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The objective of the present research was to clarify the basis for the difference in performance of turkey toms characterized as low or high semen volume producers. Variables measured included testicular weight, deferent duct semen volume, and deferent duct morphology based upon plastic casts. Three organizational patterns emerged after viewing plastic casts of deferent ducts: helical, serpentine, and randomly folded coil. The randomly folded coil was the principal pattern in deferent ducts from low and high semen volume producers alike. No difference in patterns was observed between low and high semen volume producers. Differential semen yield was attributed to a greater testicular mass along with a greater storage capacity of the deferent duct in high semen volume producers. However, deferent duct storage capacity appeared to be the predominant factor affecting semen yield.

Studies were conducted to determine if high and low ejaculate volumes were associated with differences in testicular weight and ductus (d.) deferens semen volumes. Mature male breeder turkeys were classified as low (less than or equal to .22 ml) or high (greater than .30 ml) semen producers. One week after or immediately after the last semen collection the turkeys were killed, testes weighed, and d. deferens and ejaculate semen volumes and sperm concentrations determined. Comparisons of low (LSP) and high (HSP) semen producers showed no differences in testes weights and sperm concentration in d. deferens. However, LSP turkeys had a lower volume of semen in the d. deferens and ejaculated a lower percentage of that volume than did HSP turkeys (P less than .05). Although the sperm concentrations of HSP and LSP were the same, the total number of sperm in the ejaculate of LSP was less than the HSP and was also less when calculated as a percentage of the sperm in the ejaculate plus d. deferens. These studies indicate that both a decreased reservoir of semen in the d. deferens and a lower efficiency of removal of semen from the d. deferens contribute to the decreased ejaculate volume of LSP.

An experiment was conducted to study the effects of feeding diets composed of triticale (var: Flora) with varying ME levels and 7% CP on fertilizing capacity and semen quality of Medium White breeder toms. Thirty-nine breeder toms were fed ad libitum from 30 to 54 wk of age one of four dietary treatments: 14% CP with 2,892 kcal ME/kg; 7% CP with 2,919 kcal ME/kg; 7% CP with 2,719 kcal ME/kg; and 7% CP with 2,539 kcal ME/kg. Semen volume (SV), packed spermatozoa volume (PSCV), BW, testicular weight (TW), and fertilizing capacity of semen were measured. No differences for SV, PSCV, TW, calculated daily feed, and estimated energy consumption were observed among the dietary energy levels fed. The estimated daily protein intake was higher (P less than .05) for toms fed the 14% 2,892-ME diet than 2,539, 2,719, and 2,919-ME diets containing 7% CP. The 7% 2,919-ME diet reduced (P less than .05) the fertilizing capacity of spermatozoa, whereas the 7% 2,539-ME diet decreased the percentage of fertile eggs hatched. Under the conditions of this experiment, Medium White breeder toms maintained fertilizing capacity and semen quality when provided a diet containing 7% CP with 2,719 kcal ME/kg.

Two strains of cockerels were used to evaluate the effect of complete or partial caponization (i.e., removal of either left or right testicle) on growth rates, feed conversions, dressing yields, and texture and sensory properties of the meat. In Experiment 1, where Hubbard White Mountain cockerels were used, partially and completely caponized birds had better feed conversions and were heavier at time of slaughter than roosters. In Experiment 2, where Penobscot birds were used, birds with the right testicle removed gained the most weight and had the best feed conversion ratio; capons were second best. In both experiments, when only one testicle was removed, the other testicle doubled in size so that the testicular weight was equivalent to that of roosters. Results from sensory panels and shear tests indicated that meat from capons was consistently the most tender; this difference was most pronounced in thigh meat. Meat from “slips”, or partially caponized birds, was less tender than capon meat but as tender as or more tender than meat from roosters. Correlation coefficients were prepared to compare results of subjective (sensory) and objective (shear) analyses. Sensory evaluations were more highly correlated with multiple-bladed shear tests than with single-bladed shear tests.

ALTHOUGH darkness allegedly inhibits egg production, our previous work (Wilson and Abplanalp, 1956) showed that pullets would lay eggs with a daily ration of six minutes of light in 24 hours. Rearing pullets in darkness does not prevent them from coming into egg production according to Rider (1938). Continuous darkness actually produced maximum testicular weight in the parakeet, Melapsittacus undulatus, in the experiments of Vaugien (1953). The purpose of these tests was to determine the length of time hens would remain in production when subjected to complete darkness. EXPERIMENTAL Two tests were made in which S. C. White Leghorn laying hens in cages spent a 5-week period in complete darkness. The first test was with 60 hens kept in three separate pens of 20 hens each. From 17 to 38 weeks of age these hens had been given alternately two hours of light and two hours of darkness. They had . . .