Composition of Percheron Mares' Colostrum

Abstract

Thirty samples of colostrum were collected for the first 6 days of lactation from 4 normal, purebred Percheron mares. Their ages varied from 4 to 11 years, their weights from 1600 pounds to 1900 pounds, and their lactation periods being from the first to the 6th. One mare was used for two lactation periods, her 5th and 6th. The water content of the colostrum was similar for the different mares. The mean protein values for the 6-day period, which ranged from 3.7% to 5.4%, were markedly higher than the value of 2.3% reported for mature mares' milk. Relatively small amounts of reduced ascorbic acid were found, i.e., from 47 mg to 66 mg per liter for mares that later produced mature milk which contained from 134 mg to 171 mg per liter. Initial samples of colostrum contained less phosphorus than the later samples. The mean values in milligrams per liter of 86, 75, 79, 85 and 83, were higher than the 63 mg per liter obtained in an earlier study of mature milk. The mean values for potassium for the different mares were 101 mg, 80 mg, 80 mg, 100 mg, and 94 mg per liter as compared with 64 mg per liter for mature milk. The various samples of colostrum contained similar amounts of magnesium. The mean values were significantly higher than those previously obtained for milk produced at the end of the first month of lactation. Values obtained for colostrum produced during two lactation periods of the same mare were in close agreement.