No effect of a dietary zinc proteinate on clinical mastitis, infection rate, recovery rate and somatic cell count in dairy cows
1997
Whitaker, D.A. | Eayres, H.F. | Aitchison, K. | Kelly, J.M.
Forty dairy cows, paired at drying off according to expected calving date, milk somatic cell count (SCC) and previous mastitis history, and 10 heifers, paired by date of expected calving, were fed diets in the last 3 weeks of pregnancy which contained either 200 mg zinc proteinate and 60 mg inorganic zinc (Zinc group), or 260 mg inorganic zinc (Control group) per day in addition to the natural content of their feeds. After calving, the Zinc group each received 250 mg zinc proteinate and 140 mg inorganic zinc and the Control group 390 mg inorganic zinc per day above background levels. During the first 100 days of lactation there were no significant differences between the groups in terms of clinical mastitis rates, mastitis caused by environmental organisms, new infection rates or recovery rates. SCC showed no differences between the groups. Monitoring of body condition score and weight change, milk yield, blood metabolite values and fertility showed satisfactory and similar nutrition and productivity in both groups. The trial did not demonstrate any advantages from feeding proteinates to dairy cows and highlights the general absence of published controlled trial data on the subject.
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