BREEDING FLOCK

New Zealand Herald, Volume LXXV, Issue 22948, 28 January 1938, Page 16

BREEDING FLOCK

nv H.B.T.

USE OF TWO-TOOTHS

SECURING BEST RESULTS

BENEFITS TO BE GAINED

Both the sheepmen anil dairy fanner are frequently faced with the prob-

.Hi in leculing v.licthej then torn emale stuck is sufficiently de\elop< it tlic general!* 'l'-centcrl age for tu;""

ing to I)e included in the breeding (lock or lid (I. I'he majority ol sheep farmer" igree, 1 think, that it does not deleteriously oliect two-tooth ewes to hi put to "the ram. provided they are normally well grown and developed these men contend that tliev get a inucb better return from two-tooth ewes which are bred Iroin. than when they are kept dry, even where the lambing percentage is not big, and that, provided these young ewe> are done well while they are carrying the lamb, there is no check tc normal growth :in<l Envelopment. There are, however, quite a number il thought I ill, successful breeders who ?ontend that it is better practice to -arry the <"*w<\s over four-tooth lielore putting them to the rani. They claim that under this system there is no necessity to cull their sheep heavily as twotooths, loi, by keeping them empty. ,i much largei number can tie -alelv carried through tiie winter \\ her culling is then undertaken ot these n allien four-tooths it is found that fewer have to be rejected, for many late lambs that ill the previous year would have been <et aside on account of size or faulty development, have oeen ilile to outgrow these defects A Doubtful Advantage

I am inclined to doubt whether there is any pecuniary advantage to Im* gained from Weeding Iroin (vvo-iooth ewes m preference to carrying tlieni through dry, for there are main expenses and risks incurred in handling young breeding ewes, which, when totalled, apnea r to make the dry sheep the more profitable proposition. The position of the ewe, however, must be considered. At first glance it would appear obvious that it were better to carry the ewes through dry until four-tooth, thereby giving them every chance of developing fully and producing more and better lambs at their first lambing. There are, however, other factors to be studied beside the rapid development of the ewe to maturity. Under uncontrolled or natural conditions the ewe accepts service much earlier than under domesticated conditions. There appears to be tio set time or age, the first "heat period being dependent on the animal s development. Prior to sufficient physical development having been attained the female cannot conceive, even though mated during a "heat" period, because .a the ut acidity, which destroys the spermatozoa from the mak-. Nature therefore, apparently takes care that conception will not occur at an age when it will threaten the dam's surviv-i' r development Results of Delayed Breeding

When the time of this first mating is delayed for another year, the organs 01 the ewe cease to develop, the pilkie bones become harder, and less elastic, and the milk-secreting organs commence to atrophy from lack of use. The ewe also puts on an amount of surplus condition, which would ordinarily go to the nourishment or the foetus, and this interna! fat tends to restrict the space available to the.uterus. It is, therefore, usually the case that, although four-tooth maiden ewes are bigger and better conditioned than ewes of the same age which have been mated, they will produce only a small percentage of weedy lambs. A great many ewes which have been kept as maidens until they are fourtooth will also be found to be permanently barren. Provided in-lamb, twotooth ewes have plenty of winter keep, there is no reason why they should sutler m growth or development compared with dry ewes of the samt age. Condition and wool growth will certainly not be so good, but these an not nearly so important ultimately as e propensity to breed regularly. it is apparent from the lambing per centages which we normally get from our two-tooth ewes that while some ot them are put to the ram too early, tin majority are mated too late. It is mosi important, in view of their breeding ability in later life, to secure as many lambs as possible from these young sheep, and it would therefore be well worth trying a longer season with the rams. A Longer Mating Season Without incurring any considerable risk it should be a profitable practice in the North Island to put the rams with the two-tooths about the middle to the third week in February, leaving them in—if the rams were sure to be still active—for a fortnight after the older ewes were taken out. This would certainly mean a protracted two-tooth lambing, but the extra trouble incurred would be more than repaid in the future breeding performance of the ewe?.

What is r.iticed in the ewe in respect of lessened ability to produce inilk, owing to the arrest in development or atrophy of the milk-secreting glands when breeding is delayed bevond the normal time, is still more noticeable in dairy rattle. If a dairy farmer wishe3 his heifers to produce their maximum throughout their lives, he should never delay putting them with the bull at the normal time, on account of their being a little backward in size. With both cattle and sheep it is always possible to remedy under-size by liberal feeding, even during the period of gestation, but no after-treatment will correct the evils of delayed breeding.