Effect of the previously gravid uterine horn and postpartum interval on follicular diameter and conception rate in beef cows treated with estradiol benzoate and progesterone.

Abstract

An experiment was performed to evaluate the effect of the side of ovulation with respect to the previously gravid uterine horn on fertility of cows inseminated at one of two periods postpartum. All cows were treated with an intravaginal progesterone insert for 7 d and received estradiol benzoate (2 mg, i.m.) at the time of device insertion, prostaglandin F2alpha (25 mg, i.m.) at the time of device removal, and estradiol benzoate (1 mg, i.m.) 30 h after device removal. All cows were inseminated 28 to 30 h after the second treatment with estradiol benzoate, regardless of observed estrus. Cows treated in Period 1 received inserts at 16 to 20 d postpartum and were inseminated at 25 to 29 d postpartum. Cows treated in Period 2 received inserts at 26 to 30 d postpartum and were inseminated at 35 to 39 d postpartum. Diameter of the largest follicle at insert removal was greater in cows treated in Period 2 (10.1 +/- 0.3; mm +/- SEM) than in cows treated in Period 1 (9.1 +/- 0.3; P < .05). Diameter did not differ with the side of ovulation in respect to the previously gravid uterine horn. Diameter was greater in cows 5 to 9 (10.3 +/- 0.3) than in cows 3 to 4 (9.0 +/- 0.3) or 10 to 13 (9.4 +/- 0.6) yr of age (P < .01). The proportion of cows that ovulated from the ovary contralateral to the previously gravid uterine horn was greater (P < .05) than of those that ovulated from the ipsilateral ovary, and the incidence of ovulation was reduced in cows 3 to 4 yr of age (P < .01). Conception rate tended to be greater for ovulation from the ipsilateral compared with the contralateral ovary, relative to the previously gravid uterine horn (P < .10) and for ovulation from the right than the left ovary (P < .06). Conception rate was less if cows ovulated a follicle that was < 9 mm than a follicle > or = 9 mm in diameter at insert removal (P < .01) and was greater in cows inseminated in June than in April or May (P < .05). In conclusion, in cows in which estrus was synchronized at 25 to 39 d postpartum, ovulation from either the ovary ipsilateral to the previously gravid uterine horn, or the right ovary, tended to increase fertility.

Evaluation of ovulation rate and ovarian phenotype in puberal heifers from a cattle population selected for increased ovulation rate1,2

“…Interestingly, there was a slight negative correlation between ovulation rates of an ovary from one cycle to the next because ovulations tended to occur on the ovary opposite of the previous ovulation site(s). This effect is well-documented with the CL of pregnancy (Saiduddin et al, 1967;Nation et al, 1999;Bridges et al, 2000), and one hypothesis is that local factors involved in the regression of the CL of pregnancy may inhibit development of a dominant follicle (Saiduddin et al, 1967;Spicer et al, 1986;Nation et al, 1999). Therefore, regression of the previous CL in the consecutive cycles examined in the present study may influence the location of the dominant follicle in a subsequent cycle.…”

Effect of a CIDR insert and flunixin meglumine, administered at the time of embryo transfer, on pregnancy rate and resynchronization of estrus in beef cattle

“…In a recent review of the literature, the postpartum anestrus period in suckled beef cows was reported to be from 29 to 67 d (Yavas and Walton, 2000). The first estrous cycle following the post-partum anestrus period can be short and is associated reduced fertility (Bridges et al, 2000;Yavas and Walton, 2000). Moreover, the fertility of post-partum cows is increased in cows that have had one or more estrous cycles before breeding (Rhodes et al, 2003).…”

Relationship between the side of pregnancy and side of subsequent ovarian activity during the early postpartum period in lactating dairy cows

“…Several studies indicate that the presence of a large follicle in the ovary ipsilateral to the side of previous pregnancy improves reproductive performance [ 15 , 16 , 17 ]. In the present study, the number of cows that experienced ipsilateral ovulation was too small to analyze the effect of the presence of a large follicle in the ipsilateral ovary on fertility.…”

“…The presence of a follicle > 8-mm in diameter in the ipsilateral ovary is associated with a shorter calving to conception interval [ 15 ]. Moreover, ovulation in the ipsilateral ovary prior to insemination is associated with an improved conception rate [ 16 ]. These studies were conducted with the hypothesis that an increase in estradiol secretion from the dominant follicle (DF) in the ipsilateral ovary locally enhances uterine involution; however, this hypothesis has not yet been accepted [ 17 ].…”

“…These studies were conducted with the hypothesis that an increase in estradiol secretion from the dominant follicle (DF) in the ipsilateral ovary locally enhances uterine involution; however, this hypothesis has not yet been accepted [ 17 ]. Very limited information on the influence of postpartum ovarian activity on the reproductive traits of cows is available [ 12 , 15 , 16 ]. There are currently no studies on the relationship between postpartum ovarian activity imbalance and dairy cow productivity traits, including body condition and milk composition.…”