Department of Population Medicine and Diagnostic Sciences
Contact Information: Email: email@example.com, Phone: 607-253-4391
Sponsor: Cornell University, College of Veterinary Medicine, Research Grants Program in Animal Health
Grant Number: N/A
Title: Efficiency of Metabolism Regulation during Negative Energy Balance and Heritability of Energy Related Metabolites in Transition Dairy Cows
Annual Direct Cost: $47,075
Project Period: 10/01/2012-09/30/2014
DESCRIPTION (provided by applicant): The ability of dairy cattle to adapt to the natural change in energy balance as they transition from late gestation to early lactation is important as the energetic demands for milk production cannot be met by feed intake alone. Inappropriate adaptation to this period of negative energy balance can lead to excessive postpartum elevation of non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA) which are associated with negative downstream health events, poor reproductive performance, and a loss of milk production. However, these metabolites from negative energy balance are not well correlated (i.e. some cows with high NEFA have low BHBA and vice versa), and it is still unknown why some cows with elevated NEFA transition well into early lactation while others do not. Identification in mice of fibroblast growth factor-21 (FGF21), a potent regulator of metabolism, has been suggested as a marker of oxidative capacity in liver and is induced in conditions associated with extensive lipid use. Thus, FGF21 may play a role in the ability of dairy cattle to mobilize and effectively convert NEFA from adipose tissue to usable energy without an overproduction of ketone bodies (e.g. BHBA). In addition to the role of FGF21 in an individual cow, genetic evaluation of body condition score, NEFA, and BHBA have shown that significant genetic variance exists, especially during the first weeks of lactation. Although it is unknown whether FGF21 has a genetically heritable component, the high-yielding dairy cow offers distinctive advantages for exploring the role of FGF21 in lactation as it depends more extensively on lipid reserves for lactation success than either the mouse or rat. Additionally, some dairy cows are susceptible to pathologic changes in early lactation such as fatty liver that have been traced to processes regulated by FGF21, namely lipolysis in adipose tissue and triglyceride deposition in the liver.
Within the proposed 2-year funding period, we specifically aim to:
All aims will be completed via epidemiologic cohort studies. Aim 1 will be achieved using previously collected serum samples from 544 dairy cattle in New York State that have at least 5 samples collected per cow between 3 and 16 days in milk. Blood BHBA concentrations have already been measured on these samples; serum NEFA concentrations will be measured through the New York State Animal Health Diagnostic Center. Data regarding development of a displaced abomasum, removal from herd, conception to first service, and daily milk production have been standardized and collected from each farm’s computer records using DairyComp 305®. The association of NEFA/BHBA ratio to the downstream outcomes will be evaluated through a combination of contingency tables and modeling techniques (e.g. Poisson regression). The second aim will be completed using all cows from Aim 1; serum FGF21 concentrations will be determined using a sandwich ELISA in the lab of Yves Boisclair in the Department of Animal Science at Cornell University.The third aim will be achieved by determining sire profiles of the cows in Aim 1 through each farm’s computer records. Sire level risk factors will then be evaluated by a combination of contingency tables and modeling techniques (e.g. Poisson regression) to assess the risk of heredity for development of postpartum ketosis, elevated NEFA concentrations, and FGF21. This study will provide an excellent training experience for veterinarians seeking research training as well as potentially identify a key factor for which the dairy industry could select for the cows best able to adapt to high milk production.