H—29

Of general interest in relation to the two systems of feeding management followed—controlled versus uncontrolled grazing—the performance of the herds on the two farms might be noted. The former averaged 347 lb. fat for the season and the latter 293 lb. fat, a difference of 54 lb. of fat in favour of controlled grazing. This difference probably over-measures the difference in per cow production slightly, since it tends to be influenced by the early rearing systems practised and, in any case, is a one-season figure. The herd average figures for the three seasons probably provide a better index, particularly if high-high animals (331 lb.) are compared with high-low (289 lb.) —a difference of 42 lb. per cow ; and when low-high (307 lb.) are compared with low-low (264 lb.) —a difference of 43 lb. These comparisons are between animals of similar rearing and involve three seasons' production for two-year, three-year, and mature cows. The agreement between the two estimates is surprisingly good. The observations made last year as to trends appearing might be restated in terms of the additional information available : (1) The advantage of good rearing over poor rearing when cattle are subsequently fed from first calving on a high even level of nutrition has not been great (plus 20 lb.) at the two-year-old stage, is more than maintained (plus 321b.) at the three-year stage, but has disappeared at the mature stage. (2) The advantage of good rearing as compared with poor rearing when cattle are subsequently fed unevenly from first lactation onwards has been quite substantial (plus 39 lb.) at the two-year stage, has disappeared at the threeyear stage (plus 1 lb.), and become a disadvantage at the mature stage (minus 10 lb.). (3) The advantage of good rearing combined with high even feeding during subsequent lactations over poor rearing combined with uneven lactational feeding has been substantial in two-year-olds (plus 54 lb.), three-year-olds (plus 67 lb.), and mature cows (plus 54 lb.) Farm-production Data.—The experiment has now reached a stage where it seems worth while summarizing the farm-production data from the two properties. The following table gives the mean production for all seasons for both normal and all cows and, in addition, shows the production per acre figure. All data refer to actual productions.

Farm-production Data (Butterfat)

„0n a normal cow basis the controlled farm has out-produced the uncontrolled by a mean of 42 lb. fat per cow and on a total cow basis by 62 lb. fat per cow. The difference is an expression of the fact that to date a higher number of abnormal lactations have been experienced on the uncontrolled farm. This, of course, may be an important consequence of this system of farming and will result, if continued, in a higher herdwastage figure under uncontrolled grazing as compared with controlled. The per acre productions are quoted for one year only (1948-49), since this is the first year that a reasonably normal age population herd has existed. The difference of 62 lb. of butterfat per acre is substantial.

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Per Cow Per Cow Per Acre (Normals, (All Cows, (1948-49 All Seasons). All Seasons). Season). lb. lb. lb. Controlled 319 315 251 Uncontrolled 277 253 189