Clinical evaluations of a new prostaglandin analog in pigs: 1. Control of parturition and of the MMA-syndrome.
In two field trials, the parturition inducing and MMA preventing effects of the prostaglandin F(2alpha) analog (PGFA), K 11941, were explored. In trial 1, 100 sows were treated with 2 mg and 30 with 3 mg of K 11941 i.m. on day 112 of gestation; 125 sows treated on day 112 with 175 mcg cloprostenol (Planate, ICI) served as positive controls, and 248 sows treated with saline on day 112 of gestation were used as negative controls. Both PGF analogs were equally effective in inducing early parturiton: 84.6% and 83.2% of the sows had farrowed between 20 and 30 hours after treatment. Both treatments reduced stillbirth rate and piglet losses during the first 10 days of life, and lowered the incidence of MMA significantly (6.2 and 5.6% vs 27.3 and 24.2%; p<.001). In a second trial, parturitions were induced in four groups of 60 sows each with 2 mg K 11941, housed in farms with either a chronic high incidence of MMA (A: 45 to 65% or only a seasonal rise in MMA during summer (B: 10 to 50%). Groups were treated either in April/May or August/September; 240 salinetreated, control sows were used. K 11941-induced parturition reduced MMA incidence in farm A during both seasons and prevented the summer rise in farm B (p<.01). Fertility after weaning was impaired in herds with an increased incidence of MMA.
The induction and synchronization of parturition in sows treated with I.C.I. 79,939, an analogue of prostaglandin F2x
Summary I.C.I. 79,939, a potent analogue of prostaglandin F2a, was used to induce and synchronize parturition in seven gilts and three sows. A total dose of up to 750 μg injected intra-muscularly during a treatment period of about 24 h on days 109–111 of gestation induced parturition approximately 26 h after the start of treatment. The length of gestation, which was 114 ± 0·2 days in 147 normal untreated pigs, was significantly reduced to 111 ± 0·2 days (P < 0·01) in ten pigs in the same herd treated with I.C.I. 79,939. In this trial, no side-effects were detected, the average birth and 3-week weights of piglets were within the normal range, and sows usually returned to normal oestrus within a week after weaning.
Plasma estrogen and progesterone levels after mating, and during late pregnancy and postpartum in cows.
Peripheral blood plasma was analyzed for total estrogen and progesterone concentrations concurrently during several reproductive stages of the cow. In trial I, 18 beef heifers were mated and blood was collected every 3 days until they either returned to estrus or until day 39 of pregnancy. In trial II, 10 dairy cows were bled daily from 7–14 days prior to parturition, then on a twice a week basis for 60 days postpartum. Estrogen and progesterone concentrations were determined by radio assay. In mated cows that returned to estrus, the mean estrogen level was below 7 pg/ml on day 3, 6, 12 and 15. It increased to a minor peak on day 9 (13 pg/ml) and to a major peak just before estrus (25 pg/ ml). In pregnant cows, it was low (<5 pg/ml) from day 3 until 39. Plasma progesterone increased from 1.2 ng/ml on day 3 to levels of 8.2 ng/ml and 9.9 ng/ml on day 12, in the two groups, respectively. After day 12, the progesterone level declined in the nonpregnant cows and increased to 13.9 ng/ml in the pregnant cows. D...