H —2s

A satisfactory basis of comparison with which to assess the standard of performance of the A.I. daughters is extremely difficult to obtain. That used is one o£,the best available and consists of comparing the production of the A.I. heifers in each herd, corrected to a maturity basis with the production of the mature cows in the herd. It is a method which bears heavily against the A.l. daughters, as the mature-cow figures are derived from a highly selected sample. On this basis the A.I. two-year-olds represent & gain of 30 lb. of butterfat per cow in producing ability. This figure is almost the same as that shown by the first crop in the 1946-47 season, where the difference between the production of A.I. two-year-olds and mature cows in the same herds averaged 33 lb. of butterfat in favour of the A.I. cattle. The three-year-old performances were disappointing, showing an advantage over mature cows of only 5 lb. of fat in producing ability. This drop relative" to their two-year-old performance is probably associated with the poorer dairy season of 1947-48. The cattle concerned actually produced less than they had done as two-year-olds. ' The second year's crop of two-year-olds averaged 47 lb. less than the first crop in 1946-47. The performances of the different bulls in relation to their survey results are summarized below :

Merit Sires

In every case the A.I. cattle yielded less than might be expected from the bulls' surveys. This might be explained on a basis of a generally poorer standard of efficiency of feeding and management in the commercial herds in whieh the A.I. daughters were placed, together with a poorer standard of dams. Investigations are proceeding to test the validity of these suggestions, but it seems abundantly clear that the use of a merit bull of a 4001b. daughter standard will not automatically result in cattle of a 400 lb standard unless feeding and management are at a very high level.

71

Official Survey. A. I. Daughters. Number of Laets. Fat. Number of Laets. Fat. ' lb. lb. Greencrofts Hopes Prince— Dams 41 346 12 16 348 Final daughters 41 374 12 16 389 All daughters 52 373 40 73 349 Kuku Butter-King— Dams 13 367 19 30 340 Final daughters 13 373 19 30 341 All daughters 49 81 342 Awatea Phill— Dams 14 388 9 12 324 Private final daughters 14 387 9 12 351 All daughters 16 384 27 50 330 Erinview Teddy— Dams 10 18 367 14 14 309 Final daughters 10 18 455 14 14 337 All daughters 18 38 451 25 25 347 Lockhart Golden Laddie— Dams 20 30 340 8 8 307 Final daughters 20 30 389 8 8 318 All daughters 49 88 377 27 27 325 Greencroft Anticipation— Dams .. 14 19 349 4 4 432 Final daughters 14 19 368 4 4 382 ■ All daughters 26 59 358 12 12 342 McLucky— Dams 17 378 6 6 301 Intermediate daughters 17 388 6 6 327 All daughters 16 16 323