Fluorine in Phosphates for Fattening Lambs

Fluorine may be toxic when present in considerable quantities in the rations of animals. J. D. Hatfield, C. L. Shrewsbury, and L. P. Doyle, of Purdue University, fed western fattening lambs rock phosphate containing 3.85 percent fluorine as a mineral supplement, in amounts furnishing 1.5, 3.0, and 6.0 milligrams of fluorine per kilogram of body weight a day. The investigators found that the consumption of grain declined and growth was depressed in the lot receiving 6.0 milligrams. As the fluorine intake was increased, the breaking strength per gram of bone went down proportionately, and the percentages of ash and fluorine in the bone increased. The weight of the thyroid gland declined as the amount of fluorine went up.

The Department also made laboratory studies of the problem. The manufacture of defluorinated phosphates on a large scale began in the midst of the war, and the Department undertook feed-lot tests on fattening lambs at Beltsville in an effort to aid manufacturers in standardizing their products. Earlier tests had shown that the temperature of defluorination was important in determining the availability of phosphorus in the product to the animal. In the feeding tests three commercial defluorinated phosphates were found to be nearly as good as bonemeal in availability. The chief measure of phosphorus availability of a product was the level of inorganic phosphorus in the blood serum, although gain in weight, bone composition, and carcass quality were also considered as indices.

Phenothiazine is one of the most important discoveries ever made for keeping sheep healthy. Parasites and parasitic diseases have troubled sheep seriously from time immemorial. Copper sulfate and nicotine sulfate have been used to control several of the internal parasites, but since phenothiazine became available, soon after its discovery was announced in 1938, it has been more widely used for that purpose than any other drug. Workers in the Bureau of Animal Industry have found that sheep will consume sufficient quantities of a suitable mixture of phenothiazine and salt to result in reasonably effective control of stomach worms and intestinal roundworms. A satisfactory mixture consists of one part, by weight, of powdered phenothiazine and nine parts of loose granular salt. This method of administering the drug saves labor and expense.

Breeding Hampshire Ewe Lambs

Sheepmen generally breed their ewes for the first time when the ewes are about 18 months old, so they will lamb at 2 years of age. Because many ewes born early in the spring come in heat in the fall, it has been reasoned that lifetime production may be increased by breeding them then. Hampshires, which develop early, seemed well suited for a test of the idea.

The Department and the South Dakota Agricultural Experiment Station collected data on 119 pairs of Hampshire ewes born at the Belle Fourche Field Station at Newell, S. Dak. The lambs were paired on the basis of age, weight, and family relationship. One of each pair was mated as a lamb at the age of 9 or 10 months, and the other was bred at the age of 18 or 19 months. Eighty-four conceived, and were designated as group A. The 35 that failed to conceive as lambs were put in group B. Their pair mates were classified as groups C and D, respectively. Performance was followed for 5 years. Group A lambs were lighter in weight at 2 years, but they made it up by the third year. Group A produced 89 lambs at 14 to 16 months of age. The total numbers of lambs born in groups A, B, C, and D were 427, 135, 370, and 140, respectively, and the' totals raised to weaning age were 305, 92, 255, and 102. Average weaning weights of lambs in the four groups were 67.0, 68.2, 70.1, and 69.0 pounds, respectively. The average weaning weight of lambs from group A in the first year was 54.3 pounds, the lightest of any group of lambs. Group A produced a total of 2,572 pounds more lambs at weaning time than group C. The average annual fleece weights of the ewes in these groups were 7.9, 8.3, 8.2, and 8.0 pounds, respectively.

Breeding these Hampshire ewes for the first time as lambs resulted in a material increase in total lamb production, with only a very slight decrease in wool production. Early breeding appears to be economical and profitable under conditions where ewe lambs can develop adequately and where Hampshire or similar breeds can be given extra feed and care at reasonable cost.

State experiment stations and the Department have under way many other research projects that will help solve new problems of great importance to producers of lamb meat, wool, and the fur of sheep and lambs. Specifically, emphasis is placed on investigations having to do with improving the manufacturing properties of wool, in preparation for the competition between natural and synthetic fibers, and on greater efficiency in the production of lamb meat and wool in all regions that raise sheep commercially and among all important breeds. Research men hope for the same kind of progress in these studies that has been made in producing more wool. The average annual fleece weight of wool in the United States is now about 8 pounds. A century ago it was only 2 pounds.

THE AUTHOR

Damon A. Spencer, as senior animal husbandman in the Bureau of Animal Industry, has been in charge of the Bureau's sheep, goat, and animal-fiber investigations since 1920. These investigations have included 40 research projects, involving the use of about 10,000 sheep and lambs, about 100 goats and kids, and about 50,000 pounds of wool each year. This research program has included cooperation with nine Federal bureaus and 42 State experiment stations, in finding scientific solutions for practical problems in the sheep, goat, and animal-fiber industries.