• Basic Information
• Additional Info

Basic Information

• Project No. and Title: W2112 : Reproductive Performance in Domestic Ruminants
• Period Covered: 10/01/2014 to 09/30/2015
• Date of Report: 09/29/2016
• Annual Meeting Dates: 05/23/2016 to 05/24/2016

Participants

1. Kristen Govoni University of Connecticut 2. Milan Shipka University of Alaska 3. Andrea Cupp University of Nebraska 4. Tom Geary USDA-ARS Fort Keogh, Montana 5. Caleb Lemley Mississippi State University 6. Randy L. Bogan University of Arizona 7. Brenda Alexander University of Wyoming 8. Phil Cardoso University of Illinois 9. Kim Vonnahme North Dakota State University 10. James Berardinelli Montana State University 11. Ky G. Pohler University of Tennessee 12. John Stevens Utah State University 13. Ron Randel Texas A&M 14. Thomas Hansen Colorado State University

Accomplishments

Impacts

1. • A single i.m. injection of 400 mg medroxy progesterone acetate (Depo-Provera) was sufficient to reduce aggressive and rut related behavior, maintain food consumption and significantly reduce rut related weight loss, without completely blocking semen and sperm related fertility characteristics in reindeer bulls. The Depo-Provera treated bulls behaved as functional castrates. • Handling bulls treated with Depo-Provera during the lead up to the rut period allowed for maintenance of tractable animals throughout the rut period thereby providing safety improvement and risk reduction for humans responsible for animal care and for pen mates of rutting bulls. • Rutting reindeer bulls are notoriously known for destructing gate, fences, feeders and any other equipment within reach because of relentless aggressive activities toward inanimate objects. Treatment of reindeer bulls with Depo-Provera prior to the rut period causes bulls behaved as functional castrates resulting less facility and repair costs associated with maintaining reindeer bulls during the rut.
2. • Chronic elevation of norepinephrine, associated with placental insufficiency-induced IUGR, programs islet processes involved with metabolism of lipids, proteolysis, response to nutrient, and proliferation. • High throughput RNA sequencing identified pathways that describe mechanisms consistent with a predisposition for efficient substrate metabolism and fatty acid re-esterification in IUGR adipose tissue.
3. • Rumen-protected methionine added to the diet of Holstein cows improves the survival rate of preimplantation embryos. • Cows fed methionine have more lipid droplets inside the preimplantation embryo, which could be used as energy by the embryos.
4. • Exit velocity during estrous synchronization was lower for pregnant compared with non-pregnant beef cows. • Cows exiting the chute slower at CIDR removal tended to exhibit higher AI pregnancy rates compared with cows exiting faster. • There are breed differences in exit velocity.
5. • Lower plasma cortisol concentrations at CIDR insertion resulted in higher pregnancy rates. • There may be breed differences in plasma cortisol concentrations in beef cows synchronized for AI.
6. • Investigation of the role of oocyte-derived follistatin in early embryogenesis supports the utility of follistatin treatment as a potential tool to increase efficiency of in vitro embryo production and embryo quality and provides a viable platform to aid studies of the contribution of poor oocyte quality to infertility in cattle in a production setting.
7. • Interferon-tau decreased activity of CYP1A and CYP2C in a bovine endometrial cell line. These enzymes are involved in estradiol, progesterone and/or arachidonic acid metabolism, which could alter early signals for maintenance of pregnancy.
8. • On day 16 post-insemination activity of UGT was decreased in CL from pregnant cattle versus non-pregnancy cattle. This may increase local steroid and or eicosanoid bioavailability during pregnancy.
9. • The time spent waiting for the attainment of puberty is one of the greatest barriers to increased reproductive performance in cattle. In bulls, we demonstrated that a high-energy diet from 8 to 33 weeks of age causes noteworthy changes such as increased testicular growth and increased LH and testosterone secretion. However, in this experiment, these physiological changes failed to translate into hastened puberty or increased sperm production. However, these data warrant additional studies to understand how to best utilize prepubertal diets in cattle, as well as to understand other ways to impact the attainment of puberty.
10. • Expression of sexual behavior is essential for successful reproduction especially in domestic species in which assisted reproductive technologies are precluded due to anatomical limitations. Approximately 20% of rams express limited sexual interest potentially slowing genetic progress for the flock. These studies have determined low sexually performing rams have an intact and functional olfactory system that appears to equally identify and respond to sexually evocative odors. Differences in activity at the bed nucleus of the stria terminalis and preoptic area of the hypothalamus suggest these olfactory signals are not being translated to a sexually explicit signal. Deficits in the reward pathway in sexually inactive rams may limit reinforcement of sexual activity and ultimately limit sexual interest.
11. • We have made significant strides in understanding the specific implications of maternal obesity on offspring health, growth efficiency, glucose-insulin dynamics and reproductive function. Results from these studies shed light on the specific physiological mechanisms involved, as well as lead us to management practices to optimize offspring health and production efficiency. These studies provide strong evidence that the optimization of maternal nutrition and the associated uterine environment will contribute to the birth of healthy, growth-efficient offspring, which is vital to livestock production efficiency. Further, recent data demonstrate that the negative metabolic effects of maternal obesity are observed in their children and grandchildren.
12. • The helix-loop-helix transcription factors encoded by the Tcf3 and Tcf12 genes are functionally required for female fertility. Conditional deletion of Tcf3 and Tcf12 results in disruption of LH production by the pituitary. Here, both the alpha and beta subunits of LH are transcriptionally blunted in Tcf3/12 knockout mice. It has now been established that Tcf3 and Tcf12 function in the uterus to regulate the expression of hemoglobin biosynthetic genes.
13. • Characterization of the bovine and ovine Y chromosome provides important comparative mapping information for studying Y chromosome biology and evolution, and resources for developing male-specific genetic markers that will allow us to identify high and low fertility bulls in a sire selection program. Our results further confirmed that the PRAME/PRAMEY gene family is essential for spermiogenesis and male fertility, which provide insights into the molecular mechanism of spermatogenesis.
14. • Optimized in vitro fertilization conditions for sex-sorted semen results in improved in vitro embryonic development.• Sperm motility enhancers improve in vitro fertilization by sex-semen. • Shortening the oocyte-sperm co-incubation time during IVF improves in vitro embryo development.
15. • Pregnancy/embryonic viability detection is possible with PAGs as early as day 24 of gestation; however, embryonic mortality between day 24-31 of gestation may be problematic for earlier pregnancy detection. • Deciphering how uterine gland formation can be manipulated early during postnatal life can have consequences on lifelong reproductive potential in cattle and other mammals. • Identifying the embryonic and extraembryonic alternations that occur when conceptuses are exposed to adverse maternal environments may lead to the discovery of ways to prevent these alterations from occurring, thus improving gestational and postnatal health of offspring. • Examining the complexity of trophoblast responses to multiple uterine and conceptus signals will enable us to obtain a more complete picture of how the uterus mediates early placental development. This will provide new insights that may be used to develop schemes for improving pregnancy retention in cattle. • The linkage between circulating PAG concentrations and productivity parameters will help us to foresee when problems with reproductive performance may occur so they may be corrected before cattle are bred.
16. • Increases in circulating concentrations of PAG early in gestation are predictive of the developing embryo’s success as well as indicative of the fertility status of the dam. Also, maternal PAG concentrations appear to be embryo rather than dam dependent since they were not repeatable over successive pregnancies within dam. • On day 17 and 24 of gestation circulating microRNA profiles differ in abundance between pregnant, non-pregnant and control cows.
17. • On day 16 post-insemination activity of UGT was decreased in CL from pregnant cattle versus non-pregnancy cattle. This may increase local steroid and or eicosanoid bioavailability during pregnancy. • Overfed ewes exhibited an increase in placental UGT activity which is congruent with decreased concentrations of steroids during overfeeding. • Binuclear cells in the ovine placenta may be influenced by dietary change from mid to late gestation. However, it appears that the number of BNCs in the ovine placenta are not impacted by late gestation dietary levels of protein, or if restriction remains throughout mid to late gestation. • While maternal diet does not impact BNC numbers in the beef cow, day of pregnancy does appear to alter BNC numbers.
18. • Interferon-tau decreased activity of CYP1A and CYP2C in a bovine endometrial cell line. These enzymes are involved in estradiol, progesterone and/or arachidonic acid metabolism, which could alter early signals for maintenance of pregnancy.

Publications