PASTURE FOR YOUNG DAIRY STOCK: II. EFFECT OF PREVIOUS NUTRITIONAL LEVEL AND AGE ON GROWTH OF HOLSTEIN HEIFER CALVES ON PASTURE

Abstract

Thirty-five Holstein heifer calves were assigned at birth to three ration schedules: moderate m; control c; high h. These three groups were weaned from whole milk during the 2nd, 7th and 9th weeks respectively with m and h calves receiving skim milk to 7 and 16 weeks of age respectively. m and c calves were allowed 4 pounds and h calves up to 6 pounds of meal daily with no limit on hay consumption. Moderate and high rationed calves were further sub-divided into three birth groups and were abruptly switched from the above feeding schedules and placed on pasture without supplementation at 56, 112, and 168 days. Treatment comparisons included live weight gain, withers height and heart girth measurements.High rationed calves made greater growth increases than m or c calves during the barn feeding period. These differences were greater for weight than for heart girth or withers increases. Pastured calves made smaller body gains during the first 28-day pasture period than barn-fed controls. This trend was reversed by the third pasture period with some pastured calves gaining over 2 pounds daily, h calves placed on pasture at 2 months of age made greater body weight gains and appeared to be thriftier than calves previously moderately rationed.