Effects of a hepatoprotectant and different feed energy sources on milk composition and nutrient partitioning in lactating cows / Efeitos de um hepatoprotetor e diferentes fontes de energia na dieta sobre a composição do leite e a partição dos nutrientes em vacas lactantes

The present study aimed at assessing the effects of hepatoprotective agents in diets that contain sources of energy on milk production, milk composition, and nutrient partition in lactating cows. Sixteen Holstein x Gir crossbred mid-lactation cows with an average body weight of 553 ± 85 kg were used in this study. These animals were allocated in a 4x4 Latin square design. A 2x2 factorial arrangement was employed in this feeding experiment. In each treatment, cows received diets with or without a hepatoprotective agent and variable in ground corn grain or citrus pulp as energy sources. Evaluated parameters included nutrient intake and digestibility, milk production, milk composition, energy balance, and nitrogen balance. Performance and nutrient balance variables were assessed and no interaction was observed between the hepatoprotective compounds and the dietary sources of energy. Dry matter intake, milk production and net energy for lactation were higher in corn as an energy source whereas milk fat content was higher in citrus pulp diets. There was a reduction in protein and casein contents in the milk of cows that was supplemented with an hepatoprotective agent. In this study, the hepatoprotective agent improved nitrogen balance in dairy cows. The use of the hepatoprotective compounds in the diet of these lactating cows in confinement reduced the milk protein fraction and favored a higher nitrogen balance in these animals. Retention of nitrogen compounds in the metabolism of lactating cows under confinement is influenced by hepatoprotective agents.(AU)

Objetivou-se com este estudo avaliar os efeitos de fontes de energia associadas a um hepatoprotetor sobre a produção, composição do leite e a partição dos nutrientes em vacas lactantes confinadas. Foram utilizadas 16 vacas mestiças Holandês x Gir no terço médio da lactação, com peso corporal médio de 553 ± 85 kg, distribuídas em delineamento experimental quadrado latino 4x4 quádruplo em arranjo fatorial 2x2. Os tratamentos consistiram de dieta com ou sem a inclusão do hepatoprotetor, e variação de milho moído ou polpa cítrica como fontes de energia. Não houve interação (P>0.05) entre as fontes de energia e o hepatoprotetor para as variáveis de desempenho e balanço de nutrientes. O consumo de matéria seca, a produção de leite, o leite corrigido para 4% de gordura foram maiores (P<0.05) nas dietas com milho moído como fonte de energia. O teor de gordura do leite foi maior (P<0.05) nas dietas com a polpa cítrica. Houve redução (P<0.05) no teor de proteína bruta e caseína no leite das vacas que receberam o hepatoprotetor na dieta. O hepatoprotetor favoreceu maior (P<0.05) retenção e balanço de nitrogênio nas vacas. Portanto, o milho moído pode ser utilizado na dieta como fonte de energia para impulsionar a produção de leite. Enquanto, a fonte de energia proveniente da polpa cítrica afeta a composição do leite, através do incremento no teor de gordura. O uso de hepatoprotetores na dieta favoreceu maior retenção de nitrogênio em vacas lactantes confinadas.(AU)

Metabolic status of lactating cows given a hepatoprotectant and different feed energy sources.

The present study aimed to evaluate the effects of hepatoprotective agents added to diets containing different energy sources on the metabolic status of lactating dairy cows in confinement. Sixteen Holstein × Gir crossbred midlactation cows with a body weight of 553 ± 85 kg were included in this feeding trial. These animals were arranged in a 4 × 4 Latin square experimental design. A 2 × 2 factorial arrangement was employed in this feeding experiment. Experimental treatments consisted of the administration of diets supplemented with a hepatoprotectant and diets without hepatoprotectant. These diets contained varying amounts of ground corn or citrus pulp as energy sources. Serum markers for energy metabolism and proteins were evaluated and liver enzymes were measured. Blood samples were collected in the morning before (0 h) and 4 h after the animals were fed these diets. There was no interaction between the hepatoprotective agent and the dietary energy sources for the metabolic status variables. Ground corn as an energy source yielded higher serum concentrations of glucose, HDL (high-density lipoprotein) cholesterol, and globulins, whereas b-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), total cholesterol, albumin, and aspartate aminotransferase (AST) yielded the highest concentrations in diets containing citrus pulp. There was interaction between time and hepatoprotective agent in serum LDL (low-density lipoprotein) cholesterol concentration. The present study shows that ground corn diets increased the synthesis of glucogenic nutrients, whereas citrus pulp used as an energy source altered the lipid status of lactating cows. The hepatoprotective agent increased postprandial serum LDL cholesterol levels.

Spineless cactus use management on microbiological quality, performance, and nutritional disorders in sheep.

The physically effective neutral detergent fiber content alone has not been able to explain the appearance of diarrhea in ruminants fed diets with large volumes of spineless cactus, so the proliferation of enterobacteria in spineless cactus may be associated with cases of diarrhea in sheep. In the in vitro test, used two varieties of spineless cactus, both of which were chopped to particles of 4 and 2 cm2. For the in vivo test, 15 lambs were allocated to three treatment groups, namely, spineless cactus crushed and immediately supplied to the animals; spineless cactus crushed 8 h before supply; and silage of spineless cactus. The variables evaluated were dry matter intake, weight gain, fecal score, hemogram, and fecal colony count. In the in vitro test, higher Enterobacteriaceae and lactic acid bacteria counts were found both at 12 h and 24 h when the spineless cactus was crushed to 2 cm2 in both varieties. The sheep fed the spineless cactus crushed 8 h prior to supply showed the highest Enterobacteriaceae count in the feces (8.48 CFU/g), compared to animals fed silage of spineless cactus (4.95 CFU/g). It can thus be concluded that the management of spineless cactus influences the development of total and fecal coliforms, especially when it is chopped to 2 cm2 and exposed to the environment for periods longer than 7 h, and that the bacterial population can be controlled by administering the spineless cactus in the form of silage.