| Abstrakt: |
Introduction: Several studies have explored the impact of diet type on energy sources. The current study aimed to evaluate the impact of feeding glucogenic versus lipogenic diets to Holstein dairy cows during the close-up period on cows' performances and their calves' growth parameters. Materials and methods: Twenty-four Holstein dairy cows with an average parity of 3 selected for the study, starting 21 days before expected calving. The cows were divided into three groups based on a randomized complete block design including a control diet (glucogenic diet, Glu), a low lipogenic diet (Llip) with 25% barley grain replaced by beet pulp, and a high lipogenic diet (Hlip) with 50% barley grain replaced by beet pulp. Daily recording of dry matter intake (DMI) was conducted, with blood samples collected on the day of parturition in cows and days 1, 2, 7, and 21 of calves age. In dairy cows, both the quality and quantity of colostrum were determined. Additionally, performance variables including feed intake, average daily gain, and skeletal parameters such as shoulder height, hip height, and body length were measured. Blood parameters, such as glucose, triglyceride, and concentrations of certain liver enzymes, including alkaline phosphatase (ALP), serum glutamic-pyruvic transaminase (SGPT), and serum glutamate oxaloacetate transaminase (SGOT) were recorded. Results: The increase of beet pulp in the prepartum diet led to a significant increase in DMI. Colostrum yield and constituents (protein, lactose, and solids nonfat percentage) decreased with an increase in beet pulp level and the differences between Glu and Hlip were significant. Performance parameters of the calves were similar across all treatments, except skeletal growth. Calves that were fed the Hlip diet showed a lower shoulder height compared to those fed the Glu diet. Blood glucose was significantly higher in cows and their offspring that were fed Llip diets compared to other groups. The concentration of liver enzymes, including ALP, SGPT, and SGOT was not affected by treatments. Conclusion: Substituting barley grain with beet pulp as a lipogenic component may enhance dry matter intake in periparturient dairy cows. However, it did not show a notable impact on offspring performance. [ABSTRACT FROM AUTHOR] |
