The costs of keeping an animal breeding stock is considerable and for economic animal production it is essential for each parent to rear a large number of progeny.
By way of example, the number of piglets produced per sow is one of the key economical performance indicators in pig farming. With normal weaning, at three to four weeks, the aim should be for about 18 to 24 pigs to be reared per sow per annum, such as for example by having two litters of 9 to 12 piglets each. However, in practice, averages fall below these optimal figures due to (1) time being lost between weaning one litter and conception of the next, (2) many litters being born with too few pigs, and (3) a percentage, such as for example about 12%, of pigs being either stillborn or dying within the first few weeks of life. All of these result in a lower than optimal number of piglets surviving. The lower the number of piglets which survive and mature into pigs for meat production or breeding, the greater the cost to the farmer and the higher is the cost on a per pig basis of maintaining the herd, all of which contribute to a reduction in income for the farmer and a lowering of profits for the enterprise managing the pigs or similar.
Therefore, there is a need for management of the pig herd that allows a greater number of piglets to be born alive and survive to maturity than hitherto before was considered normal, as well as a need for piglets to develop faster and grow more quickly, and perhaps to have litters at a younger age and to have more piglets in a litter.
Betaine has been used in the past as a feed supplement for animals, but until recently, knowledge with regard to its role in animal metabolism has been sparse.
Betaine has recently been reported to both improve gut function and to increase the food intake and growth of animals. Betaine has also been found to decrease the body fat of for example fish, chicks, piglets and growing pigs [see e.g. Virtanen, E. et al., Effects of food containing betaine/amino acid additive on the osmotic adaption of young Atlantic salmon, Salmo salar L. Aquaculture 83 (1989) 109-122; Saunderson, C. L. and MacKinlay, J., Changes in body weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks, British J. Nutrition 63 (1990)339-349; and Virtanen, E. and Campbell, R., Reduzierung der Ruckenspeckdicke durch Einsatz von Betain bei Mastschweinen (Reduction of backfat thickness through betaine supplementation of diets for fattening pigs). Handbuch der tierischer Veredlung. Verlag H. Kamlage, Osnabruck, Deutschland, 19 (1994) 145-150]. Betaine has also been reported to have pharmacological effects. Thus, for example proline betaine has been reported to prevent perosis in chicks and glycine betaine has been reported to prevent the detrimental effects of coccidiosis in broilers (PCT/FI94/00166).
Until now, no investigations have been conducted to determine the effect of betaine on the reproduction of animals. It has now been surprisingly discovered that betaine, particularly when used in appropriate, predetermined amounts in feed stock, has resulted in significantly higher numbers of piglets in a litter being born alive. Even though betaine may have been used in the past in connection with pigs, the inventors have surprisingly discovered a hitherto before unknown property of the betaine. This property which has been newly discovered by the inventors relates to using betaine to achieve more fertile and fecund sows with the result that sows now have larger litters, particularly if the sows are fed betaine during lactation. As already stated, pigs are mentioned here by way of example, the invention being applicable to a large number of animals.