Colostrum components and their impact on digestive function and growth of dairy calves

by Kehoe, Sylvia I.

Colostrum is the first important step in raising healthy dairy calves. Feeding of adequate volumes of colostrum within the first 2 hours after birth improves calf health, immunity and productive lifespan. Two experiments were conducted, the first was to evaluate and record colostrum management and nutrient composition to determine any improved or deleterious changes. The second was to evaluate the effects of a particular component of colostrum, nucleotides, on enhancing absorptive capacity and decreasing diarrhea in neonatal dairy calves. For the first experiment, data and samples were obtained from 55 farms around the state of Pennsylvania. Samples were analyzed for fat, protein, lactose, total solids, ash, immunoglobulins, lactoferrin, water- and fat-soluble vitamins and minerals. Results of means of fat, protein, lactose and lactoferrin were as follows: 6.7%, 14.92%, 2.49% and 0.82 mg/ml, respectively. Immunoglobulin G1, G2, A and M were 35.1 ± 11.9, 5.6 ± 1.9, 1.7 ± 0.9 and 4.3 ± 2.8 g/L, respectively. Fat-soluble vitamins included retinol, tocopherol and B-carotene and were 4.9, 2.92 and 0.68 ug/g, respectively. Means of water-soluble vitamins were 0.34, 0.90, 4.55, 0.60, 0.15, 0.21 and 0.04 for niacinamide, thiamine, riboflavin, cyanocobalamin, pyridoxal, pyridoxamine and pyridoxine, respectively. Means of minerals (mg/kg) consisted of calcium 4716.08; phosphorus 4452.12; magnesium 733.24; sodium 1058.93; potassium 2845.89; zinc 38.10; iron 5.33; copper 0.34 and manganese 0.10. In comparison to previous reviews of bovine colostrum, most nutrient levels have increased. Management practices have also improved in areas of colostrum storage and feeding. Calves were fed by bottle in 85% of farms and only 1 farm allowed calves to nurse the dam. Calves were fed first colostrum within 6 hours of birth in 95% of farms and 38% of farms had a supply of frozen colostrum readily available for use. For the second experiment, to analyze for effects of feeding purified or yeast derived nucleotides, calves were fed milk replacer at 10% of BW daily and treatments consisted of no nucleotide supplementation (C), purified nucleotide supplementation (N) and yeast supplementation (P; Alltech, Inc.). Growth, health, fecal dry matters and fecal bacteria were monitored and blood was analyzed for hematocrits, glucose, blood urea iii nitrogen and creatinine. After the second day of scouring, xylose (0.5 g/kg of BW) was administered orally once and blood was taken before administration for a baseline as well as 1, 2, 3 and 4 h post-dosing. Concentrations of plasma xylose increased with time postdosing, but did not vary by treatment. Hematocrits were significantly higher for treatment N for weeks 2 and 5. Growth parameters and plasma concentrations of glucose, BUN, creatinine and IgG were not different between treatments. There were also no treatment effects on fecal dry matters and concentrations of fecal bacteria. Intestinal parameters, including morphology, enzyme activities, DNA and protein concentrations were not significantly affected by nucleotide supplementation. Calves supplemented with purified nucleotides had higher hematocrits, higher bacterial concentrations of Clostridium in feces and similar xylose absorption to control calves. Calves supplemented with yeast-derived nucleotides had increased xylose uptake 4 hours after dosing, highest Lactobacilli and Bifidobacteria concentrations in feces but a higher ratio of BUN to creatinine indicating higher dehydration. Dietary supplementation of nucleotides did not appear to enhance any growth, health or metabolic parameters in this model. More research needs to be conducted to investigate optimal concentrations of supplemented nucleotides as well as method and time of administration. Neonatal calf diarrhea is a persistent problem on dairy farms. Education for improved colostrum management and feeding needs to be developed and consistently presented to producers to improve calf health and management. More research also needs to be conducted to determine optimal levels and methods of feeding of nucleotides in order to decrease calf morbidity and mortality in the first weeks of life. iv v