-The objective of this study was to evaluate the nutritional and microbiological composition of colostrum samples collected from colostrum banks or newly calved cows on dairy farms. For this purpose, 66 colostrum samples from dairy cows were directly collected during the milking of newly calved cows or from colostrum storage bank. Samples were collected from commercial properties in the states of Minas Gerais, São Paulo, and Paraná -Brazil, which were classified according to the total daily milk yield (MY). Even though average immunoglobulin concentrations were either adequate (79.7 and 51.7 mg/mL, for farms with MY>701 L/d and <200 L/d, respectively) or marginal (48.1 mg/mL for MY between 201-700 L/d), for only 48.4% of the colostrum samples, immunoglobulin concentrations were greater than 50 mg/mL. A variety of factors such as production system, animal breed, and time of sample collection can also affect the variables studied. In addition to emphasizing nutrition, good hygiene practices during the colostrum collection and storage process also deserve attention, since 24% of colostrum samples were below the microbial quality parameters. When nutritional and microbiological quality were simultaneously analyzed, only 22.6% of colostrum samples met the recommendations. Therefore, most of the calves in this region of Brazil are likely to present failure of passive immunity transfer and are exposed to pathogens when fed maternal colostrum.

-The objective of this study was to evaluate the route of administration of mannan-oligosaccharides in the diet of dairy calves and their effects on performance and plasma parameters indicative of rumen development.Following birth, twenty-four male Holstein calves were used in a completely randomized design and assigned to the following treatments: Control; 4 g/d Bio-Mos ® (Alltech Biotech.) added to starter concentrate; and 4 g/d Bio-Mos ® mixed into milk replacer. Animals were housed in individual hutches with free access to water, and fed 4L/d of milk replacer until weaning at six weeks. Calves also received 23g/kg crude protein of starter concentrate ad libitum. Fecal scores were evaluated daily. Body weights, growth measurements and blood samples for glucose, urea-N and β-hidroxibutyrate analyses were taken weekly until 8 weeks of age. There were no significant effects of treatment or treatment × age interactions for mean starter concentrate intake, weight gain or body growth. However, there was a significant age effect for all parameters. Fecal scores were not affected by treatments. Also, plasma concentration of glucose, urea-N or β-hidroxibutyrate were not affected by treatment or the treatment × age interaction. However, urea-N and β-hidroxibutyrate concentrations significantly increased with age, suggesting adequate rumen development. Under the conditions of this study, there were no calf performance benefits when mannan-oligosaccharides were incorporated into milk replacer or calf starter concentrate .

SUMMARY Other than crude protein (CP), crude energy (CE) and crude fiber (CF) content, the adequate supply of essential amino acids (EAA) is an important factor in milk replacer evaluation. The aim of this study was to analyze milk replacer samples as regard to nutrients, especially EAA, composition and simulate the attainability of calves' requirements in different feeding systems. Forty-one milk replacer samples were collected from 14 brands and analyzed for nutrient composition. The near infrared spectroscopy technique was used for AA content estimation. Samples presented adequate levels of CP (21.2±2.90%) and ether extract (14.5±3.41%) for calves fed according to the conventional (4L/d), but not for intensive milk feeding system (>6L/d). High values of CF were observed in the samples (1.6±0.86%). The EAA composition of milk replacer samples was lower than expected for a liquid feed supposed to replace whole milk. None of the analyzed samples presented adequate lysine (5.72±1.09% CP) or methionine (1.65±0.38% CP) to meet calves' daily requirements, regardless of feeding system. Higher crude protein milk replacers are needed. Alternatively, supplementation of milk replacers with EAA is recommended.

No abstract

RESUMO Foram utilizados 24 bezerros que receberam 4L/dia de sucedâneo, além de livre acesso a água e concentrado até a 8a semana. Os animais foram distribuídos em delineamento de blocos casualizados, em dois tratamentos: 1) Controle: sem a suplementação de probiótico; 2) Suplementação de 2g/d de Bacillus subtilis e Bacillus licheniformis via sucedâneo lácteo. Semanalmente os animais foram pesados e foram aferidas as medidas corporais; também foram realizadas colheitas de sangue para determinação de glicose, proteína total, ureia e albumina, além de hematócrito. Foram colhidas amostras de fezes semanalmente para contagem de bactérias ácido láticas e enterobactérias e determinação de pH fecal. O peso corporal, o ganho de peso médio diário e as medidas corporais não foram alteradas pela suplementação; muito embora tenham apresentado efeito significativo de idade dos animais. O escore fecal, pH fecal e consumo de concentrado diário também não foram afetados pela suplementação. No entanto, o consumo de concentrado e o pH fecal sofreram influência da idade em resposta ao crescimento natural dos bezerros. A contagem de bactérias ácido láticas foi maior em número do que a contagem de enterobactérias durante todo o período. Apenas as enterobactérias sofreram efeito da idade, enquanto as bactérias ácido láticas permaneceram variando, porém dentro de um padrão constante. Os parâmetros sanguíneos também não foram afetados pela suplementação com probiótico mas todos, com a exceção da albumina, tiveram influência da idade. A suplementação com o probiótico não apresentou benefícios no desempenho ou no metabolismo de bezerros leiteiros, também não reduziu a ocorrência de casos de diarreia.