H—29

Cow Stage : The two farms in this experiment are reaching the pasture condition characteristic of the two systems of management. The " controlled-grazing farm " shows considerable improvement on the peat areas and the general quality of the sward over the whole is now reasonably good. The poor soil type involved, however, imposes some restriction here, and it is unlikely that the area will ever be capable of being described as really first-class pasture land. The " uncontrolled-grazing farm " now shows plainly the effect of alternating complete and incomplete utilization. Summer growth during the dry period was good because of the protection afforded by long unused herbage from the good growth of the spring. Weather during the season was good in winter and spring. The summer was relatively dry. Feeding out on the controlled farm began in early January and continued at a high level until the end of March. Autumn growth was only moderate. The uncontrolled area carried a fair amount of feed right through as a result of good spring growth. Pastures did not become bare and close grazed until mid-winter. Production Results : These are very difficult to summarize and interpret at present. The cattle are still young and age distribution is abnormal. Results indicate trends only. Little weight can be given to actual differences. For the first time identical twins contribute to the data, 3 " well-grown " and 4 " poorly-grown " sets being split at two years to yield comparisons with identical animals between the treatments highhigh and high-low and the treatments low-high and low-low. Because for all other comparisons their value is equivalent to that of non-twins, the group averages for each treatment include all cattle irrespective of whether they are twins or not. Treated in this way the twin pairs become " pilot groups " extracted from the whole data. Current season's data will provide four main group comparisons with identical twin material. The mean fat yield figures for the four groups are summarized below:—

Mean Fat Yields (Seasonal Basis)*

Mean productions of the twin pairs on a group basis were as follows :

Mean Fat Yields (Seasonal Basis)

77

Type of Nutrition. 1947-48 Season. All Seasons. Pre-calving. Post-calving. Two Years. Three Years. Two Years. Three Years. Well grown Poorly grown .. Well grown Poorly grown .. High even (HH) High even (LH) Uneven (HL) Uneven (LL) .. lb. 300 (10) 281 (11) 286 (12) 225 (12) lb. 330 (10) 311 (10) 273 (8) 292 (6) lb. 297 (22) 283 (23) 284 (22) 238 (22) lb. 330 (10) 311 (10) 273 (8) 292 (6) * From calving to 31st May.

Type of Nutrition. Pat Yield, Pre-calving. Post-calving. Seasonal Basis. Well grown .. .. < Poorly grown .. .. < High even (HH) Uneven (HL) High even (LH) Uneven (LL) .. lb. 310 (3) 262 (3) 270 (4) 195 (4)