Fertilization Failure and Embryonic Mortality in Parous and Nonparous Beef Cattle1

Maurer, R. R.; Chenault, J.R.

doi:10.2527/jas1983.5651186x

Cited by 98 publications

(48 citation statements)

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“…This is in agreement with a report that low-fertility cows that had failed to produce a calf in either 1 or 2 previous seasons did not demonstrate a failure in ovulation (Warnick and Hansen, 2010). Because conception rates are relatively high in beef cows (Maurer and Chenault, 1983), this would suggest a greater rate of embryonic loss in repeat breeder cows, as has been reported previously (Maurer and Echternkamp, 1985;Warnick and Hansen, 2010). Thus, oocyte quality may be the connection between decreased follicle numbers and subfertility in heifers and cows.…”

Section: Discussionsupporting

confidence: 81%

Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility12

Cushman

Miles

Rempel

et al. 2013

Journal of Animal Science

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ABSTRACT:A proposed functional polymorphism in the ionotropic glutamate receptor AMPA1 (GRIA1) has been reported to influence antral follicle numbers and fertility in cows. Repeat breeder cows that fail to produce a calf in multiple seasons have been reported to have reduced numbers of small (1 to 3 mm) antral follicles in their ovaries. Therefore, we tested the hypothesis that this GRIA1 polymorphism was affecting antral follicle numbers in repeat breeder cows. Repeat breeder cows (n = 64) and control cows (n = 72) that had always produced a calf were housed in a dry lot and observed twice daily for behavioral estrus. Blood samples were collected, and cows were genotyped for this GRIA1 polymorphism and for a polymorphism in the GnRH receptor (GnRHR) that was proposed to influence age at puberty. On d 3 to 8 after estrus cows were slaughtered, and reproductive organs were collected to determine antral follicle count, ovary size, and uterine horn diameter. Repeat breeder cows were older at first calving than control cows (P = 0.006). The length (P = 0.03) and height (P = 0.02) of the ovary contralateral to the corpus luteum (CL) were greater in control cows than repeat breeder cows. The endometrial diameter in the horn ipsilateral to the CL was greater in the control cows than the repeat breeder cows. Repeat breeder cows had fewer small (1 to 5 mm) antral follicles than control cows (P = 0.003); however, there was no association between GRIA1 genotype and antral follicle number. The GnRHR polymorphism was associated with age at first calving because cows that were homozygous for the C allele had a greater age at first calving than heterozygous cows or cows that were homozygous for the T allele (P = 0.01). In the granulosa cells from small (1 to 5 mm) antral follicles, mRNA abundances of 2 markers of oocyte quality, anti-Müllerian hormone and pentraxin 3, did not differ between fertility groups (P ≥ 0.12). We conclude that this GRIA1 polymorphism exists in beef cows but that it does not influence antral follicle numbers. The association between GnRHR genotype and age at first calving is likely not causal as this polymorphism is not functional. The utility of this polymorphism as a genetic marker for early conception in heifers will require further validation. Screening postpartum cows by ultrasonography to determine antral follicle numbers may aid in making culling decisions.

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Section: Discussionsupporting

confidence: 81%

Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility12

Cushman

Miles

Rempel

et al. 2013

Journal of Animal Science

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“…Beef producers replace 12% to 15% of the cow herd annually, but a lower pregnancy rate for heifers necessitates retention of additional heifers (Maurer and Chenault, 1983). Management of replacement heifers from weaning to breeding is critical to their lifetime productivity.…”

Section: Introductionmentioning

confidence: 99%

Effect of postweaning diet on ovarian development and fertility in replacement beef heifers1

Eborn

Cushman

Echternkamp

2013

Journal of Animal Science

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Programs for developing replacement heifers are designed for heifers to calve at 2 yr of age and to extend their stayability in the herd and minimize feed cost. The experimental objective was to determine whether developing prepubertal heifers on less dietary energy and to a BW of 55% rather than 65% of mature BW at 14 mo of age would compromise ovarian development and reduce fertility. In a 3-yr study, 8-mo-old Angus (n = 60/yr) and composite MARC II (n = 60/yr) heifers were assigned equally by age, BW, and breed to receive either a low (LG) or high (HG) BW gain diet fed to achieve an ADG of either 0.45 or 0.8 kg/d from 8 to 15 mo of age, including the first 21 d of breeding, and then transferred to pasture. At 14 mo, heifers were housed with fertile bulls for 47 d. Estrus was monitored for 21 d. Within 12 h after detection of estrus, ovarian length and height, preovulatory follicle diam., and antral follicle count (AFC) were measured by transrectal ultrasonography. Corpus luteum (CL) volume and plasma progesterone concentration were measured 5 to 15 d after estrus. Data were analyzed by ANOVA with treatment, breed, and year and their 2-way interactions as independent variables. At breeding, HG heifers were heavier than LG heifers (419.9 vs.361.8 ± 7.5 kg; P < 0.01); ADG for the treatment period was 0.79 vs. 0.47 ± 0.04 kg/d (P < 0.01), respectively. In 2010 and 2011, 97.2% of heifers were cyclic by 21 d of breeding. Size of the ovary, preovulatory follicle, CL, and AFC did not differ between HG and LG, but preovulatory follicle diam. and ovarian length were greater (P ≤ 0.05) for MARC II vs. Angus heifers. Progesterone concentrations were less for LG vs. HG heifers (P ≤ 0.02), whereas CL volume was not affected by treatment or breed but was correlated positively with preovulatory follicle size (P < 0.01). Total AFC ranged from 5 to 49 and was correlated positively with ovarian volume but was not associated with fertility. A greater proportion of HG vs.LG heifers conceived within the first 21 d of the breeding period (64.4% vs. 49.2% ± 3.8%, respectively; P < 0.01), but overall pregnancy rate was not affected by treatment (83.0% vs. 77.7% ± 3.1%, respectively; P > 0.10). Pregnancy rate was 10% less (P < 0.01) for Angus vs. MARC II heifers. Developing beef heifers at a lesser ADG to a lighter BW (55% vs. 64% of mature BW) at breeding did not influence postweaning ovarian development or AFC or compromise pregnancy rate during the 47-d breeding period.

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“…Clinical pregnancy was about for 40% for both repeat breeders and controls. Maurer and Chennault [12] reported that 67% of embryonic death in cattle occurred within 8 days after fertilization. We attemped ET to reduce the early embryonic losses and within 6 days after ET (equivalent to 13 days after estrus) detected the presence of EPF.…”

Section: Discussionmentioning

confidence: 99%

EPF as a Marker for Early Embryonic Losses in Repeat Breeders.

Yamazaki

Kawahata

Goto

et al. 1995

Journal of Reproduction and Development

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Fertilization Failure and Embryonic Mortality in Parous and Nonparous Beef Cattle1

Cited by 98 publications

References 0 publications

Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility12

Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility12

Effect of postweaning diet on ovarian development and fertility in replacement beef heifers1

EPF as a Marker for Early Embryonic Losses in Repeat Breeders.

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