عنوان	Soybean oil supplementation and starter protein content: Effects on growth performance, digestibility, ruminal fermentation, and urinary purine derivatives of Holstein dairy calves
نوع پژوهش	مقاله چاپ‌شده در مجلات علمی
کلیدواژه‌ها	dairy calves, metabolizable protein, oil supplementation, fiber digestibility, microbial protein synthesis
چکیده	This study investigated the effects of feeding dairy calves starter diets containing 19% or 22% crude protein (CP) content on dry matter (DM) basis and either supplemented or not with soybean oil (SBO, 0 vs. 3%, DM basis) on growth performance, digestibility, urinary nitrogen, and purine derivatives (PD) excretion. A total of 48 female Holstein dairy calves (mean 39.8 kg body weight) were randomly distributed to experimental diets in a 2 × 2 factorial arrangement of treatments. The four dietary treatments were 1) starter diet without SBO supplement and 19% CP (NSBO-19CP), 2) starter diet without SBO supplement and 22% CP (NSBO-22CP), 3) starter diet with 3% SBO and 19% CP (SBO-19CP), and 4) starter diet with 3% SBO and 22% CP (SBO-22CP). Milk feeding value was similarly based on a constant protocol across experimental treatments and calves had ad libitum access to water and starter diets throughout the study. All calves were weaned on d 63 of age and remained in the study until d 83 of age. Calves supplemented with SBO had lower starter feed intake and average daily gain (ADG) and lower feed efficiency (FE) but had a higher fecal score indicating a higher likelihood of diarrhea occurrence compared with unsupplemented calves. Therefore, our results indicate that feeding the higher starter CP content is not a viable strategy to compensate for the negative effects of SBO supplementation on the growth performance of dairy calves.
پژوهشگران	صفورا یوسفی نژاد (نفر اول)، فرشید فتاح نیا (نفر دوم)، مهدی کاظمی بنچناری (نفر سوم)، حسن خانکی (نفر چهارم)، جیمز دراکلی (نفر پنجم)، مهدی غفاری (نفر ششم به بعد)