An artificial vagina has been designed at Cornell for use with bulls to avoid subjecting the semen to too sudden a change in temperature. It is useful particularly in cold weather. The device has a water jacket made like the conventional artificial vagina, but has also a second inner lining of tubing. The tube is tapered at one end by cutting out a V-shaped piece and cementing the cut edges together with rubber cement, leaving an opening at the end small enough to hold the open end of the test tube. In cementing the edges, a small hole is left at the apex of the V-shaped cut to allow the escape of air when the bull thrusts his penis into the artificial vagina. The need for the small hole is questionable, however, because vaginas both with and without the opening have been used successfully. The large end of the inner lining is doubled back over the end of the water jacket. Water is poured through a hole in the outer hose located near enough to the end to be covered by the rubber tubing when doubled back. This device is used in the same way as the artificial vagina in common use. It is somewhat bulky to handle and requires a little more skill in its manipulation than the older model.

Waxed paper or cellophane capsules are being used extensively in Denmark and Russia for packaging semen. Each capsule contains one dose, and a gun of the type developed by Eduard Sorensen of Denmark is used for pushing the semen directly from the capsule into the cervix. This eliminates the use of glassware in storage and during insemination, and the procedure appears to be yielding satisfactory results.

Most artificial breeding associations maintain two or more bulls. These bulls may vary considerably in breeding merit, and a problem arises concerning the amount to charge for semen from each bull. Bartlett and E. J. Perry proposed a plan for charges based on performance of proved bulls and performance of ancestors of unproved bulls. Under this plan a basic charge is made per service from unproved bulls and a higher basic charge per service from proved bulls. Besides the basic rate, a charge is made on the basis of the production records of daughters of proved bulls. For unproved bulls, the basic rate is increased annually up to 5 years of age, and in addition a charge is made in accordance with the productivity of relatives of the bull, including dam, sisters, and half-sisters. Records are considered in relation to the breed average.

The possibilities of controlling certain diseases by using artificial insemination have been investigated. After experience with 12 herds in Missouri, H. A. Herman, E. R. Berousek, and E. W. Swanson suggested that artificial insemination can control vaginitis and trichomoniasis, besides reducing the number of repeated services, and the intervals between calving.

Workers in Peru have encountered considerable difficulty with low fertility and sterility in rams at high altitudes. C. Monge and M. San Martin studied the semen of two rams imported from Chile to Peru and placed at 10,500 feet elevation. Both lacked spermatozoa at first. In one ram spermatozoa appeared later, and the pH ( roughly, the degree of acidity), sperm concentration, and motility approached normal values. The semen of the other ram contained no spermatozoa after 5 months, but the animal at no time suffered any decrease in sexual drive. San Martin and J. Atkins compared the semen of imported rams kept at an altitude of 14,750 feet in Peru and of their offspring, with rams kept at sea level. Only 15 of the 58 rams studied at high altitudes had semen with optimal biological properties. Samples of semen showed a wider variation of pH, increased leucocytes and epithelial cells, decreased motility and viability, and the appearance of more juvenile forms, compared to that of rams kept at sea level. Of 59 ewes that supposedly were infertile at high altitudes, 51 became pregnant when they were artificially inseminated with semen of good quality. These workers concluded that reduced fertility at high altitudes is due to abnormalities in semen.

Similarly, F. Accame, Luis Monge, and J. C. Miller studied the effects of reduced barometric pressure on the semen of rams. No injurious effects of low pressure could be detected and the workers concluded that at high altitude fertility was impaired otherwise than by direct effects on the sperms.

L. Hansen Larsen and Eduard Sorensen conducted a series of experiments in Denmark to determine the importance of the amount and kind of protein in the diets of bulls. They concluded that the content of digestible protein in the ration regulates semen production. In all their experiments, a high content of digestible protein resulted in an improvement in the fertilizing capacity of semen. They could not determine, however, whether animal protein was more effective than plant protein. In this work the amount of digestible protein fed daily per animal ranged from 538 to 1,230 grams. The fertilizing capacity of the semen was evaluated by measuring the dehydrogenation activity of the spermatozoa, using the methylene-blue test.

The effect of size of dose has been studied by two Russians. I. I. Sokolovskaja and M. J. Solovei gave doses of semen containing varying numbers of spermatozoa to 12 Angora rabbits. Each produced 3 litters as a result of artificial insemination and a fourth litter from natural mating. These workers report that apparently normal results were obtained when the amount of semen contained 100,000 to 100,000,000 spermatozoa, but more or fewer sperms than that lowered the rate of conception and increased abortion. Solovei inseminated 4 female rabbits with 25,000 to 50,000 spermatozoa, but the does aborted or delivered young that were weak or dead. Two rabbits that for comparison received 500 million spermatozoa each produced normal litters. This dosage is considerably higher than the one that Sokolovskaja and Solovei report as giving normal results. Solovei also worked with swine. Seven sows were inseminated with 10,000 million or 20,000 million spermatozoa, and only two conceived. Five control sows received 70,000 million or 120,000 million sperms, and all conceived. These results are based on limited numbers and may be explained by factors other than those under investigation.

V. K. Milovanov reported great differences in the quality of offspring from female rabbits inseminated with semen that had been stored at 12°-18° C. under aerobic and anaerobic conditions—that is, with and without oxygen. In the latter group, 7.2 young were born in a litter, compared to 3.2 in the aerobic group and 8.0 in natural coatings. Half of the young of the anaerobic group died in the first 4 months, but only 1 out of 13 young died in the aerobic group. Among the control animals, one-fourth died.

Solovei inseminated five groups of rabbits—which ovulate after copulation-10, 20, 25, 30, and 40 hours before ovulation. Half were killed and dissected at different times during pregnancy; the others went to term. In the first group, inseminated at 10 hours, all became pregnant and all the females that went to term produced seven to nine healthy young. In the second group, one female was barren, one had seven normal young, and the others had weak or dying offspring, or a reduced number of degenerating embryos. Similar results were obtained in the third group. Only two of the fourth group were pregnant and only two degenerating fetuses were found in one of them. None in the fifth group was pregnant.

The results summarized in the four preceding paragraphs were based on limited numbers and obviously need to be checked in further experiments on larger numbers of animals. They do indicate, however, the possibility that improper manipulation of semen may result in defective offspring and hence the need for very careful experimental work before drawing conclusions.