Affiliation:
1. Department of Veterinary Medicine, School of Veterinary Medicine Rakuno Gakuen University Ebetsu Japan
2. Department of Sustainable Agriculture, College of Agriculture, Food and Environment Sciences Rakuno Gakuen University Ebetsu Japan
3. The National Federation of Dairy Co‐operative Associations (ZEN‐RAKU‐REN) Shinjuku Tokyo Japan
4. Department of Animal and Bioscience University of Guelph Guelph Ontario N1G2W1 Canada
Abstract
AbstractThe objective of this study was to investigate the effects of calf starters with different starch content on rumen and blood properties in calves fed under a high plane of nutrition program. Twenty‐seven Holstein calves (14 female, 13 male) were assigned to one of three starter treatment groups in a randomized block design: high‐starch (41.8%) (n = 9), H; medium‐starch (31.9%) (n = 9), M; low‐starch (22.0%) (n = 9), L. Milk replacer on powder basis was fed up to 1.2 kg/day as fed, gradually reduced from 6 weeks of age; calves were weaned at 8 weeks of age. Each starter (up to 3.5 kg/day as fed) and chopped hay were provided ad libitum from 5 days of age. Blood was collected from 4 to 13 weeks of age. Rumen fluid was collected at 6, 8, 10, and 13 weeks of age. Serum urea nitrogen concentration after weaning was the lowest in H. Plasma IGF‐1 concentrations were higher in H than in L. Ruminal pH was not different, but the molar proportion of ruminal propionate was higher in H than in L throughout the study period. In summary, a high‐starch starter may increase propionate production and microbial protein synthesis in the rumen, inducing higher plasma IGF‐1 concentrations.