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ResumoObjetivou-se avaliar o efeito da contagem bacteriana total (CBT) sobre os constituintes do leite, verificando a influência que as variáveis climáticas exercem sobre a CBT. Os dados utilizados foram de 1.541 unidades produtoras de leite, referentes a 15 municípios da bacia leiteira do Vale do Taquari, Rio Grande do Sul. Foram tabulados os dados de CBT, contagem de células somáticas (CCS) e composição centesimal do leite, referentes ao período de junho de 2008 a dezembro de 2011, totalizando 44.089 amostras analisadas. As variáveis climáticas (médias mensais da temperatura média, da umidade relativa do ar e precipitação pluviométrica) não apresentaram correlação significativa com a CBT. Os teores de gordura, proteína, minerais e sólidos totais foram diretamente correlacionados com a CBT, enquanto os sólidos não gordurosos e a lactose apresentaram comportamento inverso. Através da análise de componentes principais (ACP), auxiliada pelo método hierárquico aglomerativo de agrupamento, os sete tratamentos presentes no estudo foram reduzidos a quatro grupos de acordo com a similaridade. Assim, os leites com CBT superiores a 50.000 até 500.000 UFC mL -1 , e ainda de valores acima de 500.000 até 1.000.000 UFC mL -1 apresentam a mesma qualidade química e contagem de células somáticas, não justificando a estratificação de intervalos nesta amplitude de variação para avaliação do efeito da CBT nestes indicadores de qualidade.Palavras-chave: composição química do leite, mastite, qualidade higiênico-sanitária do leite, variáveis climáticas. AbstractThe study aims to evaluate the effect of total bacterial count (TBC) on the milk constituents and the influence of the environmental conditions has on the TBC. Data were obtained from 1,541 dairy farms located in 15 municipalities in the dairy region of Vale do Taquari, Rio Grande do Sul. It was tabulated the data from TBC, somatic cell count (SCC) and milk composition, from June 2008 to December 2011, totaling 44,089 samples. The climatic variables have no significant correlation to TBC. The fat, protein, minerals and total solids were directly correlated with the TBC. While solids-not-fat and lactose showed an opposite behavior. Through of the principal component analysis (PCA), followed by agglomerative hierarchical clustering method, the seven treatments in the present study were reduced to four groups according to similarity, showing that milk with TBC above 50,000 to 500,000 CFU mL -1 and 500,000 to 1,000,000 CFU mL -1 , have the same chemical quality and SCC, not justifying the stratification intervals in this range of variation for evaluating the milk quality.Keywords: chemical composition of milk, climatic variables, mastitis, milk hygienic-sanitary quality. IntroduçãoO leite cru pode ser contaminado por grande variedade de micro-organismos provenientes de diversas fontes. Entre os micro-organismos patogênicos e/ou deteriorantes que podem ser encontrados, destacam-se as bactérias acidolácticas (Lactococcus, Lactobacillus spp., Leuconostoc, Enterococcus ou Streptococcu...

Bones from six different anatomical locations of two young, two intermediate and two old bovine were used to characterize bone marrow lipids as a function of animal age and bone location with the view of utilizing these lipids for human consumption. Nonpolar lipids from bone marrow increased with increasing animal age. Oleate was the predominant fatty acid in both nonpolar and polar lipid fractions. There was a decrease in the unsaturated fatty acids in nonpolar and polar lipids from young to old bovine. As chronological age advanced the percent of triglycerides in bone increased while the percent of cholesterol esters, cholesterol, free fatty acids and diglycerides decreased. Some changes in lipids as a function of anatomical location were evident.

Cervical, thoracic, lumbar and sacral vertebrae, plus rib and femur bones were removed from 13 bovine of a wide age range (89-2783 days) to elucidate changes in bone composition as a function of age and anatomical location. Percent dry matter, ash, calcium and phosphorus increased with age while nitrogen and sulfur decreased. The calcium/ phosphorus ratio remained relatively constant during growth. Dry matter, ash, calcium and phosphorus percentages increased from the anterior to the posterior of the vertebral column, while sulfur and nitrogen decreased. Thus, bone ossification advanced from the posterior to the anterior vertebrae. The femur contained the largest proportion of ash, calcium and phosphorus of the six bone types investigated.

The objective of this work was to identify the most suitable model for the genetic evaluation of post-weaning weight gain in a multibreed Angus-Nelore population. Three models were tested using the Bayesian inference method: traditional animal model (M1), multibreed animal model without (M2) and with segregation (M3). The choice of the best model followed the criteria: number of parameters (Np), deviance information criterion (DIC), conditional predictive ordinate (CPO), and deviance based on Bayes factors. Spearman’s rank correlations were estimated for the top 10, 20, and 30% sires. M1 presented the highest values for all criteria, except for Np, and the lowest direct heritability estimate of 0.15±0.01. The heritability estimates for M2 and M3 were higher and similar, being 0.29±0.02 and 0.27±0.02, respectively. M3 showed the lowest values for mean deviance, DIC, and CPO, being the best-fitting model among the three tested. Spearman’s correlation between the predicted genetic values for the models ranged from 0.69 to 0.99. The multibreed models are the most suitable for the genetic evaluation of multibreed populations, and M3 shows the best fit for the studied population.