Areas of Research Interest
A.    Relationship between bovine seminal quality with spermatozoal freezing characteristics.
B.    Spermatozoal morphology relationship to DNA content.
C.    Spermatozoal abnormality relationship to non-DNA nuclear composition.
D.    Spermatozoal membrane composition relationship to freezability.
E.    Spermatozoal physiology with fertility.
F.    Heritability of various seminal quality characteristics.
G.    Relationship between bovine seminal quality and genetic transmitting ability for economically important production traits.
H.    The relationship of seminal quality to testicular and epididymal function.
I.    Use of dairy herd improvement association (DHIA) data as a source for estimating bull fertility (Non-return rate) in breeding technician devoid areas.
J.    The effect of thawing times and temperatures on the quality and fertility of frozen bovine semen packaged by various methods and containers.
K.    The effect of gossypol in cottonseed containing diets on seminal quality and spermatogenesis in the dairy bull.
L.    The effect of gossypol in cottonseed diets on plasma levels of luteinizing, follicle-stimulating and testosterone hormones and cholesterol in bulls.

    RESEARCH ACCOMPLISHMENTS
    In a continuing effort to optimize the bovine male role in efficiency aspects of reproduction, the semen physiology laboratory has shown that nanovid microscopy, a new method of microscopy, is useful in the evaluating the sperm membrane involvement in the fertilization process. Additionally, since head (primary) abnormalities of bull sperm have been shown to have a relatively high degree of heritability, and associated with a reduction in fertility due to embryonic mortality, our work has been directed at the use of an image analysis system to evaluate sperm head shapes. The technology objectively verified that abnormally shaped sperm are quite distinguishable from normally shaped cells, and the difference can be used as an improved screen of semen to be used in artificial insemination.
    Bovine semen quality change with age has been evaluated to show that it does change with age and the age effects vary across bulls. Semen quality from young bulls could not predict quality at a later age. Therefore, it is necessary to have a stringent quality control program for bull evaluation before progeny testing. This will prevent low fertility bulls from entering the marketplace and insure the greatest degree of success in the artificial insemination program in this state as well as the nation.
    Research on the exchange of seminal plasma between high and low fertility bulls showed no difference in sperm quality parameters. Incubated semen quality was higher for high fertility bulls than for low fertility ones. The Na concentration was higher for high fertility bulls and K concentration was higher for low fertility bulls.

SEMEN SEX SEPARATION
    Additionally, we are using the videomicroscopy image analysis system to verify value-added post collection techniques applied to bovine semen which separate sperm cells based on presence of X or Y chromosome. This could increase the annual sale of bull semen by about $50 million and improve the production efficiency of the dairy farmer.
    Experiments were run to determine separation efficiency of X and Y bearing spermatozoa with the SEPDEVICE (Pat. Pend.) column, using video enhanced contrast microscopy (VECM) combined with video intensified fluorescent microscopy (VIFM) for evaluation. The differences in head area and fluorescent intensity indicated a successful separation based on size differences between the X and Y chromosome bearing spermatozoa. Variation in separation efficiency across bull-ejaculate combinations occurred to different degrees. Some ejaculates may have more or less Y- bearing sperm than do other ejaculates. Thus different separation efficiencies would be expected. A significant deviation of the sex ratio in favor of either sex would benefit the livestock industries. With VECM/VIFM image analysis it was possible to detect the subtle differences in head area and fluorescent intensity of spermatozoa separated by SEPDEVICE.


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