Prof. David Wolfenson

Research Interests:

My research centers on reproduction in the dairy cow. I focus on the two major stresses affecting reproduction and fertitliy of cows - environmental heat stress and pathogenic stress.

  1. Regarding heat stress, we characterized impairments of follicular and luteal functions related to steroidogeneis, attenuation of follicular dominance and other preovulatory follicle-related functions.
  2. Regarding subclinical, chronic mastitis, we found that 1/3 of mastitic cows exhibited delayed ovulation. This syndrome involves disruption of follicular steroidogeneis, low gene expression in theca and granulosa cells and low and delayed LH surge.
  3. Attepts to improve fertility of subclinical mastitic cows are currently examined.
  4. We found that small early antral follicles are susceptible to long-term, exposure to minimal doses of both Gram-positive and Gram-negative toxins, and the induced damage is then carried over to the preovulatory follicles, corresponding well with the long-term chronic nature of subclinical mastitis.
  5. We also found lack of association between clinical mastitic events and premature induction of luteal regression, suggesting that the main cause of low fertility caused by E. coli mastitis post-AI is directed at the embryo rather than the corpus luteum.

 

David Wolfenson

Curriculum Vitae

Degrees:

1980 - Ph.D. Physiology, Faculty of Agriculture, The Hebrew University

1974 - M.Sc. Animal Sciences, Faculty of Agriculture, The Hebrew University

1971 - B.Sc. Animal Sciences, Faculty of Agriculture, The Hebrew University

Teaching Responsibilities:

71803 - Reproductive Biology

71833 - Bioclimatology

71812 - Dairy Cattle Management

71926 - Environmental Physiology 

Short summary:

Professor in Animal Physiology, in the Faculty of Agriculture, Food and Environment of the Hebrew University, in Rehovot, Israel. Teaching includes: Comparative Reproductive Biology, Environmental Physiology and Dairy Cattle Physiology and Management. In the last 10 years I have supervised 12 M.Sc, 2 D.V.M. 3 Ph.D., and 2 undergraduate students. Publications include 6 chapters in books, 70 scientific papers and review papers in peer-reviewed journals, and 72 abstracts at scientific meetings.

David Wolfenson

List of Publications

  1. Wolfenson, D., Z. Roth, and R. Meidan. Impaired reproduction in heat-stressed cattle: basic and applied aspects. 14th Int. Cong. Anim. Reprod. Stockholm. Anim. Reprod. Sci. 60-61, 535-547, 2000. (review).
  2. Shaham-Albalancy, Y. Folman, M. Kaim, M. Rosenberg, and D. Wolfenson. Delayed effect of low progesterone on bovine uterine prostaglandin F2 secretion in the subsequent oestrous cycle. Reproduction 122: 643-648, 2001.
  3. Roth, Z., A. Arav, A. Bor, Y. Zeron, R. Braw-Tal, and D. Wolfenson. Improvement of quality of oocytes collected in the autumn by enhanced removal of impaired follicles from previously heat-stressed cows. Reproduction, 122: 734-744, 2001.
  4. Wolfenson, D., H. Sonego, A. Bloch, A. Shaham-Albalancy, M. Kaim, Y. Folman, and R. Meidan. Seasonal differences in progesterone production by bovine luteinized thecal and granulosa cells. Dom. Anim. Endocrinol. 22: 81-90, 2002.
  5. Wolfenson, D. Effects of heat stress on bovine ovarian functions. Trends in Comp. Biochem. Physiol., 8:159-164, 2002. (review).
  6. Kaim, M., A. Bloch, D. Wolfenson, R. Braw-Tal, M. Rosenberg, H. Voet and Y. Folman. Effects of GnRH Administered to Cows at the Onset of Estrus on Timing of Ovulation, Endocrine Responses and Conception Rates. J. Dairy Sci., 86:2012-2021, 2003.
  7. Bloch, A., Folman, Y., Kaim, M., Roth, Z., Braw-Tal R., and Wolfenson, D., Endocrine alterations associated with extended time interval between estrus and ovulation in high-yield dairy cows. J. Dairy Sci. 89:4694-4702, 2006.
  8. Wolfenson, D. Factors associated with low progesterone concentrations and their relation to low fertility of lactating dairy cows. Israel J. Vet. Med. 61:37-40, 2006. (review).
  9. Lavon, Y., Leitner, G., Goshen, T., Braw-Tal, R., Jacoby, S., and Wolfenson, D. Exposure to endotoxin during estrus impairs reproductive functions in dairy cows. Theriogenology 70:956-967, 2008.
  10. Lavon, Y., Leitner, G., Voet, H., and Wolfenson, D. Naturally occurring mastitis effects on timing of ovulation, steroids and gonadotrophic hormone concentrations, and follicular and luteal growth in cows. J. Dairy Sci. 93:911-921, 2010.
  11. Lavon, Y., Leitner, G., Klipper, E., Moallem, U., Meidan, R., and Wolfenson, D. Subclinical, chronic intramammary infection lowers steroid concentrations and gene expression in bovine preovulatory follicles. Domest. Anim. Endocrinol. 40:98-109, 2011.
  12. Lavon, Y., Leitner, G., Moallem, U., Klipper, E., Voet, H., Jacoby, S., Glick, G., Meidan, R., and Wolfenson, D. Immediate and carryover effects of Gram-negative and Gram-positive toxin-induced mastitis on follicular function in dairy cows. Theriogenology 76:942-953, 2011.
  13. Lavon, Y., Ezra, E., Leitner, G., and Wolfenson, D. Association of conception rate with pattern and level of somatic cell count elevation relative to time of insemination in dairy cows. J. Dairy Sci, 94:4538-4545, 2011.
  14. Wolfenson D. and W.W. Thatcher. Strategies for improvement of thermal and reproductive responses under heat stress. In: Environmental Physiology of Livestock, R.J. Collier with J.L.Collier, editors. Wiley-Blackwell, UK, 2012. 
David Wolfenson