Avaliação das Sub-Frações dos Carboidratos e das Proteinas, Usando as Metodologias do Cncps e In situ com Bovinos da Raça Nelore. 1. Silagem de Milho

To validate the use of the Cornell Net Carbohydrate and Protein System (CNCPS) under Brazilian conditions, the chemical composition, the potential and the effective degradabilities of the carbohydrate and protein subfractions, and the solid phase passage rate were determined for corn silage in diets with forage:concentrate ratios of 80:20 (DI) and 60:40 (D2) using Nellore cattle. The chromium mordant technique was used to determine the particulate passage rate of solids. For diet 2, there was a reduction in the potentially degradable dry matter (DM), and however not significant, a reduction in the degradation rates of neutral detergent Fiber (NDF, 49%) and neutral detergent insoluble nitrogen (NDIN, 32%), and an increase in the degradation rare of starch (ST, 25%). The use of lag time increased the effective DM degradation (EDDM) of corn silage in both diets (23% and 53% for D1 and D2, respectively). The concentrate ratios did not influence the particulate passage rate of the diets. The higher values related ro the availability of the protein subfractions may indicate a underestimation by CNCPS, Rnd(or) could be attributed to the Zebu animals used in this study.

GENETIC-RELATIONSHIP, INBREEDING AND GENERATION INTERVAL IN REGISTERED GIR CATTLE IN BRAZIL

Two-hundred random pedigrees of cows and fifty of sires born in 1987 from the Gir herdbook of the Brazilian Association of Zebu Breeders were analized. The bull Chave de Ouro DGR no. 2851 was the most influential animal with a 7 % direct relationship to the breed. Total average inbreeding was 3.62 and 3.25 for the female and male sample, respectively. The subdivision of total inbreeding into current and non-current components resulted in values of 1.62, 1.25, 2.00 and 2.00 for the female and male sample, respectively. Long-term inbreeding was the principal component of non-current inbreeding, with values of 1.52 % and 1.26 %, respectively. Inbreeding due to strain formation strain due formation was less important (0.48 % and 0.74 %, respectively). The average generation interval was 8.02 years. The breed appears not yet to be subdivided into strains but this process may be starting. The average generation interval for the pedigree population was very high. Culling of old bulls could decrease this interval.

Prediction of dry matter intake based on ruminal degradation from milking cows grazing coast-cross grass

Dry matter intake (DMI) of coast-cross grazing by crossbred Holstein-Zebu and Zebu lactating cows was calculated using in vitro dry matter digestibility from extrusa (four esophageal fistulated cows) and fecal output estimate with mordent chromium. Pasture was rotationally grazed with three days grazing period and 27 days testing period, adopting a stocking rate of 1.6 and 3.2 cows/ha, during the dry and rainy season respectively. Voluntary DMI was estimated from degradation characteristics using different equations. Predicted coast-cross DMI varied with models. The prediction of tropical forages dry matter intake from equations based in ruminal degradation parameters needs farther investigation before being employed in practice.

Estimativas de herdabilidade e proposição de índices de seleção em Hereford no Rio Grande do Sul

A total of 8,064 records from weaning weights and conformation scores traits of calves nearly seven month-old were studied. The study included animals from 22 herds from state of Rio Grande do Sul, borned from 1973 to 1985 which were raised on pastures. The weaning weight adjusted to 205-day weight and fat deposition and the relation size-length of body were scored subjectively in a scale from zero to ten. The dates 205-day weight, fat deposition and relation size-length of body were 137.00 +/- .20 kg; 6.38 +/- 01 and 6.77 +/- 01 grades, respectively. The heritability estimates were .25 +/- .03, .38 +/- 04 and .37 +/- 04, respectively. The selection index was more efficient than direct phenotypic selection and this study also indicates that general selection index is not adequated to use it in all farms, and it is not necessary to have accurate economic values. The most important parameters to get good selection are reliable estimates of genetic and phenotypic variances and covariances.

Estimativas de (Co)Variâncias e Tendências Genéticas para Pesos em um Rebanho Canchim

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da niacina e da monensina sódica no desempenho de novilhos em confinamento

The objective of this study was to evaluate the effects of supplementation of combined and single monensin and niacin on the productive performance of crossbred young bulls (european/zebu) aged 11 months and initial average liveweight of 248 kg. The experimental design was a factorial randomized arrangement. The treatments were: T1-check, T2-niacin, T3-monensin and T4-niacin+monensin. All the treatments were isoproteic (11 %CP) and isoenergetic (78% TDN), composed of 57.3% roughage and 42.7% concentrate (soybean meal, maize, minerals and buffer). Data was collected over a period of 85 days, with liveweight measured every 28 days. It was conclued that, for this diet, the single supplementation of niacin does not increase the performance of bulls, and therefor it is not recommended. However, the ionophore monensin, single or on in combination with niacin, improves the performance of the animals up to 56 days of feedlot.

Desempenho Produtivo de Animais de Quatro Raças Zebuínas, Abatidos em Três Estádios de Maturidade. 1. Ganho de Peso e de Carcaça e Eficiência de Ganho

This research was conducted to evaluate the productive performance (live weight gain and carcass weight gain and gain efficiency) of animals from four zebu breed slaughtered in three maturity stages. Thirty-six bulls from Gyr, Guzera, Mocho Tabapua and Nellore with twenty-four months of average age and average initial live weight of 357.6, 362.0, 368.6 and 376.4 kg, respectively, were used. The bulls, from each breed, were randomly assigned to individual pens and were full-fed a diet containing 50% concentrate (DM basis) and distributed to three category (1, 2 and 3) of slaughter weights. The bulls from category 1, 2 and 3 were slaughtered when reached the individual live weight of 405, 450 and 500 kg, respectively. At slaughter the empty body weight was determined. The Nellore breed bulls showed greater average empty body weight gain and carcass gain in relation to the other breeds, which did not differ among themselves. There were no differences among breeds regarding to feed efficiency (empty body weight gain efficiency and carcass gain efficiency per unit of metabolizable energy intake). The slaughter weight did not influence the empty body weight gain and carcass gain, but animals slaughtered at higher slaughter weights showed lower gain efficiency and spent more time in feedlot.

Estimativas de parâmetros genéticos para características de crescimento e produtividade em vacas da raça Canchim, utilizando-se inferência bayesiana

The objective of this study was to estimate genetic parameters for body weights at weaning (PD), 12 months old (P12) and adult age (PAD), culling age (TPR, days in herd), number (ND10) and kilograms (QD10) of calves weaned up to ten years of age, total number (NDT) and total kilograms (QDT) of calves weaned during herd life, and kilograms of calves weaned per year in herd (QTPR) of Canchim (5/8 Charolais + 3/8 Zebu) females from one herd. Data consisted of 3,249, 3.111, 1,138, 1,340, 1,362, 1,362, 1,340, 1,340 and 1,340 records of PD, P12, PAD, TPR, ND10, QD10, NDT, QDT and QTPR. respectively. Variance and covariance components were estimated by bivariate analyses between PD, P12 and PAD and other production traits using Bayesian inference. The models included the additive direct, permanent environmental and residual random effects and the fixed effects year and month of birth or calving, calving age and age of the animal, depending on the trait. QD10, QDT and QTPR of each female were obtained by adjusting the weaning weights of calves for year and month of birth, sex and age of cow. Average of heritability estimates were 0.38 (PD), 0.40 (P12), 0.54 (PAD), 0.22 (TPR), 0.22 (ND10), 0.24 (QD10), 0.23 (NDT), 0.23 (QDT) and 0.32 (QTPR), indicating genetic variability to obtain response by selection. Genetic correlations between TPR (-0.02, 0.26 and -0.12), ND10 (0.04, 0.10 and -0.29), QD10 (0.37, 0.39 and -0.13), NDT (-0.03, 0.14 and -0.25), QDT (0.20, 0.33 and -0.16), QTPR (0.21, 0.28 and -0.19) and body weights (PD, P12 and PAD) suggest that selection of females based on weaning and 12-month body weights will not affect productivity. However, it may be decreased by increasing female adult body weight.

Use of primers derived from a new sequence of the bovine Y chromosome for sexing Bos taurus and Bos indicus embryos

A bovine male-specific marker was identified in our laboratory through random amplified polymorphic DNA (RAPD) analysis. This fragment of 3216 bp was cloned, sequenced and mapped by fluorescent in situ hybridization (FISH) on the taurine Yq. Primers derived from this sequence were initially screened by polymerase chain reaction (PCR) for their ability to detect Y-specific segments in zebu and taurine genomic DNA. Two of these primers amplified a 655 bp Y-specific sequence present in taurine and zebu male genomic DNA. These primers were then used for detecting the 655 bp male sequence in DNA from 173 zebu and 30 taurine embryos, which had been previously sexed using primers for the sequence BC 1.2. The results revealed an accuracy of 100%. (C) 2002 Elsevier B.V. All rights reserved.

Avaliação das Sub-Frações dos Carboidratos e das Proteínas, Usando as Metodologias do Cncps e In situ com Bovinos da Raça Nelore. 2. Milho e Farelo de Algodão

The chemical composition of corn and cottonseed meal was determined in accordance with the Cornell Net Carbohydrate and Protein System (CNCPS) in diets with forage:concentrate ratios of 80:20 (D1) and 60:40(D2) using Nellore cattle. The potential and effective degradabilities of the carbohydrate and protein subfractions were also determined. For corn. diet 2 resulted in an increase for potentially degradable dry matter (DM). An increase was observed in the effective degradation of DM (EDDM) when lag time was not considered, however, the use of Eng time increased the EDDM for both diets, 23 and 18% for DI and D2. respectively. For cottonseed meal, diet 2 determined a reduction in the potentially degradable DM: therefore, the use of lag time increased the EDDM for bath diets, 14% for D1 and 15% for D2. The availability of corn starch (fraction B1) was lower than that determined by CNCPS. The higher values for the degradability of corn and cottonseed meal protein subfractions may indicate an underestimation by the model, and, or, could be attributed to the Zebu animals used in this study.

Morphological characterization of follicle deviation in Nelore (Bos indicus) heifers and cows

Follicle diameter deviation is defined as the beginning of the differential change in growth rates between the largest and next largest follicles subsequent to wave emergence and is considered a key component of follicle selection. Follicle selection has been extensively studied in European breeds of cattle (Bos taurus) but has not been critically studied in Zebu breeds (Bos indicus). The objectives of the present study were to determine and compare the morphological characteristics of deviation associated with the first post-ovulatory wave (Wave 1) of the estrous cycle in Nelore heifers (n = 8) and nonlactating cows (n = 11). Beginning on the day of ovulation (day 0), the three largest follicles (F1-F3, respectively) were individually tracked every 12 h for 6 d using transrectal ultrasonography. In individual animals, deviation was determined graphically using visual inspection of the diameter profiles of F1, F2 and sometimes F3 (observed deviation) and mathematically using segmented regression analysis of the diameter differences between F1 and F2 or sometimes F3 (calculated deviation). Mean day of emergence of Wave 1 when F1 reached >3 rum (approximately 1 d after ovulation) and growth rate of F1 during deviation (approximately 1.4 mm/d) were not significantly different between heifers and cows. The results of determining the beginning of deviation within heifers and cows using the observed and calculated methods were not significantly different. Averaged over both methods, diameter deviation occurred 2.8 d after ovulation when F1 reached 5.7 mm in heifers, and 2.4 d after ovulation when F1 reached 6.1 mm in cows. In conclusion, the emergence of Wave 1 and growth rates and diameters of the future dominant follicles at the beginning of deviation were similar in Nelore heifers and nonlactating cows, regardless of the methods used to determine deviation. Relative to Holstein cattle, emergence of Wave 1 appeared to occur about 1 d later and diameter of the future dominant follicle at the beginning of deviation was about 2 turn smaller in Nelore. (C) 2004 Elsevier B.V. All rights reserved.

Desempenho em pastagens e características de carcaça da 16a progênie dos rebanhos Nelore, Guzerá e Caracu de Sertãozinho (sp)

Forty one young bulls of herds selected for 378 day's weight (W378), born in 1996, were finished on pastures of Panicum Maximum (Jacq.), Panicum Maximum (Jaq) cv. Tanzania 1 and Brachiaria brizantha (Hoschst) Stapf cv. Marandu at the Sertaozinho Experimental Station, São Paulo State, Brazil. The samples, representing the W378 mean for each herd, were composed by 11 Nellore Selection (NeS) and by 10 of each one of the groups Nelore Control (NeC), Guzera Selection (GuS) and Caracu (Ca). The slaughter was carried out when the animals were 824 days older, with a body condition score averaging 7.6, in a 1-9 scale. The minimum and maximum adjusted means for the main traits, including all groups, were: average weight daily gain, 406 (NeC) and 501 g (NeS); slaughter weight (SW), 446.8 (NeC) and 544.3 kg (NeS); carcass weight (CW), 249.8 (NeC) and 309.7 kg (NeS); dressing percentage (DP), 54.0 (GuS) and 56.3% (NeC and NeS). In the 9(th) - 11(th) rib section: muscle, 59.6 (NeC) and 65.2% (Ca); fat, 15.6 (Ca) and 21.4% (NeC); bone, 18.9 (NeC) and 20.2% (GuS); fat thickness (FT), 2.0 (Ca) and 4.2 mm (NeC); loin eye area, 65.6 (NeC) and 71.1 cm(2) (NeS and Ca); Warner-Bratzler shear force (SF), 4.5 (Ca) and 6.6 kg (GuS) and total cooking losses (TCL), 22.5 (NeC) and 24.9% (GuS). The selection for weight promoted higher SW and CW in the NeS group, without changing the DP, the physical composition of the rib, SF and TCL in the meat. However, there was lower FT compared to NeC. The GuS animals had intermediates SW and CW, compared to NeS and Ca and lower DP. The Ca animals presented higher muscle percentage, in the rib section, and also higher meat tenderness compared to the meat of the Zebu animals.

Estimativas do Consumo e da Taxa de Passagem do Capim-Elefante (Pennisetum purpureum Schum.) sob Pastejo de Vacas em Lactação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da interação genótipo × ambiente sobre características de crescimento de bovinos de corte utilizando-se inferência bayesiana

The objective of this study was to evaluate the genotype x environment interaction for weaning and yearling weights, daily weight gain from weaning to 12 months of age and the growth performance in Canchim (5/8 Charolais + 3/8 Zebu) beef cattle estimated by a principal components analysis including those three traits. The environment was defined by season of birth (first and second semesters of the year). Genetic parameters were estimated by bayesian method with the Gibbs sampler using bivariate analyses (considering the trait in each of the two seasons as a different one) and models that included the fixed effects of year and month of birth, sex and age of cow (linear and quadratic) and the random effects of animal and residual. The results suggested that genetic evaluation and selection in Canchim beef cattle for the traits studied should consider the genotype and season of birth interaction.

On the Origin of Cattle: How Aurochs Became Cattle and Colonized the World

Since their domestication in the Neolithic, cattle have belonged to our cultural heritage. The reconstruction of their history is an active field of research 1 that contributes to our understanding of human history. Archeological data are now supplemented by analyses of modern and ancient samples of cattle with DNA markers of maternal, paternal, or autosomal inheritance. The most recent genetic data suggest that maternal lineages of taurine cattle originated in the Fertile Crescent with a possible contribution of South-European wild cattle populations, while zebu cattle originate from the Indus Valley. Subsequently, cattle accompanied human migrations, which led to the dispersal of domestic cattle of taurine, indicine, or mixed origin over Asia, Africa, Europe, and the New World. This has resulted in their adaptation to different environments and considerable variation in appearance and performance. More recently, rational management of breeding led to international movements of sires, which again changed the global patterns of genetic diversity.