The fermentative, microbiological and nutritional dynamics of bovine colostrum fermented under anaerobic conditions at different temperatures is provided. Colostrum was homogenized and stored in PET bottles in anaerobic conditions and incubated at controlled temperature (32.5 ± 1°C or 22.5 ± 1°C) or at room temperature (17.4 - 21.5ºC) and opened after 0, 1, 7, 14, 21, 28 and 35 days to determine fermentative and nutritional parameters and bacteria, yeast and mold counts. Further, pH rates showed significant variations during the fermentation period (p < 0.0001), with colostrum stored at 32.5°C, exhibiting the lowest rates and significant reduction during the first days. Titratable acidity and lactic acid concentration showed increasing rates and LAB development was intense, especially at high temperatures. After 35 days, about 50% of total nitrogen became non-protein N and casein fraction was reduced to 0.66% of total nitrogen. Lactose decreased during fermentation and fat concentrations were not affected by temperature. Results suggested that the temperature at which the colostrum was fermented directly influenced the speed and intensity of microbial population development and degradation of the main nutritional parameters, such as casein and lactose.

RESUMO Vinte bezerros mestiços da raça Holandês x Jersey, distribuídos em blocos completos casualizados, foram utilizados para determinar o efeito do fornecimento de probiótico de bactérias ruminais sobre o desempenho e os parâmetros sanguíneos de bezerros leiteiros em sistema de desaleitamento precoce. Os animais foram submetidos ao tratamento controle ou ao fornecimento via oral de 2g de probiótico/dia durante o aleitamento. Os bezerros receberam 6 litros de sucedâneo lácteo por dia divididos em duas refeições diárias e foram desaleitados de forma gradual na 6ª semana de vida, entretanto, as variáveis foram coletadas até a 10ª semana. O consumo de concentrado inicial e o escore fecal foram registrados diariamente. Semanalmente foram realizadas pesagens e medidas corporais como, altura de cernelha, largura de garupa e perímetro torácico. Foram realizadas colheitas de sangue nas semanas, 2, 4, 6, 8 e 10, 2h após o primeiro aleitamento, para determinação de concentrações plasmáticas de glicose, proteína total, albumina, β-hidroxibutirato e cortisol. A suplementação de probiótico não afetou o consumo de concentrado, o peso, o ganho de peso, e as medidas corporais dos animais. Não houve efeito sobre o escore fecal entre os tratamentos. Os parâmetros sanguíneos não foram alterados em resposta ao fornecimento do probiótico, apenas a concentração de cortisol, que foi maior nos animais suplementados. O fornecimento de probiótico de bactérias ruminais não favorece o desempenho e o metabolismo de bezerros leiteiros em sistema de desaleitamento precoce.

This study aimed to evaluate the performance and metabolic changes in dairy calves supplemented with lysine and methionine in milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in Control without supplementation (1) and; Lysine and Methionine supplementation to achieve an intake of 17 and 5.3 g/d in the SC (2) and to achieve of 17 and 5.3 g/d in the MR (3). MR was fed (6 L/d) until the 8th week of life when weaning occurred. Calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly. Blood samples were collected biweekly to evaluate the intermediate metabolism. The AA supplementation resulted in lower body weight at weaning and week 10. Calves fed SC Lys:Met had lower SC intake and lower total feed intake at weaning when compared to control. Calves fed control had higher heart girth, hip-width, and plasma glucose concentration. The supplementation with Lys and Met did not benefit dairy calves’ performance nor metabolism in this study. Supplementation through the MR was more efficient than SC to result in adequate daily intakes of AA. Further studies are needed to understand the negative effects of AA on calf starter intake.

This study aimed to evaluate the performance and metabolic changes in dairy calves fed in a step-up/step-down program and supplemented with lysine and methionine in a milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in the control without supplementation (1) and with lysine and methionine supplementation in the SC to achieve an intake of 17 and 5.3 g/d, respectively (2), and in the MR to achieve the same daily intake (3). MR was fed 4 L/d until the 2nd week, 8 L/d from the 3rd to 6th week, and 4 L/d from the 7th to 8th week, when calves were weaned. The calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly, and blood samples were collected biweekly. The lysine and methionine intake during the whole period was higher when supplementation occurred via MR. There was a supplementation effect for average daily gain after weaning, and the animals supplemented in the MR had lower BW than those that were not supplemented. Supplementation in MR decreased starter intake at the 10th week and total intake (g DM/d) after weaning. Supplementation with lysine and methionine in the MR or the SC did not benefit the performance or metabolism of dairy calves in the step-up/step-down program. Further studies are needed to understand the effects of amino acid supplementation on feed intake.