SELECTION OF BULLS

Hawera Star, Volume LII, 19 November 1932, Page 7

SELECTION OF BULLS

DETERMINING THE VALUE HINTS FOR PURCHASERS VALUE OF MILKING .RECORDS. Air W. Lawson. Director of Ag iculture for \Yest Sussex, declares tint many dairy bulls are selected on appearance. It is essential, it type, strength and constitution are to be obtained, that conformation i:e given due consideration, but selection cm appearance alone is not enough. Attention must be given fo pedigree and the production records of related l animals, and although these arc of considerable assistance in the .selection of dairy bulls, there are pitfalls which cannot be avoided until breeding ju.blems and the influence of heredity ;ae better understood. The best indication of me value of a bull for use in a dairy herd :s the relationship which exists between the production of his daughters and that ol their dams. McCandlisli and Kay have made a study of some Ayrshire herd sires in the south of Scotland. The district is notable as tbe hist ini the British Isles to adopt systematic milk recording methods. Considerable, improvement has been effected. j SIX DAUGHTERS TESTED. j The work was commenced in 1003, and has been continuous ever since. , The recorded cows are classified in to I three groups, and whereas in 1914 the classification into Ist, 2nd and 3rd class showed the recorded cows to be, divided unto 331, 063 and 10 per cent j respectively; in 1922 the figures were' 59-J-, 37-A and 3 per cent. It is not' argued that this improvement s clue to selection; improved methods of feeding and management must be given due weight. In the study of sires it was decided to include only bulls where the record of six of his (laughters and the records of the dams of those daughters were available. Davidson also favoured six tested daughters as the minimum on which to judge a •bull. but some American investigators have adopted five daughters as a minimum on which to judge a- bull. There were ultimately available 79 bulls, 60 of whom had only between 6 and 10 daughters per hull and six had over 20 daughters each. The records had to be corrected for age and other factors in accordance with information previously obtained by the investigators. The dams used had an average production corrected to maturity of 76491 b of milk, while the daughters nft'eraged 71801 b of milk, a decrease of about 6 per cent. On the whole, therefore, these selected bulls did not improve production.

VARIATION OF PRODUCTION. The variation in production between dams and daughters ranges from a decrease of 2/ per cent to au increase or 14 per cent in milk yield. Fiftytiiree bulls reduced the average 11111 k yield and 26 bulls increased tlie milk yield. If a more general classification was made two bulls were very ing increases ot between 11 and 16 per cent, 11 were good, with increases of between 6 and 10 per cent, 40 were indifferent where the increase or decrease was within 5 per cent, 12 were bad, giving decreases of from 0 to 10 per cent, and 14 were very bad rv ith decreases of over 10 per cent. Thus selection can materially affect production. At present it would appear that the only certain method of selecting a sire is by the progeny test. In judging the merits of the dams and daughters it is necessary l to correct the yields so as to allow for other factors which influence yield. The influence of age at first calving on production is a factor on which little definite information is available, and on which practical men have differences of opinion. Fellies, working in America with Jerseys and Friesians, found that with Jerseys the maximum production was when heifers produced their first calf at from 28 to 32 months old. With Friesians the better jeod n'cers were between 24 and 30 months.

PROVED SIRES ESSENTIAL. The actual settlement of whether or not an animal is a really worthy sire should not be decided until at least six daughters have been proved under conditions which allow of corrections for conditions discussed above. We will no doubt find. says Mr Lawson, that very many bulls actually do harm to milk yields and until wo can increase the number of the better breeding bulls and preserve them as long as possible in a fertile condition tin* average milk due to hereditary characters will be difficult to increase. Meantime records should be regarded as essential knowledge before purchasing a hull. If a hull is used in the second year of bis life lie will be practically six years old before the necessary inf-or-| mat inn is obtained by the progeny] test. In a small herd the. cost of ( keeping the bulls would be prohibitive i and some system" of exchange would] appear to be necessary. j