Control of Hermaphrodism

Hermaphrodism or intersexuality occurs more frequently in milk goats than in any other farm animal. It is usually possible to recognize hermaphrodite kids at birth, but sometimes positive indications are not evident for several months. A colleague, O. N. Eaton, found in anatomical examinations that not only their external genitalia but also the internal structures resemble those of both sexes. Since hermaphrodites will not breed, failure to recognize the external manifestations of this character results in disappointment and economic loss to breeders. Dr. Eaton and I, in several years of observation of the Department's herd, calculated that 11.1 percent of the kids produced in the Saanen breed and 6 percent in the Toggenburg breed were intersexual.

Horned hermaphrodites are rare. In purebred herds where attention is given to the breeding of polled animals, the possible existence of a relation between the polled condition and the birth of hermaphrodites has economic significance. Eaton's analysis of breeding data confirms the inheritance of intersexuality as a simple recessive and of hornlessness as a simple dominant. Close agreement was found between the observed number of horned and hermaphrodite animals and those expected if there is linkage between the genes for the hornless and hermaphroditic characters. If this genetic theory is correct, it suggests that breeders have been increasing the gene frequency for hermaphrodism. More important, it indicates that the elimination of hermaphrodism from goat herds should be fairly easy by the use of one horned parent in each mating. The rare occurrence of horned intersexes is believed to be due to the crossing over between the closely linked genes for hornlessness and hermophrodism.

Feeding Milk Goats

Individual goats differ in their ability to turn feed into milk or growth. The variations may be due largely to individual differences in appetite and inherited ability to utilize feed. In the Department's herd, milking does are fed at the rate of one pound of grain for each 4 pounds of milk produced. Thus, a doe that increases milk production with increased grain fed is permitted to demonstrate her maximum ability.

Because feeds vary considerably in composition, the nutritional requirements of animals can be more accurately expressed in terms of digestible nutrients than by pounds of feed in the ration. W. L. Gaines of the University of Illinois reports the development of a standard equation for calculating the feed requirements of milking goats. The equation is given as DN=0.016W / 0.3 FCM, in which DN equals the daily digestible nutrients intake in pounds, W equals the live weight of the doe in pounds, and FCM equals the daily milk energy yield in pounds of 4-percent milk. The milk production of a doe may be corrected to a butterfat basis of 4 percent by use of the Gaines-Davidson formula: FCM (fat corrected milk) = OAM + 15F, in which M represents the weight of milk and F the weight of fat. By converting milk yields to a FCM basis more accurate comparisons of the productive abilities of individual does is possible.

To provide succulent feeds for milking does in winter, technicians at the New Jersey Agricultural Experiment Station stored green lawn clippings by thoroughly packing them in tight barrels with molasses as a preservative. With 100 pounds of molasses to 1 ton of clippings, they prepared a silage on which does thrived.

We also know more about the need for proper mineral balance in rations for goats. Besides common salt, the minerals most likely to be deficient in feeds are calcium and phosphorus. The cereal grains and high-protein byproducts, such as wheat bran, linseed, soybean, and cottonseed meals, are relatively rich in phosphorus. Feeding cereal grains and protein concentrates with legumes of alfalfa, clover, lespedeza, or soybean hay that furnish calcium gives a ration that provides enough calcium and phosphorus. If necessary, mixtures of limestone or bone-meal one part, and salt, two parts, may be given to goats free choice. There have been no developments to indicate that vitamins other than A and D are needed in goat feeding.

About Goat's Milk

Investigators recently have confirmed and added to many of the findings of J. A. Gamble, N. R. Ellis, and A. K. Besley. These Department workers found in 1939 that the milk of Saanen and Toggenburg goats resembles Holstein cow's milk in percentage of water, lactose, fat, protein, and ash, although subject to greater variation with the advance of lactation than milk of either Holstein or Jersey. The percentage of total solids in goat's milk ranged from 13.05 in February to 10.78 in August.

Goat's milk shows a soft curd, small fat globules, and a rather high buffer index. It contains a high ratio of albumin and globulin to casein and greater quantities of the fatty acids, caproic, caprylic, and capric, than cow's milk. Milk of both goats and cows is low in iron and copper, and in feeding tests nutritional anemia developed on the unsupplemented milk diets. The calcium and phosphorus content of the milks appeared satisfactory. In feeding trials with rats and guinea pigs, Gamble, Ellis, and Besley found goat's milk similar to Holstein milk in vitamin A and D values, relatively high in vitamin B, (thiamine), and lacking in vitamin E. They also noted that spring and summer milk had more ascorbic acid (vitamin C) than did fall and winter milk, and that the exposure of milk to air and light materially reduced the ascorbic acid content. Both goat and cow milks were inadequate sources of ascorbic acid.

Because pasteurization of goat's milk distributed for human consumption is now required by public-health authorities in many localities, its effects on nutritive values are important. According to Ellis and others, the solubility of calcium and phosphorus is slightly increased and the curd tension is reduced by pasteurization. This process improves the keeping quality more than the flavor of fresh goat's milk. Pasteurization by holding the milk at not less than 142° F. for 30 minutes caused a decrease of from 33 to 45 percent in the content of reduced ascorbic acid. The phosphatase test, for the detection of improper pasteurization, is not applicable to goat's milk, as this enzyme is inactivated sufficiently to pass the test when the milk is heated only 5 minutes at 143° F.