Experiment Station Record, Volume 92, January-June, 1945 Page: 34
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34 EXPERIMENT STATION RECORD [Vol. 92
performance should be the basis for retention rather than length of pedigree, which
lacks genetic significance. The average interval between generations (11-12 yr.)
constitutes a real limitation to selective breeding in these light horses. In Thoroughbreds,
the most prolific sires of stake winners produced more than three times as
many stake winners as the poors, whereas the most prolific grandsires produced
only about one and one-half times as many stake winners as poors, thus showing how
quickly the influence of an ancestor decreases in succeeding generations.
Some aspects of fertility in horses raised under western range conditions,
S. R. SPEELMAN, W. M. DAWSON, and R. W. PHILUPS. (U. S. D. A. and Mont.
Expt. Sta.). (Jour. Anim. Sci., 3 (1944), No. 3, pp. 233-241, illus. 1).-Certain
aspects of fertility of 209 mares bred to 14 stallions and producing 568 foals at
the U. S. Range Livestock Experiment Station over a 15-yr. period are presented.
Fertility results from different matings of the mares did not seem to be related to
years but rather to the fertility of the stallion with which they were mated during
the different years. Very young or aged mares had a lower fertility than those of
intermediate age. Among the 44 Belgian mares bred, 70.5 percent foaled; 328
grade draft mares, 50 percent; 180 Morgan mares, 72.2 percent; and among 401
grade light mares bred, 60.6 percent foaled. Of the foals born 87.2 percent were
A comparative study of two biologic and two chemical techniques of pregnancy
diagnosis in the mare, D. T. MAYER. (Mo. Expt. Sta.). (Amer. Jour.
Vet. Res., 5 (1944), No. 16, pp. 209-214).--After the third month of gestation,
biological tests of the urine for gonadotrophin and two chemical tests of the urine
gave positive results for pregnancy on all of 66 mares producing foals at the U. S.
D. A. Range Livestock Experiment Station, Miles City, Mont.; U. S. Morgan
Horse Farm, Middlebury, Vt.; and U. S. D. A. Animal Disease Research Center,
Beltsville, Md. However, in only 96.4 percent of the mares not foaling were the
two chemical methods correct, and the biological test was only 85.7 percent accurate
on these mares. The blood-serum test was the least accurate of any of the four
employed, yielding but 82 percent correct diagnoses in both pregnant and nonpregnant
Hereditary congenital lethal spasms in Jersey cattle, P. W. GREGORY, S. W.
MEAD, and W. M. REGAN. (Univ. Calif.). (Jour. Hered., 35 (1944), No. 7, pp.
195-200, illus. 1).-A new type of hereditary spasm in Jersey cattle was found to
occur in several herds using bulls related to a single herd of high-producing purebred
Jerseys. The spasmodic condition was inherited as a recessive autosomal
lethal. Affected animals died within a few weeks. Four of five sires in two herds
progeny tested for the defect proved to be heterozygous. The gene was evidently
present in the stock for 10 or more generations. The breeder who had used three
heterozygous sires in succession during almost 12 yr. increased the frequency of the
defective gene to almost the theoretical limit, which had probably been reached in
the purebred Jersey herd from which the sires were purchased. The lethal was
not comparable to those reported in rodents and other mammals.
Rental rate plan for bulls used in artificial insemination, J. W. BARTLETT and
E. J. PERRY. (N. J. Expt. Stas.). (Jour. .Anim. Sci., 3 (1944), No. 3, pp. 283286).-The
rental plan for the use of semen of bulls in the New Jersey Breeding
Association No. 1 is based on fixed charges of $3 for proved bulls, and for unproved
bulls 50 ct. for 1- to 2-year-old bulls, 75 ct. for 2- to 3-, $1 for 3- to 4-, $1.25 for
4- to 5-year-old bulls, and $1.50 for bulls 5 yr. of age and over. There were added
to these amounts for proved bulls 2 ct. for each percentage point that the first
daughter's fat production is above the breed average for age and class, and 4, 6,
8, and 10 ct. that the first 2, 3, 4, and 5 or more daughters' fat production is above
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5064/m1/47/: accessed January 20, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.