Efficacy of colostrum replacer versus maternal colostrum on immunological status, health, and growth of preweaned dairy calves.

 Colostrum supplies essential nutrients and immune supporting substances to the newborn calf. Additionally, to achieve successful passive transfer of immunity to the young calf is paramount. This is accepted as being more than 10 mg of immunoglobulin (IgG) per mL of serum and to achieve that, a calf should receive at least 150 to 200 g of IgG within two hours of birth. In practice, this means feeding 3 to 4 L of high-quality colostrum of more than 50 mg of IgG per mL. Further recommendations for high-quality colostrum are that it should have a total bacteria count (TBC) of less than 100,000 cfu per mL and a coliform count (CC) less than 10,000 cfu per mL. When colostrum quality is poor or unavailable, or for managerial convenience, or to ensure quality consistency at first feeding, or in disease control or eradication, commercially available colostrum replacers may be an alternative. The question is whether they are as effective as maternal (natural) colostrum. This was investigated by Dr Dr A. Lago and co-workers, the results of which they published in the Journal of Dairy Science, Volume 101 of 2018, page 1344 to 1354. The title of their paper is: Efficacy of colostrum replacer versus maternal colostrum on immunological status, health, and growth of preweaned dairy calves. 

The objective of their study was to compare the efficacy of feeding First Day Formula (Accelerated Genetics, Baraboo, WI) commercial colostrum (CR) with maternal colostrum (MC), using the  immunological status, growth and health of preweaned dairy calves as parameters. A total of 1220 Jersey and Jersey × Holstein calves were assigned after birth to receive either CR or MC. Calves assigned to MC were tube fed 2.8 L of MC and calves assigned to CR were tube fed a total of 500 g of CR (150 g of IgG) mixed into 1.9 L of water at one hour, 5 minutes after the calf was born.

Although both coliform count and total bacteria count were low for MC and CR treatments during the study, the predicted probability of calves receiving contaminated liquid feed (coliform count more than 10,000 cfu per mL) at first feeding was reduced for calves fed CR (1.5%) compared with calves fed MC (6.1%). The mean blood concentration of IgG was lower for calves fed CR than for calves fed MC (19.6 vs. 23.4 mg per mL). However, the apparent efficiency of absorption of IgG did not differ between treatments (34.4 and 35.9% for CR and MC, respectively). Total proteins were lower in calves fed CR compared with MC at 24 hours (5.16 versus 5.84 g per dL, respectively). Calves fed CR were 1.5 kg lighter at weaning and gained 0.03 kg less per day (0.30 versus 0.33 kg per day, respectively) than calves fed MC before weaning. Height at weaning did not differ between treatments. Calves fed CR tended to have a higher predicted probability of not being treated for diarrhea than calves fed MC (0.142 vs. 0.110, respectively). However, when the disease was present, CR had a higher number of treatment days compared with MC (11.6 vs. 10.8 d, respectively).  

Conclusions drawn from the study were: Absorption of IgG and serum concentration of calves were adequate when fed either CR or MC, although calves fed CR had slightly lower  serum IgG and total protein concentration, lower ADG and were marginally lighter at weaning. The probability that a calf received contaminated liquid feed at first feeding was reduced for calves fed CR compared with calves fed MC and they performed similarly in terms of health. Use of CR may result in less exposure to bacterial contamination in early life. Therefore, the CR evaluated in this study appears to be a valid alternative to MC, but future work is needed to assess the long-term effects of early-life CR feeding.