Experiment Station Record, Volume 92, January-June, 1945 Page: 36
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36 EXPERIMENT STATION RECORD [Vol. 92
2,396 pigs in the study. The inbreeding of the pigs was about 21 percent. The"
regression of rate of gain from weaning to 200 lb. on the inbreeding computed
within years and lines was -0.0022 0.0010, indicating the expected amounts of
decline in growth rate with inbreeding without selection. The mean growth curve
with the twentieth and fortieth percentiles above and below the mean were plotted.
The pigs of sows were about 4 lb. heavier at weaning (56 days) than the pigs of
gilts, a difference which was' maintained at least to 168 days. Age differences of the
dams accounted for 22 percent of the intraline and year variance in weaning weights,
but there was little effect on later weights. Variance due to common environmental
conditions within each litter was greatest at 21 days and accounted for 37 percent of
the total variance. In gains it decreased from 24 percent 28 days after weaning to
7 percent 112 days after weaning. Analyses of variance of gains 28, 56, 84, and
112 days after weaning indicated that 18, 28, 39, and 45 percent, respectively, of the
variability was hereditary. Variances in gains from birth to 200 lb. and weaning to
200 lb. were 21 and 40 percent hereditary, respectively. Differences between estimates
of hereditability containing and not containing preweaning growth are overestimates.
The hereditability of post-weaning gains' is greater than post-weaning weights.
Seasonal incidence of anestrus in the postpartum rabbit, J. T. BRADBURY.
(U. S. D. A.). (Anat. Rec., 88 (1944), No. 4, p. 424).--Among 156 does having
litters from June 1942 through May 1943, 50 percent of those having litters in
October and November were anestric. The lowest number of anestric does was 6
percent in those with litters born in February and March. The average weights
in the anestric and estric does were, respectively, pituitary 32 and 50 mg., ovary
0.37 and 1.02 gm., and uterus 5.4 and 14.9 gm. The differences in size and tonic
condition of the uterus make it possible to judge quickly the sexual condition of
Evidence for early testis hormone secretion in the rat from a study of the
epididymis, E. S. CIESLAK (Endocrinology, 35 (1944), No. 1, pp. 63-67).-Castration
of male rats at 1 day after birth caused a consistent decrease in the weight of
the posterior portion of the epididymis as ascertained in normal and castrated rats
autopsied at 8 to 45 days of age. Daily injections of 0.01 mg. of testosterone propionate
caused increases in the weight of the epididymis of castrated rats. Hormone
secretions by the testis can be detected by the eighth day of life. 'The studies were
conducted with 96 castrated and control rats.
Effectiveness of blood and hemin for augmentation of pituitary gonadotropic
extracts in the male, R. K. MEYER, W. H. MCSHAN, and L. E. CASIDA. (Univ.
Wis.). (Soc. Expt. Biol. and Med. Proc., 52 (1943), No. 2, pp. 78-80).-The
testes, seminal vesicles, and prostate glands were heavier from rats receiving extracts
of unfractionated sheep pituitary with hemin than pituitary extract alone,
showing augmentation of the hemin on the gonadotropic effect of the pituitary.
The differences in the effects of doses of 100 and 200 mg. of the pituitary were not
significant with 10 rats injected with each sized dose. The weights of the testes
of immature chickens and pigeons were not further increased when hemin or blood
was combined with the extract.
A study on inactivation of ovarian hormones by the liver, P. ENGEL
(Endocrinology, 35 (1944), No. 1, pp. 70-72).-The atrophy of the uteri of rabbits
whose ovaries had been transplanted into the mesentery was like that in spayed
animals, but a normal uterus was maintained when the ovaries were transplanted
into the large muscle of the back. Liver pulp placed'in contact with estrogen inactivated
it, but the liver pulp had no effect on progesterone. A total of six animals
was employed in the investigation.
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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/m1/49/: accessed June 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.