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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Nutrition, Growth and Physiology » Research » Publications at this Location » Publication #326127
Title: A portion of heifers attaining “early puberty” do not display estrus, are anovulatory and have altered sex hormone binding globulin concentrations

Author
item TENLEY, SARAH - University Of Nebraska
item SUMMERS, ADAM - New Mexico State University
item SPURI-GOMES, RENATA - University Of Nebraska
item ABEDAL-MAJED, MOHAMED - University Of Nebraska
item BERGMAN, JEFF - University Of Nebraska
item KURZ, SCOTT - University Of Nebraska
item WOOD, JENNIFER - University Of Nebraska
item Cushman, Robert - Bob
item CUPP, ANDREA - University Of Nebraska

Submitted to: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2016
Publication Date: 7/16/2016
Citation: Tenley, S., Summers, A., Spuri-Gomes, R., Abedal-Majed, M.A., Bergman, J., Kurz, S., Wood, J., Cushman, R.A., Cupp, A.S. 2016. A portion of heifers attaining “early puberty” do not display estrus, are anovulatory and have altered sex hormone binding globulin concentrations [abstract]. Society for the Study of Reproduction Annual Meeting. Abstract #533 (Scientific Program p. 181). Available: http://www.ssr.org/sites/ssr.org/files/uploads/attachments/node/320/2016_ssr_abstracts.pdf

Interpretive Summary:

Technical Abstract: Cows with excess androstenedione (High A4) in the follicular fluid of dominant follicles attain puberty earlier than their low androstenedione counterparts. Furthermore, High A4 cows are anovulatory (chronic or sporadic) and have lower Sex Hormone Binding Globulin (SHBG) compared to Low A4 ovulatory cows. Thus, our hypothesis was that heifers with earlier puberty are predisposed to altered endocrine profiles, anovulation and reduced conception rates to AI. Blood plasma was collected on N=273 spring born heifers from the years 2012-2014 from weaning (205.2 ±.3 days of age) until just prior to breeding (450.2±.4 days of age). Estrous cycles were synchronized for subsequent AI. Blood plasma was analyzed for progesterone (P4) with concentrations >1 ng/ml and continued cyclicity until date of artificial insemination indicative of puberty attainment. Interestingly, four different P4 profiles were identified in these heifers utilizing SAS: 1) Early Puberty Cycling- pubertal early (244.0±41.2 days of age) and continued cyclicity; 2) Typical Puberty Cycling- pubertal (381.8±12.2 days of age); 3) Start-Stop Cycling- pubertal ( 252.8±20.4 days of age) but discontinued detection of P4; and 4) Not Cycling- no P4 > 1 ng/ml. Utilizing the GLM procedure of SAS it was determined there was no influence of group on AI pregnancy rate (P>.05). Blood plasma was also analyzed for concentrations of SHBG. Heifers with P4 profiles 1&2 have increased concentrations of SHBG prior to puberty when compared with 3&4, which have undetectable concentrations of SHBG until later. Ten heifers (5 Early Puberty Cycling, 1 Typical Puberty Cycling and 4 Start-Stop Cycling) had more intensive blood collection and ultrasound to determine follicular waves and reproductive cyclicity, including estrus and ovulation. Interestingly, heifers with P4 profiles similar to 1&2 had higher progesterone (P<.0001) than their counterparts in 3&4, reproductive cycles where follicles developed, and estrus and ovulation were detected. However, heifers with progesterone profiles similar to those in 3&4 developed follicles; but, estrus and ovulation were not detected and they had altered secretion of SHBG. Therefore, heifers with P4 profiles similar to 3&4 may have difficulty in establishing the hypothalamic-anterior pituitary-gonadal axis and could be a population that will develop chronic or sporadic anovulatory cycles resulting in reduced fertility. This research was funded through USDA grant 2013-67015-20965.