Research Accomplishment Reports 2007

Genetic Selection and Crossbreeding to Enhance Reproduction and Survival of Dairy Cattle

A.J. McAllister
Department of Animal and Food Sciences

 

Project Description

The project was undertaken to address issues of declining fertility and premature culling of dairy cattle. Examination of crossbreeding as an option to address these issues is the basis of this project. It has been conducted as part of regional project S-1008 in collaboration with Virginia Polytechnic and State University and North Carolina State University.

The breeding plan design has involved the mating of purebred Holstein and Jersey dams and the production of offspring in four genetic groups at the University of Kentucky: Holstein (HH) - 36 male, 32 female; Holstein X Jersey crossbred (HJ) - 23 male, 19 female; Jersey X Holstein crossbred (JH) - 25 male, 18 female and Jersey (JJ) - 16 male, 22 female. The females (N=91) of the four genetic groups (HH, HJ, JH and JJ) constituted the females for production of the next generation of males and females. All calves in the four genetic groups have been born. Evaluation of calving performance of purebred dams when giving birth to either purebred or crossbred calves and early calf growth and immune function was completed. Determination of age of onset of puberty has been made. Heifer growth, health and reproduction measurements have been completed for all but 13 heifers that are yet to calve. Collection of calving data, lactation data and post-partum reproduction measurements is proceeding.

The second generation of the experiment began with the mating and subsequent calving of the females of the purebred and crossbred genetic groups previously described. In addition to the purebred Holstein and Jersey females, the two crossbred groups of females were and are still being mated to a third breed to produce three-way cross calves. Thirteen Brown Swiss-sired and 3 Scandinavian Red-sired heifers have been born out of 40 heifers expected to be produced. Fourteen Holsteins and three Jerseys have been born out of 20 purebreds expected of each breed.

Impact

A collaborative study with the Virginia herd showed that in comparisons of the purebred cows and heifers giving birth to purebred and crossbred calves that Holstein additive effects were greater for birth weight than Jersey but were associated with higher levels of calving difficulty and stillbirths. For breed maternal influences higher birth weights were associated with Holstein but less calving difficulty and fewer stillbirths were associated with Jersey. At Kentucky, breed additive contributions for heifer growth traits through 8 weeks of age favored Holstein over Jersey while maternal contributions favored the Jersey. The crossbred calves demonstrated hybrid vigor by having superior gain from birth to 56 days of age as a percentage of birth weight than the average of the purebreds.

Various measures of immune function in calves from birth to 8 weeks of age at Kentucky showed differences among breed groups. HH were the highest and JJ the lowest for peripheral blood granulocytes which represent phagocytic number. JH had the highest antibody producing cells and JJ the highest total T-cells. While serum proteins did not differ among breed groups, the total immune globulin concentration was higher for the HJ and JH groups compared to HH and JJ. Fecal score, done daily from birth through 56 d, were averaged weekly and revealed a possible maternal effect which favored Jersey. A phagocytosis assay was also used to assess immune function of the different breed groups and the underlying genetic effects. Including both adhered and engulfed cells, HJ had the greatest phagocytic activity while the breed groups did not differ in phagocytic + killing activity and hence there was no evidence for any of the genetic effects. However, there was evidence for heterosis for phagocytosis. When only engulfed cells were measured, there were no differences among the breed groups for phagocytic + killing activity but the HJ and JJ groups had the highest phagocytic activity. There was a significant maternal effect favoring Jersey for phagocytic activity. Age at puberty was determined for the purebred and crossbred genetic groups from all three university herds. The breed groups with significant additive and heterosis effects were: HH = 349 plus/minus 11.2 d; HJ = 315 plus/minus 11.0 d; JH = 304 plus/minus 11.7 d; and JJ = 300 plus/minus 10.8 d. Also, proportions of heifers pregnant after 2 services differed by breed group with significant heterosis: HH = 83.6%; HJ = 91.7%; JH = 91.1%; JJ = 66.7%. Results to date have shown significant heterosis for several traits which could be beneficial for dairy cattle performance.

Dairy crossbreeding is being increasingly practiced in the dairy industry in the US. The results of this project will provide information for dairy producers to use in choosing the breeds and crossbreeding system should they adopt crossbreeding in their dairy farm business as they seek to develop a more efficient and profitable dairy production system.

Publications

Cassell, B., McAllister, A., Nebel R., Franklin, S., Getzewich, J., Ware, J., Cornwell, J. and Pearson, R. 2005. Birth weights, mortality and dystocia in Holsteins, Jerseys and their reciprocal crosses in the Virginia Tech and Kentucky crossbreeding project. J. Dairy Sci. 88(Suppl. 1): (Abstr.). 100th Annual Meeting of ADSA. Cincinnati, OH. July 24-28.

Ware, J.V., Franklin, S.T., McAllister, A.J., Jackson, J.A., and Cassell, B.G. 2005. Performance of Holstein and Jersey calves compare with performance of Jersey x Holstein and Holstein x Jersey calves. J. Dairy Sci. 88(Suppl. 1): (Abstr.). 100th Annual Meeting of ADSA. Cincinnati, OH. July 24-28.

Ware, J.V., Franklin, S.T., McAllister, A.J., Jackson, J.A., Meek, K.I. and Cassell, B.G. 2005. Evaluation of immunological differences among Jersey, Holstein, and crossbred calves. J. Dairy Sci. 88(Suppl. 1): (Abstr.). 100th Annual Meeting of ADSA. Cincinnati, OH. July 24-28.

Cassell, B.G., Olson, K.M. and McAllister, A.J. 2007. Comparison of yield in Holsteins, Jerseys and reciprocal crosses in the Virginia Tech -Kentucky crossbreeding trial. J. Dairy Sci. 90(Suppl. 1): (Abstr.). Joint Annual Meeting ADSA, PSA. AMPA, ASAS. San Antonio, TX July 8-12.