte

Bayesian meta-analysis was performed in a data set of heritability estimates for growth traits of zebu beef cattle with 869xa0direct heritabilities, 186xa0maternal heritabilities, and 123xa0direct-maternal genetic correlation. The fitting and development of a hierarchical model made possible to obtain pooled heritability estimates for birth weight, weaning weight, weight at 365xa0days of age and weight at 550xa0days of age, whose values were, respectively: 0.31, 0.24, 0.28 e 0.33 for direct effects; 0.09, 0.13, 0.12 e 0.05 for maternal effects; and -0.16, -0.16, -0.20 e -0.16 for direct-maternal genetic correlation. Meta-analysis conducted under Bayesian framework was adequate, since hierarchical model considers between-study and within-study variances, and its implementation and conduction are facilitated, mainly, due to the advance in computational area.

Efeito da raça, dieta, época e ordem de parição na concentração de imunoglobulina G no colostro de suínos

(2) Resumo†n†Este trabalho teve por objetivo estudar os efeitos da raAa, dieta, Opoca do ano e ordem de pariAao na concentraAao de imunoglobulina G (IgG) no colostro de porcas. A†concentraAao de IgG foi determinada no colostro de 60 porcas, 33 da raAa Large White e 27 da raAa Landrace, submetidas a dietas contendo 0%, 7%, 14% e 21% de levedura seca†(LS). A†levedura seca de destilaria de AElcool de cana-de-aAœcar (Saccharomyces cerevisiae) substituiu parte do milho e do farelo de soja da raAao mantendo o nIvel de 14% de proteIna bruta. Nao foi verificado efeito significativo (P>0,05) de raAa e da dieta sobre a concentraAao de IgG do colostro. Os†valores mais elevados de IgG foram observados no colostro de porcas que pariram entre maio e outubro (P<0,05). Foram obtidos efeitos quadrAEtico (P<0,10) e cœbico (P<0,01) da ordem de pariAao sobre a concentraAao de†IgG. As† fŒmeas de primeira cria apresentaram o menor valor (P<0,05) de concentraAao de IgG (49,98-7,9†mg/mL) em relaAao ‡s fŒmeas de segunda (92,70-5,9†mg/mL), terceira (70,72-5,6†mg/mL) e quarta crias (85,56-9,0†mg/mL), evidenciando que animais com maior experiŒncia imunolUgica apresentam maior concentraAao de imunoglobulina no colostro. Termos para indexaAao: imunidade passiva, porcas, anticorpos, fatores imunolUgicos. Abstract†n†The objective of the present study was to determine the effects of breed, diet, period of the year and lactation numbers on the concentration of immunoglobulin G†(IgG) in sows colostrum. IgG†concentration was determined in colostrum of 60 sows (33 Large White and 27 Landrace) submit- ted to four different diets with 0%, 7%, 14% and 21% of dried yeast. Dried yeast from alcohol of sugar cane industry (Saccharomyces cerevisiae) was used as substitute for corn and soybean mill keeping the level of crude protein at†14%. IgG†concentration in the colostrum was not affected by breed and diet. Higher concentration of IgG was found in colostrum of sows farrowing occurred between May and October (P<0.05). Quadratic (P<0.10) and cubic (P<0.01) effects of parturition order on IgG concen- tration were detected. Females from first parturition had lower concentration (P<0.05) of IgG (49.98-7.9†mg/mL) compared to females from second (92.70-5.9†mg/mL), third (70.72-5.6†mg/mL) and fourth (85.56-9.0†mg/mL) parturition, demonstrating that animals with more immunological ex- perience have higher concentrations of IgG in the colostrum.