Effect of the ovulatory follicle diameter and progesterone concentration on the pregnancy rate of fixed-time inseminated lactating beef cows

Abstract

-The objective of this study was to evaluate the influence of the ovulatory follicle diameter on the reproductive performance of lactating beef cows subjected to low progesterone fixed-time artificial insemination (FTAI) protocols. Ninety-three lactating beef cows (60-80 days postpartum) at random stages of estrous cycle were given a luteolytic dose of prostaglandin F2α (500 μg cloprostenol; PGF) twice, 11 d apart. Ten days after the second PGF treatment, cows were given 1.5 mg of estradiol benzoate im and a progesterone-releasing intravaginal device (Cue-Mate) with a single pod containing 0.78 g progesterone (Day 0). Cows received another luteolytic dose of PGF on Day 0. On Day 8, the Cue-Mate was removed.Fifty-four to 56 hours later, cows received 12.5 mg of porcine LH (pLH) i.m. and were concurrently artificially inseminated.Ultrasound examinations of the ovaries were performed on Days 10 and 17 to evaluate the diameter of ovulatory follicle and corpus luteum, respectively. Cows which presented ovulatory follicle > 19 mm resulted in larger corpus luteum than cows that had ovulatory follicle <15 mm in diameter. However, cows with ovulatory follicle between 13-15 mm had higher pregnancy rate than other categories of ovulatory follicle. Although larger ovulatory follicles result in larger corpus luteum and consequently higher progesterone production, the optimal size of ovulatory follicles (13-15 mm) may result in positive benefits on pregnancy rate for cows subjected to FTAI with low progesterone concentration protocols.

Efficacy of repeatedly used CIDR device in cattle reproduction: a metaanalysisreview of progesterone concentration and conception rate

“…During low P 4 concentrations, LH pulsatility is enhanced, resulting in prematuration of oocytes. These oocytes can be fertilized but do not have development competence (22)(23)(24).…”

Evaluating Programmed Artificial Insemination for Cattle Production

“…The productivity of the cattle is largely identified by whether the cattle shows regular and normal estrous cycles or not. There are many influential factors for the reproductivity of the cattle farming which are already elaborated by various researchers and veterinarian [6], [7], [8], [9], [10], [11], [12], [13]. Understanding the estrous cycle is the first step for the applicability of pAI and many measurement indices are responsible for it [14], [15], [16].…”

Japanese Dairy Cattle Productivity Analysis using Bayesian Network Model (BNM)

“…The reproductive function of a cow or heifer is characterized by whether she displays normal estrous cycles or not. Many factors have potential influences on the presence or absence of estrous cycle of heifers and researchers already focused on it elaborately [5,6,7,8,9,10,11,12]. Body condition Score (BCS), Days after childbirth and or Postpartum Interval(PPI), parity number, ovarian characteristics, uterine blood flow, progesterone level(P4), climate and nutritional factors are mostly discovered influential factors in this arena [13,14,15,16].…”