BREEDING POINTS

Press, Volume LXX, Issue 21255, 29 August 1934, Page 7

BREEDING POINTS

DISCUSSION OF PROBLEMS IMPORTANCE OF CORRECT FEEDING Problems of efficient breeding formed the subject of an interesting address by Mr Allan Leslie, veterinarian of Canterbury Agricultural College, Lincoln in a recent lecture to a meeting of Southland farmers. He emphasised the importance of sound principles in the breeding in horses, cattle, sheep, and pigs, arid explained some of the practical aspects. He said that in New Zealand it was known that only. 60 per cent, of the mares bred. The reasons for sterility, temporary or permanent, and diminished fertility, were many. Lack of fertility was due to hereditary and environmental influences. The latter included feeding, management, and disease. He considered that not sufficient attention was paid to factors, other than bacteria, affecting the fertility of stock. Very important influences were the physical maturity of stock at the time of mating, the state of development at first breeding, feeding in early life, winter feeding during the dry period, and selection for regular breeding. Importance of Sires The ability to produce living offspring was an inherited quality. Stallions, bulls, boars, or rams could be good, bad, or indifferent stock producers. There was now an accumulation of evidence that the sire played an important part in sterility. Twinning in ewes could be brought into a flock by using rams that were twins. In a few generations the fertility of a flock could readily be increased if desired. There was a common belief and practice that lambing percentages could be affected by using a ram. one of twins, on ewes which usuallv had singles. That was incorrect. '.However, it was true that the progeny from, such mating would have the "heriditary influences which made for twinning. The fact was that the ewe decided the number of offspring. Close Breeding: of Figs :■ Th* flaim that close breeding of ipigs led to infertility and smaller hti lers was not based on fact. The lack I of fertility was not due to the close ' breeding, but. to the use of boars and sows in which undesirable hereditary traits were apparent. Those traits resulted in the death of embryos during early development. If a boar free from the taint was used the litter size would be increased immediately. In outcrossing or cross breeding the result would be the same. As in all stock the secret of success was in close breeding provided there was also efficient culling of undesirables in the early stages of establishment. Kmphasising the importance of considering the state of physical maturity in maiden stock, Mr Leslie said that -uch was more important than age. Far too often in New Zealand undersired, or poorly nourished stockheifers and hoggets especially—were bred from. There was no doubt that the practice impaired the breeding 'efficiency of that stock later in life '•and shortened their economic lives. It I was common for immature two-tooths, which were fed extensively on roots j or an unbalanced diet before lambing, i to slip their lambs.

Claim for Good Supplementary Food To-day there was an increasing claim for the feeding of better supplementary food in the form of oat sheaf chaff or hay. In addition a mineral mixture was required, including lime, super and salt, or bone meal and salt. There were slight disorders often following births which lead to temporary .sterility and mares and cows so affected might be found to have recovered after missing one season. High

milk production had an effect on fertility, and it was for that reason that it was good policy for horse breeders to mate wet mares at the first and second heat period. The length of the oestral period had a direct effect on fertility, as it was now known that male and female fertilising cells did not live indefinitely. It had been found that belter fertility followed the mating of animals towards the end of the oestral period. This was of importance to horse breeders especially, as the period often extended over four to six days. A second service for mares was recommended where the heat period was prolonged. Sows mated on the second day of "their period gave larger litters, while it was best to mate high milk producing cows when they were actually going off the period. Syringing cows and mares definitely affected fertilising vitality. Effect of Feeding Correct feeuing was as important as any other factor. If there were seasonal fluctuations in the nutritional conditions breeding stock lost efficiency. Poorly fed cows often failed to breed in the spring because of the sudden change of diet causing an unbalance of the glands and therefore infertility. Feeding of supplementary fodder in the spring often cleared up temporary sterility. In contagious abortion in cattle Mr Leslie said that the result was frequently temporary and permanent sterility. Fully 30 per cent, of the cows in New Zealand were affected. The disease was usually introduced into herds by brought-in-cows or bv carrier bulls. He urged the use of blood tests, which were important in detecting the trouble. There were facilities for that testing, and farmers should settle all doubts immediately they 'were formed. Another important consideration was that sires could be infertile at the beginning of the season, perhaps due to poor condition or- excessive fatness. Sires should be well fed on a highly nitrogenous diet and given adequate exercise. Regularity in breeding favoured better ferI tility.

Stock Reform in Russia Mr Leslie referred to rapid stock improvements in Russia, where artificial insemination methods were adopted. In that way the most was madeoofi f proved stock, and he thought that in New Zealand there was a great opportunity to improve stock by using

that method. Indiscriminate importations of stock were bad, and led to haphazard breeding. Pedigree meant no more than the family history, and was valueless if not coupled with production or performance. He recommended in-breeding and line breeding as methods of stock improvement not sufficiently practised. The haphazard breeding so common in New Zealand led to great lack of uniformity. Control over heredity led to control over variation. Close breeding did not result in lack of constitution if selection was made properly. The aim of all breeders should be to breed stock suited to local conditions. He did not recommend the use of first crosses for breeding unless for the establishment of a new strain.