Prepartal wheat grain feeding improves energy and calcium status of periparturient Holstein heifers

Wheat grain (WG) is unique in possessing extensive starch and nitrogen fermentation (i.e. >85% in ground and steam-processed WG), low cation-anion difference and high-intake properties, making it a potentially useful prepartal dietary choice. The objective was to determine the effects of WG provision to pre-partum first-calf heifers on metabolic, health and productive criteria during the transition period. WG replaced barley grain that was commonly used earlier. Fifteen Holstein heifers at 31 ± 6 days pre partum were blocked based on expected calving date and assigned to three treatments or feeding totally mixed rations containing either (i) barley grain (13.8%) and wheat bran (6.1%), (ii) 10% WG (WG10) or (iii) 18% WG (WG18; dry matter (DM) basis) from 31 days pre partum until calving. In replacing WG for barley grains, some changes in WG use and slight changes in soybean and cottonseed meals use were made to properly formulate balanced rations for net energy for lactation, CP, calcium and P. Prepartal diets contained no supplemental anionic salts. Cows were monitored until 21-day post partum and received the same early lactation diet. The prepartal provision of WG and related dietary changes reduced urine pH at 7-day pre partum, and elevated blood calcium and glucose at 7-day pre partum and at 3-day post partum. Milk fat and protein yields were increased during the 21 days post partum by prepartal WG provision and related diet changes. Blood albumin, globulins, total proteins and urea concentrations were similar among treatments. Feeding diets with WG did not affect body condition score, calving difficulty, calf weight, placenta weight and the time interval from calving to placenta expulsion. It is suggested that prepartal provision of WG with necessary dietary changes led to simultaneous improvements in energy and calcium status of the heifers experiencing their first periparturient phase without compromising parturition status.