Semen Quality Characteristics and FertilityThe selection of males for breeder flocks is usually based on such characteristics as posture, body conformation, maturity, body size, ~~~~ ~ ~ ~ *Ha. Agr. Exp. Sta. Journal Series No. 1062. 95 96condition of the legs and feet, appearance of the head, general health and vigour, and appearance of eyes. Although these characteristics are useful in selecting males they do not assure that high fertility will be obtained. Several attempts have been made to relate various semen quality characteristics to fertility. There is much disagreement in the literature, however, regarding the importance and reliability of semen traits in predicting fertility. Differences can, of course, be expected between the results obtained from natural mating and artificial insemination. Although measurements of semen traits have been succcssful in detecting sterile birds, the prediction of fertilizing capacity appears to be complex and influenced by numerous factors other semen quality.In order to make fertility predictions or male breeding worth predictions based on semen evaluation, high correlations between semen characteristics and fertility must be found. Then a statistical model may be fitted using the semen quality values as independent variables to define the dependent variable, fertility. In addition, when attempting to obtain an estimate of fertility or breeding potential, one must keep in mind that it is influenced by genetical, physiological and social factors.Semen quality characteristics are generally believed to be inherited (Lake, 1971; Marini and Goodman, 1969) and differences in semen characteristics and fertility have been reported between breeds (Parker et al., 1942;Allen and Champion, 1955; Taneja and Gowe, 1961 a and b;McDaniel and Craig, 1962), between inbred lines (Williams and McGibbon, 1956; De-Silva, 1963) and between families (Boone, 1968).Heritability values for such traits as semen quantity, concentration and motility were found to be high (Soller et al. 1965b) as were the repeatabilities of such measurements. Nestor and Brown (1976a) reported that measurements of semen quality made early in the reproductive life of the male were not closely correlated with subsequent evaluations and did not permit accurate prediction of future semen production. Nestor (1976) successfully selected turkeys for increased semen yield, however, there were no consistent changes in percent fertility, percent hatchability of fertile eggs or number of poults per hen associated with the increases in semen yield. Some success also has been reported for the selection for fertility when using frozen chicken semen (Scott et al., 1977).Concentration of spermatozoa in semen has been claimed to be significantly related to fertility (following AI), having a correlation coefficient of 321 (Kamar, 1960) and .481 (Boone, 1968). Others have presented data indicating that it is not significantly related to fertility (

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Two experiments were conducted with commercial Leghorn-type hens in advance state of production (16 months of age) to determine response to a 16% protein, corn-soy diet with no added salt. There was an immediate and significant decline in feed consumption. Body weight decreased significantly. After 14 days, there were no ova in the rapidly maturing stage. The ovary may have been reduced in size but apparently was not regressed. Egg specific gravity was significantly reduced but egg weight was unaffected. Egg production dropped to 0% in 17-21 days. On the return of 0.25% salt to the diet, recovery as measured by production rate was initiated immediately with production reaching 79% in 16 days compared to a pre-experimental production of 68%.

Two experiments were conducted to determine if Bobwhite quail chicks would adjust feed consumption according to energy intake from hatching to five weeks of age. Three starter diets, which were calculated to contain 2850, 3010 and 3170 Kcal. M.E./Kg., were fed throughout the five-week experiments. As energy was increased, the protein level was increased proportionally. Each treatment group consisted of four replicate pens containing 125 chicks each. Body weight at two and five weeks of age was not affected by treatment, except for a reduction at two weeks for birds on the 3170 Kcal./Kg. diet. There were no significant treatment effects on mortality. The feed consumed/bird/day decreased as dietary energy was increased. The calculated energy consumption/bird/day was 15.44, 15.31 and 14.79 Kcal., respectively, for the 2850, 3010 and 3170 Kcal. M.E./Kg diets during the five-week period. The energy and protein consumption per gram of body weight was slightly reduced at the high energy level indicating a more efficient use of energy and protein of the high energy diet. These data indicate that the Bobwhite quail adjusts feed intake according to the energy content of the diet.

Five experiments were conducted to compare the effects of various incubation temperature combinations on the hatchability of Bobwhite quail eggs. A starting incubation temperature of 40.6 C resulted in numerically lower hatchability. Incubation at 37.5 C resulted in a greater number of pipped, unhatched eggs, and a later, less uniform hatch. Temperatures during the hatching period (22 to 25 days of incubation) of 36.9 C and 38.1 C resulted in lower hatchability than the hatching temperature of 37.5 C.