Days In Gilts Research Articles

Effects of space allocation and parity on selected physiological and behavioural measures of well-being and reproductive performance in group-housed gestating sows

The aim of this study was to evaluate the effects of parity and space allowance on selected measures indicative of welfare, and on reproductive parameters, in group-housed sows. Selected animals were at first parity or parity three or greater, and were housed with allocated space allowances per pig of 1.4 or 2.8m2. Welfare outcome measures included: injury and lameness scores, plasma cortisol levels, neutrophil:lymphocyte ratios and reproductive performance. These values were recorded at a range of timepoints in the first 24h after mixing, and at 28 days after the mixing event. In general there were few significant effects of space allowance and parity level on the measured outcomes. However, improved reproduction, as evidenced by increased litter size and born alive figures, was seen as a result of increased space allowance in older animals. A contrary response was observed in gilts. Cortisol responses also indicated that there was a rapid habituation to the stress of mixing with levels returning to baseline within 24h. Cortisol levels remained low in older animals but unexpectedly showed a peak at 28 days in gilts. It is postulated that this may have arisen as a result of handling events associated with pregnancy testing.Our results suggest that at least at the chosen stocking densities, parity and space allocation have minimal effect on a number of commonly-used welfare measures.

Post-mortem Examination of Genital Organs from Sows with Reproductive Disturbances in a Sow-pool

Over a period of approx. 15 months, post-mortem (PM) examinations were made on genital organs (34 gilts and 81 sows) from a sow-pool with reproductive disturbances. Anamnestic data on the animals included information about parity number, date of farrowing, dates of weaning, oestrus and service, and cause of culling. At the PM examination, the macroscopic appearance of the ovaries (follicles, corpora lutea, cysts) and uterus (content, endometrium) were studied. Specimens from the endometrium was examined histologically. The most common reason for culling was repeat breeding (67%), in most cases at irregular intervals. The non-productive period averaged 82 days in sows (weaning to slaughter) and 151 days in gilts (from 1st day of mating until slaughter). In 49.6% of the sows no pathological changes were found. Macroscopic examination of the ovaries in 108 animals showed that 69% were cycling normally, 17% were anoestral and 14% had multiple follicular cysts (7 animals were not included due to ovo-testis [1 case], pregnancy [3 cases] and with signs of recent abortion [3 cases]). As judged from the histological examination, 27% of the animals had endometritis, which was classified as mild in 50% of them. Anoestral animals had a higher incidence of endometritis (61%) than animals showing cyclic ovarian activity (19%). This indicates that ovarian inactivity is of importance for the development of endometritis. It was concluded that post-mortem examination of genital organs from animals with reproductive problems is a valuable diagnostic tool. The anamnestic data together with the PM results indicated that management routines (oestrous detection, insemination, grouping at early pregnancy) needed to be changed.

Clinical evaluation of a new prostaglandin analog in pigs: 2. Prophylaxis and therapy of anestrus after weaning in sows and first litter gilts

Alfaprostol 1 1 Alfaprostol (K 11941): 18,19,20-trinor-17-cyclohexyl-13,14 didehydro-PGF 2α-methylester: VETEM S.p.A., Milan, Italy. One ml of the solution contains 1 mg alfaprostol. , a new prostaglandin F 2α (PGF) analog was given in a first trial at two dose levels known to be luteolytic (1 and 2 mg) to 200 sows and first litter gilts at the day of weaning after a 21-day lactation period; 189 controls received saline only. The treatment with alfaprostol shortened the interval to heat (6.0 vs 11.3 days; p<0.01) and increased the percentage of animals coming into heat within 10 days (84.0 vs 65.5%; p<0.01). Fertility to a.i. and litter size at the subsequent parturition were normal. In a second trial, 100 first litter gilts and 100 sows received alfaprostol, 1 or 2 mg, respectively, during July and August when high environmental temperatures tend to increase the rate of anestrus. Again, treatment with alfaprostol shortened effectively the interval to heat (5.9 vs 17.4 days in gilts, p<0.001; 5.6 vs 9.7 days in sows; p<0.01) and greatly increased the number of animals in heat (81 vs 47% in gilts, 83 vs 62% in sows; p<0.001). The effect on the seasonal incidence of clinical anestrus was marked; it was more pronounced in gilts than in sows, expressed by the length of time it took to resume cyclic functions and the lower percentage of animals coming into heat (p<0.001). The effect of alfaprostol was equally well expressed in first litter gilts and sows. In a third trial, 295 anestrous sows and gilts were treated on day 22 after weaning with either 2 mg alfaprostol, or 400 I.U. PMSG+200 I.U. hCG, or saline. Within five days after weaning, 38% of the alfaprostol treated, and 78% and 23% of the animals treated with PMSG/hCG and saline came into heat.

Prostaglandin E (sulproston) is neither luteolytic nor luteotrophic during the estrous cycle in the pig

Prostaglandin E 2 (Sulproston, S) can induce parturotion and luteolysis during late pregnancy in the pig. We now tested whether Sulproston is able to interfere with the duration of the pig's estrous cycle. Sulproston was given i.m. in two injections (0.008 mg/kg each) at 12-hour-intervals to ten gilts day 10, to five gilts day 14 and to five gilts day 16 of the estrous cycle. Blood was collected shortly before and up to 48 hrs after the onset of treatment; further daily blood samples were taken from a day 0 (1st day of standing heat) to the end of the cycle. Sulproston-administration did not shorten or lenghten the duration of the estrous cycle, nor were plasma-progesterone levels altered when compared to controls. In a second study five gilts received the tenfold amount in plasma-progesterone (8.52 ± 2.8 SEM ng, treatment vs. 32.95 ± 1.86 SEM ng/ml, control) occurred on day 11, which had returned by day 16 to the level of controls (19.22 ± 6.28 ng/ml vs. 26.75 ± 2.10 SEM ng/ml, respectively). No alteration in cycle length occurred. Therefore the PGE 2-analogue Sulproston - though luteolytic in late pregnancy - is neither luteolytic nor luteotrophic during the estrous cycle of the pig.

Influence of induced delayed parturition on fetal survival in pigs

Pregnancy was prolonged as long as 23 days in gilts receiving daily oral 6-methyl-17 acetoxy-progesterone (MAP) at a level of 0.27–0.41 mg/kg body weight. These levels of progestin did not effect fetal welfare if administered throughout gestation and did not interfere with normal parturition and live litter size if treatment was terminated at the calculated term date which corresponded with the day of milk let-down. The initiation of milk let-down was not effected by treatment. Severe fetal death occurred in all gilts delivering young naturally during prolonged pregnancy and in gilts whose litters were delivered surgically 12 days or more after milk let-down. Mean live litter size was normal in gilts whose young were delivered surgically within 11 days of milk let-down. Fetal death at 12 days or more of prolonged pregnancy was attributed to placental insufficiency. The reproductive parameters studied were unaffected by the addition of 0.001 to 0.013 mg/kg body weight of diethylstilbestrol (DES) to the progestin treatment or the use of this agent alone.