HORMONAL INDUCTION OF LACTATION IN DAIRY-CATTLE - MAJOR MILK CONSTITUENTS, AND ESTRADIOL AND PROGESTERONE LEVELS IN SERUM AND MILK

Six infertile cows, 42 to 96 months old and weighing 231 to 398 kg, we re administered oestradiol 17 beta (0.1 mg/kg b w a day) and progester one (0.25 mg/kg b w a day) in 2 divided doses, for 7 consecutive days. Reserpine (5 mg/animal a day) was injected on days 8,10,12, and 14, a nd dexamethasone (20 mg/animal/day) on days 18, 19 and 20. Lactation w as induced between days 9 and 14. Initially the secretion was watery a nd yellowish, by day 21 it appeared like normal milk. The average dail y milk yield between days 21 and 35 was 3.54 +/- 0.44 kg. Lactose incr eased from 4.67 +/- 0.13 g% to 5.19 +/- 0.47 g% while protein content decreased from 5.85 +/- 0.47 g% on day 21 to 3.45 +/- 0.14 g% on day 3 5. The concentration of fat and ash did not change significantly over this period. Oestradiol and progesterone levels in blood serum samples were 1036 +/- 313 pg/ml and 1270 +/- 501 pg/ml, respectively, on day 21 the levels declined to 708 +/- 154 pg/ml and 180 +/- 26 pg/ml by da y 35. The levels of oestradiol and progesterone in milk during the 15 days sampling period averaged 118 +/- 5pg/ml (range 79 to 149 pg/ml) a nd 550 +/- 37 pg/ml (range 372 to 804 pg/ml) respectively. The levels of oestradiol, progesterone and other milk constituents in milk were c omparable to those observed in 8 normally lactating cows. This study s uggested that treatment with hormones is a viable method of inducing l actation in infertile cows. The quantity and quality of the induced mi lk were comparable to that of normal lactating animals in Indian condi tions.