Effect of Highly Purified and Commercial Grade Growth Hormone Preparations on Milk Production of Dairy Cows

The effect of injecting or infusing low doses of bovine growth hormone on milk yield, milk composition and the quantity of hormone in the milk serum of cows

“…The results obtained for the yield and concentration of milk fat, protein and lactose following treatment with bGH (30 u.g/kg daily) were similar to those obtained by others in that changes in the concentration of milk constituents were small in comparison to changes in their yields, which closely followed the increase in the quantity of milk (Donker and Petersen, 1952;Brumby and Hancock, 1955;Hutton, 1957;Bullis et al, 1965;Bines et al, 1980). Several groups have reported a tendency for the concentration of milk fat to increase and protein to decrease after injecting larger doses of bGH (Shaw, 1955;Bullis et al, 1965;Bines et al, 1980) and Peel et al (1983) have suggested that GHstimulated changes in milk composition may vary with the cow's energy status such that milk fat concentration is increased and protein concentration decreased when cows are in negative energy and nitrogen balance, but remain relatively unchanged when they are in positive energy balance.…”

“…The characteristics of the milk yield response to 30 fig/kg daily were the same as those obtained by others using higher doses of bGH administered over shorter periods (Bullis et al, 1965;Machlin, 1973;Bines et al, 1980;Peel, Bauman, Gorewit and Sniffen, 1981). The increase in yield took around 7 days to become fully established; the effect was maintained for the duration of the injection period and milk production returned to the predicted unstimulated level within 4 to 6 days of ceasing treatment (Brumby and Hancock, 1955;Machlin, 1973).…”

“…However, these results are not reliable since more recent work showed that the milk yield response to bGH takes up to seven daily injections to develop completely (Bullis, Bush and Bartos, 1965;Machlin, 1973). The present study examined, over a 3-week period, the milk production response of 12 cows to two doses of bGH which were lower than those used previously.…”

“…Several groups have reported a tendency for the concentration of milk fat to increase and protein to decrease after injecting larger doses of bGH (Shaw, 1955;Bullis et al, 1965;Bines et al, 1980) and Peel et al (1983) have suggested that GHstimulated changes in milk composition may vary with the cow's energy status such that milk fat concentration is increased and protein concentration decreased when cows are in negative energy and nitrogen balance, but remain relatively unchanged when they are in positive energy balance. The present data support this contention.…”

Embryo Manipulation in Research and Animal Production

“…Initially interest has been in the growth hormone gene because of the success of Palmiter et al (1982) and because it has been demonstrated that this hormone can increase growth rate and efficiency of growth rate, improve the muscle to fat ratio, and channel metabolism towards increased milk production in dairy cows (Brumby and Hancock 1955;Bullis et al 1965;Machlin 1972Machlin , 1973Moseley et al 1982). Transgenic livestock have been reported from severallaboratories and the most commonly used construct consists of a metallothionein promoter region fused to a structural growth hormone gene.…”