Health and growth of Holstein calves fed blends of yeast products, phytogenics, and direct-fed microbials in milk replacers and pelleted starters

The use of yeast products, phytogenics, and direct-fed microbials (DFM) have been shown to improve health and growth performance of dairy calves. More recently, combining nutrients and additives to optimize calf performance has become a growing interest area. The purpose of this study was to determine if feed additives in milk replacer (MR) and starter could improve health and growth of Holstein calves through 13 wk of age. Ninety male Holstein calves <4 d of age were assigned to 1 of 3 treatments. Calves were individually housed in outdoor hutches through d 56, then moved to group pens through d 92. Treatments were a control MR and pelleted starters with no additives (CON); a MR with phytogenics and yeast extract plus a starter with a blend of phytogenics and yeast products (CTP); and the same CTP MR with a starter containing an experimental blend of phytogenics, yeast products, and DFM (CEP). Diets were formulated as follows: MR contained 22% CP and 20% fat and starters contained at least 16% CP and 4% fat (as-fed basis). Average initial BW and SD were 42.1 (±5.9) kg for CON, 42.9 (±4.9) kg for CTP, and 43.3 (±5.5) kg for CEP. Calves were fed MR at a rate of 600 g/d (as fed), reconstituted to 13% solids. This amount was fed from d 0 to 42 when the single step-down weaning process started by discontinuing the evening MR feeding. After d 49, MR was completely discontinued but calves stayed in individual hutches through d 56 and then were moved to group housing. During the group-housed portion of the experiment, calves were provided with ad libitum pelleted starters and water. Health scores were collected twice daily from d 1 to 56, and once daily from d 57 to 70. Body weight and frame measurements were collected weekly. Average ME intake was consistently greater for CTP throughout the trial, and starter ME intake was greater compared with CON for wk 4 to 13. Final BW was greater for CTP and CEP for wk 1 to 13 relative to CON. Frame growth was improved for CTP and CEP during wk 1 to 8 in comparison to CON. Feed efficiency tended to be greater for CTP and CEP compared with CON during wk 9 to 13. There was a tendency for lower incidence of scours for calves fed CTP, and overall health and need for medication were improved for calves fed both CTP and CEP compared with CON. Results of this study indicate improvements in pre- and postweaning health and growth of calves fed blends of yeast products, phytogenics, and DFM in MR and pelleted starters.