by America's Sheep Trails
From: America’s Sheep Trails
One of the most unusual experiments in sheep breeding came toward the close of the nineteenth century. In the summer of 1886, Alexander Graham Bell, inventor of the telephone, spent his vacation on Cape Breton Island in Nova Scotia. The fact that his neighbors operated on one lamb per birth turned Bell’s interest to increased prolificacy. But greater prolificacy suggested added trouble, for ewes had only a single pair of teats. Bell felt that more nipples and greater milk production were essential to support increased lambs. Among different kinds of animals, Bell knew that those with the larger number of mammae had more offspring at a birth, and felt that this phenomenon presented a tangible point for selection.
In 1889, therefore, Dr. Bell announced that he would pay a premium for ewes that had more than two functional teats. Little is known about the genetic background of Nova Scotia sheep, but most of them possess a tendency toward multiple nipples and the trait appeared in their offspring quite regularly. At the end of the first year, Bell’s breeding ewes averaged 2.5 nipples; by 1900, 4.28; and by 1910, 6.1. In Mrs. Bell’s flock, carried on after the inventor’s flock was divided, the average was 5.51 in 1923. It is interesting that the added nipples did not stimulate additional mammary glands, but there was a definite forward extension of the mammary tissue from the gland already existing. Milk capacity of these forward nipples seemed small.
While the flock was started with two rams carrying the normal mammary pattern, four-nipple rams were in use by 1895, and six-nippled rams by 1899. In 1910 the rams averaged 6.8 nipples but after 1913 only six-nipples were used. Six-nippled sheep are very rare, only two having been reported in twenty-two years that were not connected with Dr. Bell’s Beinn Breagh flock. The foregoing selection figures illustrate the selection applied to the breeding stock- in the lambs the number of nipples increased from 2.27 in the crop of 1890 to 5.23 inn the crop of 1923. However, some years showed higher averages-5.40 in 1913; 5.38 in 1914; and 5.39 in 1921.
At the start of his experiments, Dr. Bell reported that his normal-nipples showed 24 percent of twin births, while his multi-nippled ewes produced 42 percent. His selection system, based on this observation, bore fruit, for the percentage of ewes showing multiple births increased markedly during the period. At the time of Dr. Bell’s death in 1922, the ewe flock showed multiple births in more than half the parturitions.
When Mrs. Bell died a year later, a flock of thirteen ewes and one ram was turned over to the University of New Hampshire Experimental Station at Durham, under charge of Dr. E.G. Ritzman. For the five years, 1923-33, the total lamb weights per ewe, at eight weeks of age were 63.7 pounds for 70 ewes bearing twins, and 36.4 pounds for 231 ewes having single births. The twin-producing ewes had 75 percent more weight to their credit.
For several years previous to receiving the multi-nipples flock, Ritzman had been crossbreeding Rambouillets and Southdowns, to produce a type that give more satisfactory yields of mutton and wool combined. When the Beinn Breagh flock arrived at the station, this type of crossbred sheep was mate to it, since bell had paid little or no attention to mutton and fleece quality. The high twinning capacity was retained and improved, nearly 70 percent of the ewes showing multiple births in 1938, and nearly 80 percent a year later. To give a uniform breed appearance, a four-nippled Suffolk ram was crossed in. In a940 the breed was turned over to the Bureau of Animal Industry in Beltsville, Maryland, to be established genetically, and in the fall of 1941 it was established at the Morgan Horse Farm in Middlebury, Vermont.
Statistical studies after four years of work at the new location indicates that part of the increased fertility was due to added age in the ewes, since the proportion of twins normally is greatest between four and ten years in Merino ewes, and up to four to seven years in mutton breeds. Only in four-nippled ewes was there a significant relationship between number of lambs and number of nipples. Thus far, these sheep have assumed no commercial importance, but the method by which they were developed, and the type of records kept, make it an interesting example of breed synthesis
The following appeared in the December 1932 issue of The Sheep breeder, on page 31.
Two distinguished rams have been sent by the University of New Hampshire to the Rothamsted Experimental station in England, where they will be used in sheep breeding work. The Rothamsted research will be similiar to that already begun by Professor E. G. Ritzman, director of Animal Husbandry Research , to develop sheep which will produce young inpairs and carry four or more nipples yeilding sufficient milk to feed their twins. Mr. Ritzman is also striving for a combination of fine wool, rapid maturity and high mutton production along with the multi-nippled, high fecundity characteristies.