Soybean oil supplementation and starter protein content: Effects on growth performance, digestibility, ruminal fermentation, and urinary purine derivatives of Holstein dairy calves

This study investigated the effects of feeding dairy calves starter diets containing 19% or 22% crude protein (CP) content on a dry matter basis and either supplemented not with soybean oil (SBO, 0 vs. 3%, basis) growth performance, digestibility, urinary nitrogen, purine derivatives (PD) excretion. A total 48 female Holstein (mean 39.8 kg body weight) were randomly distributed to experimental in 2 × factorial arrangement treatments. The 4 dietary treatments (1) diet without SBO supplement CP (NSBO-19CP), (2) (NSBO-22CP), (3) 3% (SBO-19CP), (4) (SBO-22CP). Milk value was similarly based constant protocol across had ad libitum access water throughout study. All weaned d 63 age remained until 83 age. Calves lower feed intake average daily gain (ADG) efficiency (FE) but higher fecal score indicating likelihood diarrhea occurrence compared unsupplemented calves. Wither heights, digestibilities organic matter, CP, neutral detergent fiber decreased, ruminal volatile fatty acids tended be reduced, molar proportion butyrate (preweaning) acetate (postweaning) reduced by supplemental SBO. allantoin PD excretion reduced; however, nitrogen increased when amount did affect intake, FE, rate, whereas 22CP improved ADG (tendency), 19CP diets. ADG, nutrient fermentation affected interaction between level; hip height that received SBO-22CP than those fed SBO-19CP In conclusion, our conditions, could recommended for Furthermore, findings indicate has negative performance more attributed reducing acid concentration rather because limitation metabolizable supply intestinal amino availability. Therefore, results is viable strategy compensate supplementation