Investigation by meta-analysis of the effect of prostaglandin F2 alpha administered post partum on the reproductive performance of dairy cattle

Abstract

The effects of injecting prostaglandin F2 alpha (PGF) in dairy cattle within 40 days of calving on the rate of pregnancy at first service and on the number of days open were investigated by meta-analysis, by pooling data from numerous independent trials into single analyses. A total of 4052 cows from 24 trials described in 10 papers were included in the analyses of first service pregnancy rate and 2646 cows from 21 trials described in nine papers in the analyses of the number of days open. The analyses were stratified by trial and by the reproductive health of the cows after calving. Treatment with PGF during this early post partum period had no significant effect on the first service pregnancy rate of cows with a normal or abnormal puerperium. An analysis of the data for the number of days open by effect-size methods showed that a significant percentage (54 per cent) of the treated cows had fewer days open than the untreated cows, and that this difference tended to be greater for cows with an abnormal puerperium (59 per cent of treated cows). The weighted average reduction in days open between the treated and control cows was 2.6 days for trials with abnormal cows, and 3.3 days for trials including normal and abnormal cows. However, the calculation of the fail-safe number (F) indicated that it would require only a few studies with a negative response to PGF to negate this finding. Meta-analysis was a useful technique for evaluating the apparently conflicting results of previous studies.

Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3–5 weeks post partum, a randomized, double-blind clinical trial

“…The incidence of post partum uterine infections in clinically healthy cows has been assessed as reducing by self-cure from 92% in the first week to 64% in week 4 and to 25% in week 7 [13]. In a meta-analysis of the prostaglandin effect administered post partum including 4052 cows described in 10 papers, days open were shorter in treated cows as compared to untreated cows (2.6 days) and this difference tended to be greater for cows with an abnormal puerperium (3.3 days) [36]. …”

Randomized clinical trial of antibiotic and prostaglandin treatments for uterine health and reproductive performance in dairy cows

“…A large body of conflicting data exists regarding the benefit of PGF 2α administration for improving uterine health and reproductive performance (Burton and Lean, 1995;LeBlanc, 2008;Galvão et al, 2009). The proposed benefits of PGF 2α would be from induction of estrus in cows having a responsive corpus luteum, causing evacuation of uterine contaminants (Kasimanickam et al, 2005b), or by improvement of uterine defenses by temporarily increasing estrogen and decreasing progesterone concentrations in plasma (Kasimanickam et al, 2005b).…”

Invited review: Use of meta-analysis in animal health and reproduction: Methods and applications

“…In this case, the dose of GnRH and insemination number influenced treatment responses. Burton and Lean (1995) found that the weighted average reduction in days open between treated and control cows was 2.6 d for trials with abnormal cows and 3.3 d for trials including normal and abnormal cows for studies examining the use injections of prostaglandin F 2α after calving.…”