Master of Science (MS)
School of Animal Science
Twenty-four male Holstein calves (BW = 38.78 ± 7.26 Kg) were used to evaluate the effects of commercially available or farm mixed starter on animal performance, blood metabolites, and rumen health. Calves were randomly assigned to one of two treatments which included: commercial calf starter (minimum 20% CP; CCS) and starter of similar nutrient content but hand mixed on farm (FMS). Calves were offered treatments ad libitum on days 4 through 84. Milk replacer (MR) was offered beginning on day 4. On day 42, MR was reduced to once daily to decrease intake by 50%. On day 49 calves were weaned but remained in hutches for the remainder of the 84 d trial. Body weight (BW), hip height, withers height, hip width, and body length were recorded weekly, and grain and milk replacer intakes were measured twice daily. Rumen fluid and blood samples were collected every two weeks beginning on week 2 for analysis of ruminal pH, ammonia (NH3), volatile fatty acids (VFA), plasma urea nitrogen (PUN), plasma glucose, and â-hydroxybutyrate (BHBA). There was a treatment by week interaction (P < 0.05) for BW, starter intake and PUN. Postweaning BW was greater (P < 0.05) for calves fed FMS. Calves fed FMS had higher (P < 0.05) overall ADG. However, there were no differences (P > 0.05) on ADG before weaning. There were no treatment effects (P > 0.05) on structural growth variables, feed efficiency, and fecal scores. Calves fed FMS had greater (P < 0.05) starter intake. There were no treatment effects (P > 0.05) on total VFA concentrations, VFA molar percentages, glucose, and BHBA. Ruminal pH was higher (P < 0.05) for calves fed FMS while ruminal NH3 concentrations were greater (P = 0.03) for calves fed CCS. Calves fed CCS had greater (P < 0.05) PUN concentrations. These data suggest that farm mixed diets can equal commercial calf diets for general performance and rumen development when calf starter meets all the nutrient necessary for normal growth and is properly mixed.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Orellana Rivas, Ruth Marisol, "Effects of Calf Starter Composition and Mixing Method on Growth and Rumen Health in Young Dairy Calves" (2016). LSU Master's Theses. 579.