Michael L. Thonney - Professor
PhD from University of Minnesota
Graduate fields: Animal Science, Nutrition
Area(s) of interest: management of highly productive sheep, growth and development, ruminant nutrition, skeletal growth.
Email: mlt2@cornell.edu
Current Research
Research is conducted on management, health, nutrition, and genetics of highly productive sheep and on gene regulation of muscle growth of domestic animals.
Purebred Dorset and Finnsheep flocks and a commercial Finnsheep x Dorset flock are managed under the Cornell STAR system to provide animals to evaluate strategies to make efficient use of labor and to better control health problems. Selection in the Dorset and Finnsheep flocks is for aseasonality and fertility. Growing lambs are used to evaluate dietary ingredients such as fish meal to provide rumen-escaped protein, barley in diets for lambs in the northeast, and source and level of dietary fiber. Experiments are underway to document a new approach for balancing ruminant diets based upon proportions of nonstructural carbohydrates and fermentable NDF, rather than limiting animal production to a predefined intake of energy.
A differential ovine muscle growth model was used recently to understanding gene regulation of muscle growth with the objective of increasing lean meat production at the same degree of maturity in farm animals. A former graduate student, Raluca Mateescu, compared the splenius muscle of the neck, which responds to testosterone by increasing rate of hypertrophy, to the semitendinosus muscle of the leg for which the growth pattern remains unchanged. Expression of the IGF-I, androgen receptor, and myostatin genes was measured by ribonuclease protection and competitive reverse-transcriptase PCR assays. Our results showed that locally produced IGF-I and the regulation of AR, but not myostatin, expression may be important for sexually dimorphic muscle growth patterns.
Most of the sheep at the Cornell Sheep Farm have been involved in three major projects. A recently completed vaccination trial against Johne's Disease showed that a currently available cattle vaccine can be used to control Johne's Disease in sheep. A backcrossing experiment is underway to investigate candidate genes and identify QTL markers for aseasonal lambing and milk production. The entire ewe flock at the Cornell Sheep Farm is being used to test an autogenous vaccine to control lamb pneumonia in a major new project in collaboration with colleagues in the College of Veterinary Medicine.