Abstract #M266

# M266
Effect of physical form and nutrient content of calf starter on growth and development.
David Vagnoni*1, Christine Sousa1, Jacqueline Aenlle1, Mike Messman2, 1California Polytechnic State University, San Luis Obispo, CA, 2Cargill Animal Nutrition, Elk River, MN.

One hundred twenty-eight Holstein heifer calves (37.7 ± 4.6 kg BW) were allotted to 4 diets to evaluate physical form and nutrient composition of starter feed on performance and development. Diets consisted of a typical texturized calf starter (Diet A), texturized calf starter with reduced grain and increased NDF (Diet B), standard texturized calf starter with increased sugar content (Diet C), or a completely pelleted, relatively high NDF diet (Diet D). Calves received colostrum at their dairy of origin (n = 7) before arriving at the commercial calf operation where the study was conducted. Upon arrival, calves were weighed and assigned to dietary treatments in an attempt to equalize initial BW and distribution of dairy of origin across treatments. Calves received 2 L of pasteurized dairy waste milk twice daily until 42 d of age. Milk offered was reduced to 1 L per day until d 49 when weaning was complete. Calves received ad libitum water and starter feed throughout the trial, at 70 d of age. Starter feed offered and refused was measured daily. Body weights were recorded every 7 d and blood samples were obtained for measurement of glucose and β-hydroxy butyrate at 28, 42, 56, and 70 d of age. Data for pre-weaning and post-weaning weight gain and feed intake were analyzed as a completely randomized design. Blood concentrations were analyzed using a mixed linear model with time as a repeated factor. Diet did not affect (P = 0.28) pre-weaning weight gain (overall average = 0.55 kg/d) but did (P = 0.047) affect post-weaning weight gain (overall average = 0.82 kg/d), with diets A and B performing better than diets C and D. Diet affected pre-weaning (P = 0.038) but not post-weaning (P = 0.9) starter intakes. Concentrations of glucose (overall average = 87 mg/dl) decreased (P < 0.01) and concentrations of β-hydroxybutyrate (overall average = 0.12 mM) increased (P < 0.01) as calves transitioned from milk to primarily solid feed intake, reflecting the development of ruminal fermentation. Results indicated that acceptable calf performance can be obtained with a variety of dietary carbohydrate formulations and that blood concentrations of glucose and β-hydroxybutyrate may be useful indicators of ruminal development and readiness for weaning.

Key Words: calf starter, rumen development