Effect of Stage of Lactation, Age of Ewe, Sibling Status, and Sex of Lamb on Gross and Minor Constituents of Dorset Ewe Milk

Abstract

Samples of colostrum and milk were obtained from 27 Dorset ewes. Colostrum obtained within 24 h after lambing contained the following: protein 10.1%, fat 10.4%, lactose 2.9%, ash 0.9%, total solids 25.4% and energy 1683 cal/g. The average composition of milk for lactation (day 5, 28 and 56 postpartum) was as follows: protein 5.2%, fat 12.6%, lactose 4.8%, total solids 23.4%, ash 0.79%, energy 1631 cal/g, amino acids 997 g/kg milk protein; minerals, Ca 188 mg/dl, P 183 mg/dl, Mg 15.1 mg/dl, K 101 mg/dl, Na 132 mg/dl, Cu 1.3 ppm; Zn 11.8 ppm, Fe 1.9 ppm; fatty acids (14:0) 10.5, (16:0) 29.2, (16:1) 2.9, (18:0) 19.8, (18:1) 34.6, (18:2) 3.1% wt; cholesterol 61 mg/100 g; and vitamins, A 313 IU/dl, E 0.35 mg/dl, C 2.0 mg/dl, niacin 0.51 mg/dl, pantothenic acid 0.45 mg/dl, riboflavin 0.40 mg/dl, B6 0.07 mg/dl, B12 0.56 mg/dl, biotin 3.52 .mu.g/dl. Age of ewe, lamb sibling status and sex of lamb had no effect on nutrient composition of Dorset ewe milk. Many constituents were different for colostrum from milk. Daily milk yield by Dorset ewes averaged > 1000 g during the 1st mo. of lactation and decreased to 500 g during the 8th wk of lactation. Lamb growth and milk production by ewes were positively correlated during early lactation. Milk components were not significantly related to growth.