Recipient Organization
UNIVERSITY OF PUERTO RICO AT MAYAGUEZ
P. O. BOX 9000
MAYAGUEZ,PR 00681
Performing Department
Animal Science
Non Technical Summary
Elevated temperature and humidity environments negatively impact dairy cattle milk production and reproductive efficiency, thus decreasing farm products and economic viability. It has been identified that cattle carrying the slick gene can tolerate higher environmental temperatures but the role of this heat-tolerant genotype on reproductive performance remains unknown. The rationale of this research is that investigation on how heat tolerance ability benefits reproductive performance will provide novel information that can be used to develop strategies to improve dairy cattle performance during heat stress. The significance of this project is that these results may provide preliminary indications of the potential fertility improvements granted with slick hair traits. Results of the proposed work will improve our knowledge related to the effects of slick hair traits on reproduction and whether genetic selection for thermotolerance would diminish economic lossess associated with heat stress. Moreover, this study will be the first to describe the reproductive parameters of slick Holstein compared to non-slick. If we can improve fertility and milk production over the warm and hot ther period, the return can be as high as $300 per cow per year. We will test the potential advantages of the slick cow over the non-slick by analyzing differences in hormone concentrations in serum, collecting immature oocytes and studying the in-vitro development and by comparing differences in estrus detection and pregnancy rates. Results of this research will give us a better understanding of the adaptability of the slick hair Holstein and how this adaptability affects their reproductive ability. These findings will help decrease the economic losses caused by heat stress by contributing to the efforts to produce a farm animal with superior efficiency and productivity.
Animal Health Component
90%
Research Effort Categories
Basic
10%
Applied
90%
Developmental
(N/A)
Goals / Objectives
1. To determine how heat tolerant slick hair Holstein differ in estrus expression rates, ovarian follicle number and hormonal profiles. 2. To determine the difference in oocyte and embryo conditions after developing under heat stress, in vitro maturation, in vitro fertilization and culture. 3. To assess the extent to which the uterine environment, of the slick hair Holstein, protects the early embryo, after embryo transfer under high environmental temperatures.
Project Methods
Blood Collection: Animals will be restrained in a chute and blood will be collected into 10-mL vacutainer tubes via coccygeal venipuncture.-Transrectal Ultrasound: Animals will be restrained in a chute. A palpation glove will be placed on the arm that will enter the rectum. The gloved hand will securely hold the ultrasound probe and be inserted into the rectum. Upon entry, the hand will maneuver the probe to locate the ovaries and follicles.-Transvaginal follicle aspirations: 12 hours from estrus synchronization, oocyte pick up will be performed to collect all developing oocytes. Antral follicles will be collected by ultrasound-guided trans-vaginal follicular aspiration. Aspirates will be collected to assess oocyte number and quality from each animal. These will be used for in vitro culture and embryo development.-Artificial Insemination: Animals will go through estrus synchronization and on day 0 will get artificially inseminated.-Embryo transfer: embryos will be transferred on day 7 post fertilization/estrus.-Data will be analyzed using SAS/Mixed procedures.