Effect Of Hormone In Legumes

Press, Volume CIV, Issue 30895, 30 October 1965, Page 9

Effect Of Hormone In Legumes

EXPERIMENTAL work on the research farm at Lincoln College involving the administration of a female sex hormone type of substance, oestrogen, to lambs and measurement of teat length has shown that in the spring there is a fairly high oestrogen level in white clover and at the same time the level in lucerne is fairly low, but in the autumn the position is reversed. Speaking to farmers at the college field day last week Dr. J. W. McLean, head of the veterinary department at the college, said it was the first time that it had been demonstrated in New Zealand that white clover contained oestrogens. “We need to know whether on the one hand the fast growth rate of lambs is due to the oestrogen content of the feed, and whether the level of the substance is high enough to influence the fertility of breeding sheep. “It appears in general from what we know of other countries that the levels reached could interfere with fertility if ewes were grazing herbage of this type long enough to bring about a disturbance in the breeding cycle.” This season Dr. McLean said that they would be wanting to find out how much oestrogen was needed to obtain a growth response. He said that one group of lambs would be given no oestrogen, another 12 units and another 48 units. It was anticipated that something like 48 units would give an increase in the rate of growth of lambs in the next few weeks.

In answer to a question Dr. McLean said it was not known whether the level of oestrogen in lucerne in the autumn would be sufficient to depress lambing percentage of ewes grazing on it. Professor I. E.

Coop had done some work which indicated that this could be so on the college’s Ashley Dene property. It was not known how long it would be safe to graze lucerne under these conditions and with the likelihood that areas of lucerne on particularly light land would increase information was needed to enable sound recommendations to be made in this respect. It was not suggested, he said, that a fast growth rate in lambs was due solely to oestrogen levels—it had been observed that such lambs were eating a lot more than those growing more slowly on grasses. It was unlikely that oestrogens were responsible for this.

in lambs was due solely to oestrogen levels—it had been observed that such lambs were eating a lot more than those growing more slowly on grasses. It was unlikely that oestrogens were responsible for this. At high levels of oestrogen where a growth rate response was obtained Dr. McLean said he thought that there would be a change in carcase composition with more water and less fat and a bit more bone and muscle.