The Relation of Certain Semen-quality Tests to Breeding Efficiency and Characteristics of Semen from Low-fertility Bulls Before and After Hormone Injection

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Abstract
Simple correlations between laboratory semen-quality tests and breeding efficiency in dairy bulls are as follows: motility, r = 0.015; concn., r = 0.078; percentage dead, r = - 0.51; fructolysis index, r = - 0.018; percentage abnormal sperm, r = - 0.83. 55 samples from 12 bulls and 1010 breedings were used in the study. All of these bulls were normal fertile bulls and the breeding efficiency for individual samples ranged from 87 to 55%. Injns. of follicle stimulating hormone, lyophilized beef anterior pituitary, and pregnant mares'' serum increased the concn. of spermatozoa from 3 bulls of low fertility of genetic origin. Other characteristics of the semen did not become normal, indicating other deficiencies.