Effect of offering a second colostrum feeding and delivery method on transfer of passive immunity, health, and behavior in neonatal calves.

Our objective was to describe the effect of providing a second feeding of maternal colostrum (MC) or colostrum replacement (CR), using either an esophageal tube or nipple bottle delivery method, on transfer of passive immunity, and on measures of calf health and behavior during the first 3 d of life, as compared with providing a milk replacer control. Eligible newborn dairy and dairy x beef calves on a commercial Minnesota dairy were weighed, placed in a bedded pen, then fitted with a tri-axial accelerometer. All calves were tube-fed a first feeding of pooled heat-treated MC (average IgG = 84 ± 10g/L; μ ± SD) approximately one hour after birth, with smaller calves (27.3-36.3 kg) receiving 2.85L and larger calves (36.4-52.3 kg) receiving 3.8L. Calves (n = 31/group) were then randomly assigned to the second colostrum feeding, delivered 8 ± 0.2 h after the first feeding: milk replacer by bottle (MRB; 1.9L MR), MC by bottle (MCB; 1.9L of MC with 57.7 ± 6.5 g/L IgG), MC by tube (MCT; 1.9L of MC with 58.9 ± 6.3 g/L IgG), CR by bottle (CRB; 1L CR with 100g/L IgG), or CR by tube (CRT; 1L CR with 100 g/L IgG). For bottle fed calves, the bottle was offered for 15 min with refusals (mL) recorded. Venous blood samples were collected at 0, 8, and 24h for serum IgG measures (g/L) using RID analysis. MC samples from the first and second feeding were collected and frozen for IgG analysis. Calf health was evaluated through daily health scoring by study technicians, as well as farm-reported treatments. Behavior was continuously collected over the 72 h. Voluntary intake of milk replacer (mL) was recorded for all calves at the first milk bottle feeding provided the morning after enrollment. The effect of treatment on serum IgG at 24h was evaluated with linear models, and on refusals and farm reported treatments with logistic models. The effect of treatment on daily health scores and behavior was evaluated with repeated measures models. We observed very high and similar serum IgG concentrations at 24h among all treatment groups (g/L, MRB - 37.8 ± 1[μ ± SE]; MCT - 39.0 ± 1; MCB - 38.4 ± 1; CRT - 39.3 ± 1; CRB- 37.7 ± 1). We observed no difference among treatments for recorded health outcomes. Fewer calves in the CRB group refused > 25% of their first milk feeding (16.3%) compared with MCB (51.2%) or MRB (58.0%) the morning following enrollment, with no other appetite differences observed among groups. Transient differences in behavior were observed such that bottle fed calves stood longer and took more steps around feeding compared with tube fed calves. Under the conditions of this study, a second feeding of MC or CR at 8 h did not improve 24 h serum IgG, but no evidence of short-term adverse effects on measured health or behavior outcomes were detected.