GOOD LITTERS

Waikato Times, Volume 122, Issue 20494, 10 May 1938, Page 18 (Supplement)

GOOD LITTERS

Advice To Producers Caring For The Sow Many farmers wonder why at one time a sow produces a good litter and at another time a poor litter. Usually when his sow produces a large, even litter, he takes a reasonable pride in the event, but wonders why it happened to be so good. Mr M. J. Scott, 8.A., B.Sc., Director of the Pig Industry, in the following article gives some of the reasons for good litter production:— “A good litter should weigh between 8001 b. and 4001 b. at eight weeks old, the greater the number of piglets the better. Thus 10 piglets at 301 b. each is a better litter than six piglets of 501 b. each. A spring balance is a valuable adjunct in assessing litter value. The production of good litters begins with the shedding of the eggs from the ovaries of the sow during the heat period. It is usually considered that 20 to 30 ova are shed over a period of 30 to 36 hours from the first onset of heat by a sow that is in good condition for breeding. The actual onset of heat and the number of eggs produced during the oestrum are determined in the sow, as in every other animal, by the amount of improvement that is taking place in the animal at that time. This improvement is commonly spoken of as “flushing.” In the sow this flushing automatically takes place immediately after weaning, and is due to the reabsorption of milk from the udder back into the sow’s body. It is probably because of this automatic flushing that oestrum occurs so regularly within three to six days of weaning. It is also probably true that where the first heat period is missed and difficulty is subsequently experienced in getting a sow in pig this difficulty is because of the absence of flushing. CARE AT WEANING “Many owners, at weaning, turn the sow out on a bare paddock and reduce her feed supply, and even let her back to the litter once a day so as to dry her off. If the sow is in high condition this may be all right, but if the sow is in a low condition this treatment may result in delayed oestrum or the shedding of few eggs, and a small litter following. Where sows fail to come on heat after weaning, they should be shut up and fed heavily for a week before tlfe next heat period is due. On the other hand, where maiden sows are in such high condition that they are incapable of rapid improvement at the onset of oestrum, small litters often result, and this can be prevented by keeping the sow always in good condition, but somewhere below the peak of her form. POINTS TO REMEMBER “It was mentioned above that 20 to 30 ova may be shed over a period of 30 to 36 hours from the time the sow first comes on heat. These eggs are shed one at a time, then if service takes place when only a few eggs are shed only a few will be fertilised and a small litter will result. The sperm of the male remains active on the uterus for about eight to ten hours, so that if service takes place at 24 hours after heat begins all eggs shed up to 32 to 34 hours may be fertilised. If these points are appreciated the sow will be served ideally, that is, with every prospefct of a big litter, about 24 to 36 hours after she comes on heat. “In practice the best thing is probably to give one service when the sow is well on heat, and a second one as late as the sow will stand service.”