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Effects of Milk Replacer and Multivitamin-Mineral Supplementation on Performance of Heat Stressed Dairy Calves
Seventy-one neonatal Holstein calves (40 female; 30 male) were used in a randomized block design with a 2x2 factorial arrangement of treatments to evaluate the effects of milk replacer (MR) alone or in combination with a multivitamin and electrolyte supplement on growth performance and mitigation of heat stress in southeast Louisiana. Milk replacer treatments consisted of Land O’Lakes Herdmaker Supreme (20% CP, 20% fat; CON) and Land O’Lakes Warm Front (27% CP, 10% fat; WF). Supplemented calves received either 0 or 20 ml Palamountains Calf Boost® (CB) in MR once daily in the morning feeding. Calves were offered MR treatments beginning on day 2, and all milk replacer was mixed at 15% solids. Calves consuming CON were fed 2.28kg MR twice daily. Calves on WF were fed 2.72kg MR twice daily for the first three weeks of life, and 3.86kg twice daily until weaning. Water and calf starter (20%CP) were offered ad libitum beginning on day 2. Beginning on day 42, MR feeding was reduced to 1 time per day for all treatment groups to decrease MR intake by 50%. On day 49 calves were weaned. Calves remained in their hutches until day 56 to determine immediate post weaning performance. Body weight, hip height, wither height, hip width, and body length were recorded weekly, and grain and water intakes were measured twice daily. Average rectal temperature, respiration rates, and fecal scores were recorded 3 times weekly at both 8AM and 4PM. All data were analyzed using the PROC MIXED procedure of SAS. There was a main effect of MR, with calves fed WF showing greater body weights and increased hip height, wither height, and body length (P<0.05). There was no significant effect of CB on growth or intake measurements. Calves fed WF consumed less grain than CON calves (P<0.05) until the end of week 7, but showed no difference at week 8. Calves consuming WF also showed higher fecal scores (P<0.05), but well within normal ranges for healthy calves. All calves consumed more water as age increased (P<0.05), with no interactions of sex or treatment. There was no significant effect of MR or CB on temperature or respiration rates (P>0.05). These data indicate that MR feeding management may improve growth performance in neonatal dairy calves, but multivitamin mineral supplements may not provide any additional benefit.
Keywords: calf milk replacer, multivitamin-mineral supplement, heat stress