Eliane Sayuri Miyagi

Características de carcaças de bovinos Nelore inteiros vs castrados em duas idades, terminados em confinamento

Carcass dressing and primary cuts of Nellore cattle, submitted to the treatments: C13 = steers castrated at 13 months of age (n=26); C18 = steers castrated at 18 months of age before feedlot (n=26) and INT = intact males (n=25) was evaluated in this researach. The animals were confined per 100 days, fed diet with 12,0 % crude protein, 2.9 Mcal of DE/kg DM and forage to concentrate ratio of 60:40 (% DM), and slaughtered at 22 months of age. A completely randomized experimental design was used. The INT animals showed higher slaughter weight 395.0 kg, hot (214.89 kg) and cold - CCW (212.21 kg) carcass weights then castrated, without differences between castrated at different ages. The INT animals showed higher cold dressing percentage (53.71%) and Longissimus dorsi muscle area (LDA) (61.23 cm2) in relation to C13 (51.99% and 56.59 cm2, respectively), without differences between C13 vs C18 and C18 vs INT. The sexual condition did not influence hot dressing percentage, chilling loss, LDA/100 kg CCW, carcass length, arm length and perimeter, and side cut. The INT animals showed lower values for fat thickness in relation to castrated, that did not differ between them. The INT animals showed higher percentage for forequarter (40.13) and lower for side cut (10.22) and saw cut (50.24) than C13 (38.33; 11.09 and 51.77, respectively) and C18 (38.82; 10.73 and 51.46, respectively), without difference between them. In absolute values, INT animals showed higher forequarter weight than castrated, which did not differ between them, and higher saw cut weight than C13.

Genetic Analysis of Growth Traits in Polled Nellore Cattle Raised on Pasture in Tropical Region Using Bayesian Approaches

Components of (co)variance and genetic parameters were estimated for adjusted weights at ages 120 (W120), 240 (W240), 365 (W365) and 450 (W450) days of Polled Nellore cattle raised on pasture and born between 1987 and 2010. Analyses were performed using an animal model, considering fixed effects: herd-year-season of birth and calf sex as contemporary groups and the age of cow as a covariate. Gibbs Samplers were used to estimate (co)variance components, genetic parameters and additive genetic effects, which accounted for great proportion of total variation in these traits. High direct heritability estimates for the growth traits were revealed and presented mean 0.43, 0.61, 0.72 and 0.67 for W120, W240, W365 and W450, respectively. Maternal heritabilities were 0.07 and 0.08 for W120 and W240, respectively. Direct additive genetic correlations between the weight at 120, 240, 365 and 450 days old were strong and positive. These estimates ranged from 0.68 to 0.98. Direct-maternal genetic correlations were negative for W120 and W240. The estimates ranged from −0.31 to −0.54. Estimates of maternal heritability ranged from 0.056 to 0.092 for W120 and from 0.064 to 0.096 for W240. This study showed that genetic progress is possible for the growth traits we studied, which is a novel and favorable indicator for an upcoming and promising Polled Zebu breed in Tropical regions. Maternal effects influenced the performance of weight at 120 and 240 days old. These effects should be taken into account in genetic analyses of growth traits by fitting them as a genetic or a permanent environmental effect, or even both. In general, due to a medium-high estimate of environmental (co)variance components, management and feeding conditions for Polled Nellore raised at pasture in tropical regions of Brazil needs improvement and growth performance can be enhanced.

Genótipo e condição sexual no desempenho e nas características de carcaça de bovinos de corte superjovens

Ninety-six young beef males were allotted to a completely randomized design in a 4x3 factorial scheme, four genetic groups, Nellore (N), ½ Simmental ½ Nellore (SN), ½ Red Angus ½ Nellore (AN) and ½ Red Angus ¼ Simmental ¼ Nellore (ASN), and three sex conditions (SC), intact (I), castrated (C) and castrated plus Synovex S ® implant (CS). Males were castrated at six months of age, and feedlot started two months later, with the animals being fed with a 70% chopped sugar cane : 30% concentrate diet. Steers were weighted with 28 days intervals, after 16 hours fastening, and were slaughtered with 13 to 15 month of age. The statistical analyses were performed with the MINITAB program. The effects of genotype (G), SC and G x SC on performance and carcass characteristics, were evaluated. Slaughter (SW) and hot carcass weight (HCW) were affected by G. The SN presented the highest SW (389.3 kg) and AN the lowest (343.1 kg). SC affected SW, HCW and finishing degree (FD). I and CS males were heavier at slaughter (373.8 and 375.2 kg, respectively) than C (341,2 kg). The lowest HCW was observed for C steers (180,6 kg), differing (P<.02) from I (197 kg) and CS (201,3 kg). CS steers showed better FD (2,17 points) than the other SC. The SC showed tendency (P< .07) to influence ribeye area, with CS steers showing larger area (65.2 cm2). The G x SC interaction was significant for average daily gain and carcass dressing percentage. When adjusted for initial weight, the interaction was significant for SW, and when adjusted for SW the interaction was significant for HCW. The Simmental crosses were heavier at slaughter. Castration at six months reduced the feedlot performance of young males. The Synovex S® implant increased the finishing degree of the castrated steers carcasses.

Spatialization of climate, physical and socioeconomic factors that affect the dairy goat production in Brazil and their impact on animal breeding decisions

Brazil has high climate, soil and environmental diversity, as well as distinct socioeconomic and political realities, what results in differences among the political administrative regions of the country. The objective of this study was to determine spatial distribution of the physical, climatic and socioeconomic aspects that best characterize the production of dairy goats in Brazil. Production indices of milk per goat, goat production, milk production, as well as temperature range, mean temperature, precipitation, normalized difference vegetation index, relative humidity, altitude, agricultural farms; farms with native pasture, farms with good quality pasture, farms with water resources, farms that receive technical guidance, family farming properties, non-familiar farms and the human development index were evaluated. The multivariate analyses were carried out to spatialize climatic, physical and socioeconomic variables and so differenciate the Brazilian States and Regions. The highest yields of milk and goat production were observed in the Northeast. The Southeast Region had the second highest production of milk, followed by the South, Midwest and North. Multivariate analysis revealed distinctions between clusters of political-administrative regions of Brazil. The climatic variables were most important to discriminate between regions of Brazil. Therefore, it is necessary to implement animal breeding programs to meet the needs of each region.

Valores de digestibilidade de alimentos volumosos para eqüinos

Quatro ensaios de metabolismo foram realizados para obter informacoes sobre os valores de digestibilidade dos nutrientes na alimentacao de equinos. Cavalos castrados, sem raca definida, com idade media de seis anos de idade foram usados. Nos experimentos foram testados: (1) cana-de-acucar, (2) combinacao de 59,0% de cana-de-acucar e 41,0% de milho grao inteiro, (3) capim-elefante e (4) cana-de-acucar com 1,5 % de ureia. O consumo medio de MS foi de 0,89; 1,11; 2,02; e 1,03% PV para cana-de-acucar, cana-de-acucar mais milho grao inteiro, capim-elefante e cana-de-acucar mais ureia, respectivamente. Os valores de energia digestivel para cana-de-acucar, cana-de-acucar mais milho grao inteiro, cana-de-acucar mais ureia e capim-elefante foram 2361, 3382, 2060 e 1182 kcal/kg MS, respectivamente. Cana-de-acucar e cana-de-acucar mais milho grao inteiro sao boas fontes alternativas de alimentos para os equinos. O capim-elefante e a adicao de 1,5% de ureia a cana-de-acucar apresentaram menor potencial nutricional como volumoso na alimentacao de cavalos adultos.

Analysis of longitudinal data of Nellore cattle from performance test at pasture using random regression model

This study was carried out to estimate (co)variance components and genetic parameters for live weight of Nellore cattle from Performance Test of Young Bulls using random regression models. Data of weights and ages of 925 weaned males was used. The animal model included the fixed effect of contemporary group, age of the animal at weighing as a covariate and as random effects it was considered the effect of additive genetic and permanent environment of the animal. The residue was modeled considering four classes of variances. The models were compared based on the Bayesian information criteria of Akaike and Schwartz. The model polynomial of fourth and sixth order for the direct additive genetic effects and permanent environment of the animal, respectively was the most appropriate to describe the changes in the variances of the weights during the period in which the animals participating in the performance test young bulls. Heritability estimates showed moderate magnitudes and indicated that direct selection will promote improvement of selection criteria adopted. Furthermore, due to high positive correlation between the estimated weights, it was suggested selecting the best animals before at 365 days of age, because it is the period in which the animals have a higher growth rate and thus you can select animals heavier and less delayed.

COMPOSIÇÃO BROMATOLÓGICA DA REBROTA DO MILHETO FORRAGEIRO: ALTURA DE CORTE RESIDUAL X INTERCEPTAÇÃO LUMINOSA

RESUMO: Portanto objetivou-se avaliar o efeito de quatro alturas de corte residual (ACR’s) associado a duas interceptacoes Luminosas (IL’s) sobre a composicao bromatologica da rebrota do milheto forrageiro. Houve diferenca (p<0,05) no percentual medio de materia seca, entre as IL’s e entre as ACR’s com IL de 90%. O teor medio de MS nas IL’s de 80 e 90% foi respectivamente de 14,13 e 17%. Em relacao a PB, houve diferenca (p<0,05) para o percentual de PB entre as medias das IL’s 80 e 90%, com 19,11% e 16,28% respectivamente. Houve diferenca (p<0,05), para a variavel EE entre as IL’s de 80 e 90%, com valores medios de 2,26 e 2,03% respectivamente. Os tratamentos com IL de 80% e ACR’s entre 30 e 40 cm, apresentam-se com a melhor composicao bromatologica da rebrota do milheto com excecao do teor de MS que teve os melhores resultados com 90% de IL.

COMPOSIÇÃO FIBROSA DA REBROTA DO MILHETO FORRAGEIRO EM FUNÇÃO DA ALTURA DE CORTE RESIDUAL E INTERCEPTAÇÃO LUMINOSA

Objetivou-se avaliar a composicao fibrosa da rebrota do milheto forrageiro em quatro alturas de corte residual (ACR) associadas a duas interceptacoes luminosas (IL’s) 80 e 90%. Os teores medios encontrados foram de 60,4 e 61,4% de FDN para as IL’s de 80 e 90% respectivamente. Nao houve diferenca entre os teores medios de FDA entre as IL’s. Houve diferenca (p<0,05) para os fatores ACR e IL na variavel celulose. Os teores medios de celulose nas IL’s de 80 e 90% respectivamente ficaram entre 26,83% a 27,75% da MS. Os tratamentos manejados com IL de 80%, tiveram os menores teores medios de constituintes da fibra em linhas gerais. Pensando nas caracteristicas quimicas - nutricionais da forragem, essa IL apresenta-se como um bom parâmetro de manejo para a rebrota do milheto. Ja em relacao ao fator ACR, so os resultados apresentados das variaveis estudadas neste trabalho, nao sao conclusivos para indicar uma ACR.