Feeding and Management

Sheep get most of their feed from pastures and ranges that supply a variety of forage plants. It seldom pays to feed grain to breeding sheep or even to suckling lambs when they can have enough succulent herbage. On plenty of good forage, sheep can be kept thrifty and lambs can be raised to a market finish without grain. If grain is fed, about 100 pounds a year for a ewe and her lambs is the most that is likely to be profitable. Feeding sheep from stack, mow, and bin may be necessary during deep snows and extreme droughts, or when pastures and ranges are overstocked, or other conditions adversely affect grazing. Research in the use of grazing forage has been going on since 1923 at Dubois.

We have learned how important it is to detect range deterioration before it becomes far advanced. Studies with flocks on fenced pastures and with large bands on ranges in Idaho have yielded signs by which we can detect range depletion early enough to make corrections in management. The condition of the sheep may not accurately reflect the condition of the range. Deterioration of forage cover and soil may be noticeably progressing before the weights of ewes and lambs decline. Reseeding ranges, along with sagebrush eradication, is a way to increase forage twofold to tenfold on spring-fall ranges. As with stands of native forage species, correct grazing management of reseeded stands is imperative. These studies are providing valuable information on intensity of use and methods of grazing reseeded stands, as well as information on where, when, and how getting sufficient phosphorus from their feeds or grazing forages.

In various sheep-producing regions, the level of phosphorus in the blood of sheep has been noted as an important element in their nutrition. Lack of phosphorus is associated with unthriftiness in sheep and low profits from their production. The question arose concerning the availability of phosphorus in the forages of the western ranges, where about two-thirds of our sheep are produced. A project to investigate this problem was initiated in 1938 by the Idaho Agricultural Experiment Station and the Department. In 4 years, blood samples were collected from about 40 Columbia ewes that were kept by the Department at Dubois under intermountain conditions providing typical spring, summer, fall, and winter grazing. The ewes were wintered on alfalfa hay and fed some grain after lambing. Blood samples were taken from the jugular veins of the ewes at the close of the fall-range, winter-range, winter-feed-lot, lambing, spring-range, and summer-range periods. The samples were centrifuged and the plasma was analyzed at the University of Idaho.

We learned that seasonal trends in blood phosphorus level were fairly definite and that variations between seasons were significant. The highest levels were found on the winter and spring ranges; the lowest levels were at lambing time, in the late summer and fall, and in the winter feed lot. Supplemental feeding of cottonseed cake or oats on the winter range or feed lot increased the phosphorus in the blood. Ewes that had lambed had lower levels of blood phosphorus than those that had not yet lambed. Dry ewes had higher blood phosphorus than ewes that were pregnant or were suckling lambs. Ewes that were losing weight tended to have higher blood phosphorus than those that were maintaining their weights or were gaining. Blood phosphorus tended to decrease with the age of the ewes. No definite evidence of phosphorus deficiency was found, except the low blood-phosphorus levels that were associated with factors of season of the year, stage of pregnancy, the number of lambs the ewes were suckling, changes in weight, and advancing age.

The normal levels of blood phosphorus were found to be from 4 to 5 milligrams of inorganic phosphorus per 100 milliliters of blood plasma. The percentages of ewes having blood phosphorus values of 3.5 milligrams or below for the various seasons were 5.3 percent for the fall range, 2.5 percent for the feed lot, 20 percent at lambing, 2.7 percent for the spring range, and 10.0 percent for the summer range. The most critical time for supplying plenty of phosphorus in the diet of breeding ewes is at lambing time. Phosphorus can be fed free choice in a mixture of 2 parts of bone meal and 1 part of common salt by weight, when it appears they are not getting sufficient phosphorus from their feeds or grazing forages.

When feed is scarce and prices high, the producer must practice every economy in his methods of wintering sheep, particularly ewe lambs that are to be replacements in the breeding flocks.

In southern Utah many ewes are somewhat undersized at 18 months, the usual age for their first breeding. Feed is relatively scarce in that locality and lambs are sold as feeders or raised as breeding ewes. The usual practice there is to use the best ranges for ewes and lambs during the summer. After weaning, the ewe lambs go directly to the winter range. The following spring the best ranges are again used by ewes and lambs and the yearling ewes are placed on the less productive and drier ranges. In the following fall the yearling ewes go to the winter range as a part of the breeding bands. Although they are usually in thrifty condition at that time these yearling ewes are somewhat undersized.

The Utah Agricultural Experiment Station investigated the effects of feeding ewe lambs during the first winter of their lives, rather than keeping them on the winter range. In each of the 3 years of the experiment, 125 ewe lambs were obtained from a range operator. Seventy-five of them were fed in the feed lot and 50 were handled like other range sheep. The feeding periods each winter lasted about 6 months. The 75 lambs were fed at a level to insure satisfactory growth without fattening, and the other 50 ewe lambs were subjected to the variations and hazards of the ranges of southwestern Utah.

The lambs that got special feed their first winter made significantly greater gains in body weight (although most of the advantage was lost when the lambs were put on the range the following summer) and in weight of wool, unscoured and scoured, with fleeces of significantly longer staple. There were fewer deaths among them. Further, the percentage of ewes lambing at 2 years, of those alive at breeding age, was 64.7 in the groups that were fed and 45.5 in the range groups—in all, an increase of 42.6 percent more ewes lambing as a result of a little extra winter feed.