Greatest Increase In Growth Research Articles

Effect of Addition of Inedible Tallow to a Calf Starter Fed to Holstein Calves

Summary Twenty-four male Holstein calves were fed limited whole milk to 35 days of age, a maximum of 4 lb. per day of calf starter containing 0.0, 2.5, 5.0, and 10.0% inedible stabilized tallow, and ad libitum alfalfa pellets to 92 days of age. The calves fed starters containing tallow consumed more calculated total digestible nutrients, which resulted in 5 to 6% greater increases in growth. The pounds of dry matter required per pound of live weight increase were less in the calves fed starters containing tallow, and total digestible nutrient utilization was not appreciably affected. Based on blood plasma values during the above feeding period and during a subsequent vitamin A depletion period, carotene and tocopherol utilization was unaffected by the inclusion of tallow in the starter. Digestibility and mineral balance studies with eight of the above calves and with four lambs indicated that when tallow was fed, there was a decrease in the apparent digestibility of dry matter, organic matter, crude protein, and nitrogen-free extract in the calves, whereas ether extract was increased for both species. Fecal calcium increased with the inclusion of tallow in the ration of calves. The results of this study indicate that inedible stabilized tallow could be used in calf starters.

The influence of thyroid hormone and androgen on comb growth in the White Leghron cockerel.

INTRODUCTION IT has been shown (Caridroit, 1941; Simmons, 1943; Blivaiss, 1947, and others) that comb growth is partly dependent upon the presence of thyroid hormone. Simmons reported that the growth of the comb in the White Leghorn capon could be increased by the administration of thyroxine and that the effect was roughly proportional to the dose. Blivaiss presented data showing a greater increase in growth of combs of Brown Leghorn capons and thyroidectomized males following the simultaneous administration of thyroxine and testosterone propionate than with either alone. Data submitted in the present paper substantiate some of the earlier work and support the suggestion of a synergistic action of thyroid hormone and androgen in the promotion of comb growth in the White Leghorn fowl. MATERIALS AND METHODS Changes in the weight of the comb, thyroids, and gonads, in response to various treatments designed to control the level of circulating thyroid hormone and androgen were studied. Animals were subjected t...