Effectiveness of different farrowing induction protocols in sows using alphaprostol on day 114 of gestation.

Farrowing induction in sows is frequently applied and different protocols were described. Most studies induce farrowing between day 111 and 113 of gestation, but hardly any later during gestation. The aim of this study was to investigate the effects of different induction protocols when applied on d114 of gestation. We randomly assigned 118 sows to four treatment groups: single injection of prostaglandin (1×PG), prostaglandin combined with oxytocin 24 hours later (PG+OT), half the dosage of prostaglandin twice with six hours interval (2×1/2PG), and a control group of which farrowing wasn't induced. All injections were administered intramuscularly in the neck on day 114 of gestation. A significantly higher percentage of sows started farrowing between 22 and 32 hours after induction in the PG+OT-group (68 per cent) and the 2×1/2PG-group (52 per cent) compared to the control group (23 per cent). The 1×PG-group (46 per cent) tended to differ from the control group (P=0.087). More sows from the PG+OT-group were constipated at farrowing (P=0.042). Farrowing duration, birth interval, per cent stillborn piglets, dystocia and other variables were similar between the groups. In the present herd and with continuous farrowing supervision, applying PG+OT or 2×1/2PG on d114 of gestation was efficient to induce onset of farrowing in most of the sows 22-32 hours after induction without considerable negative effects.

Comparison of two intravaginal progesterone releasing devices (PRID-Delta vs CIDR) in dairy cows: blood progesterone profile and field fertility.

Objectives were to compare circulating progesterone (P4) profile and pregnancies per AI (P/AI) of two commercial intravaginal P4 devices (PRID-Delta(®) vs CIDR(®)). In Experiment 1, ovariectomized dairy cows (PRID-Delta, n=6 vs CIDR, n=6) were sampled throughout 7 days to measure circulating P4. In Experiment 2 (PRID-Delta, n=399 vs CIDR, n=375), cows were assigned to treatments, as follows: D0, an intravaginal P4 device containing 1.38g of P4 (CIDR) or 1.55g of P4 (PRID-Delta); D6: 25mg PGF2α (Dinoprost) and P4 devices were removed 24h later. Insemination was performed at 56h after P4 removal. Cows visually detected in estrus between days 18 and 24 after 1st synchronized AI were re-inseminated. PRID-Delta produced greater circulating P4 compared to CIDR, particularly within 4 days after insertion (P<0.01). The logistic regression analysis indicated a tendency for improved P/AI at 1st AI in PRID-Delta cows compared to CIDR (36% vs 31%, P=0.10). More cows were detected in estrus in the following cycle nearly 21d after 1st AI when treated with PRID-Delta (28% vs 16%), but P/AI in the returning-natural estrus breedings did not differ (PRID-Delta=56% vs CIDR=55%; P=0.91). As a result, final cumulative P/AI was greater in cows receiving PRID-Delta (46% vs 37%, P=0.02). These results indicate that PRID-Delta seem to maintain greater circulating P4 levels as compared to CIDR in non-lactating dairy cows. This might explain potential benefits in fertility of dairy cows found in Experiment 2. Underlying physiological consequence of greater circulating P4 during synchronization programs in lactating cows in terms of oocyte quality and other reproductive structures warrants further investigation.