Farrowing induction with a combination of prostaglandin F(2alpha) and a peripherally acting alpha(2)--adrenergic agonist AGN 190851 and a combination of prostaglandin F(2alpha) and oxytocin

We studied the effect of prostaglandin (PG) F(2alpha)-AGN 190851 on farrowing induction and compared it with that of PGF(2alpha)-oxytocin. Eighty crossbred, multiparous sows were randomly assigned to the following 4 treatment groups of 20 sows each: 1) control, saline-saline; 2) PGF(2alpha) (10 mg/sow)-oxytocin (30 IU/sow); 3) PGF(2alpha) (10 mg/sow)-AGN 190851 (0.06 mg/kg); and 4) PGF(2alpha) (10 mg/sow)-AGN 190851 (0.1 mg/kg). Either PGF(2alpha) or saline was administered intramuscularly on Day 111 of gestation at 11:30 h; AGN 190851, oxytocin or saline was administered intramuscularly 20 h after the first injection. The PGF(2alpha)-AGN 190851 (0.1 mg/kg) treated sows had the shortest mean farrowing interval (2.1 +/- 1.6 h, mean +/- SD) compared with the remaining treatment groups (control: 67.1 +/- 26.2 h; PGF(2alpha)-oxytocin: 5.6 +/- 6.7 h; PGF(2alpha)-AGN 190851 [0.06 mg/kg]: 3.0 +/- 2.8 h). Duration of farrowing, litter size, litter weight and interval from weaning to first estrus in sows were not significantly changed by these treatments. The PGF(2alpha)-oxytocin group had a significantly higher stillbirth rate than the control group, whereas the PGF(2alpha)-AGN 190851 (0.1 mg/kg) group had the lowest number of pigs born dead and stillbirth rate among the 4 treatment groups. These results suggested that the PGF(2alpha)-AGN 190851 combination can be used as an alternative method to PGF(2alpha)-oxytocin for synchronizing farrowing.     

Induction of parturition in swine with prostaglandin F(2)alpha, estradiol benzoate and oxytocin

Pregnant sows and gilts were administered either 0, 2.5, 5, 10 or 20 mg prostaglandin F(2)alpha (PGF(2)alpha) intramuscularly on Day 112 or 113 of gestation at 0800 h in an effort to induce parturition. The average interval from PGF(2)alpha injection to farrowing was 55.1 +/- 5.7, 29.4 +/- 3.1, 32.1 +/- 4.6, 27.8 +/- 1.8 and 26.9 +/- 1.1 h for 0, 2.5, 5, 10 and 20 mg, respectively. All PGF(2)alpha treatments increased (P < 0.01) over controls the number of sows farrowing 23 to 33 h after injection. The average gestation length was significantly shorter in treated gilts; however, no detrimental effect on pig performance or pig survivability was observed. A second trial evaluated the effect of a 10-mg dose of PGF(2)alpha on the induction of parturition in sows in order to obtain a majority of sows farrowing within normal working hours (0700 to 1700 h). The interval from injection to farrowing was decreased (P < 0.05) by PGF(2)alpha treatment (66.2 +/- 5.3 vs 28.1 +/- 2.2 h). Fifty-seven percent (P < 0.05) of PGF(2)alpha-treated sows farrowed between 0700 and 1700 h as compared to 13.6% for control sows. A third trial was conducted to examine a sequential treatment of PGF(2)alpha and oxytocin to control the time of parturition more precisely. Sows receiving only 10 mg of PGF(2)alpha farrowed on an average 31.1 +/- 1.4 h after injection. The injection of 40 IU oxytocin 24 to 28 h after PGF(2)alpha decreased (P < 0.05) the interval from PGF(2)alpha to farrowing (28.1 +/- 0.9 h). The addition of oxytocin increased (P < 0.05) the number of sows farrowing within 3 h of injection (33 vs 86% for PGF(2)alpha and PGF(2)alpha + oxytocin treatments, respectively). A fourth trial was designed to determine if the addition of exogenous estradiol benzoate (EB) to a sequential treatment of PGF(2)alpha and oxytocin would improve the predictability and synchronization of the induced parturition. Sows were assigned to receive either saline, 10 mg PGF(2)alpha + 40 IU oxytocin or 10 mg PGF(2)alpha + 5 mg EB + 40 IU oxytocin. The addition of EB reduced (P < 0.01) the variance in the interval from oxytocin to farrowing and added precision to the predicted time of induced parturition.     

Activation of quiescent ovaries by administration of PMSG after LH-RH analogue treatment in heifers

The effect of pregnant mare serum gonadotrophin (PMSG) treatment on activation of quiescent ovaries was examined in heifers. Groups of thirteen, twenty and twelve heifers which showed ovulation within 2 d and corpus luteum (CL) development after injection with a luteinizing hormone releasing hormone analogue (LH-RH-A) were supplementally injected with 500 IU of PMSG (Group I); 500 IU of PMSG and 500 mug of Prostaglandin F(2alpha) analogue (PGF(2alpha)-A; Group II); and 500 mug of PGF(2alpha)-A (Group III) on Day 6 after the injection of 200 mug of LH-RH-A (Day 0), respectively. Estrus appeared in 33.3 to 45.0% of the heifers of the respective groups after the treatment. Ovulation occurred at a significantly (P<0.01) higher rate in Groups I (100%) and II (90.0%) than in Group III (41.7%). The ovarian cyclic activity was initiated in all the heifers that ovulated. Plasma progesterone levels decreased significantly (P<0.05) to about 1 ng/ml on Day 8 and Day 7 in Group I and Groups II and III, respectively. Plasma estradiol-17beta (E(z)) levels increased significantly (P<0.05), reaching a peak on Days 7 to 7.5 in Groups I and II but not in Group III. It is concluded that PMSG treatment stimulates maturation and E(z) secretion of a follicle, thus promoting ovulation and the onset of ovarian cyclic activity.     

The influence of allyl trenbolone (Regumate) on the timing,duration and endocrinology of parturition in sows

A study was undertaken to evaluate the effects of using an oral progestagen for synchronisation of parturition in the sow. Multiparous Landrace X Large White sows were fed 20 mg allyl trenbolone daily from day 110 to 115 of gestation then 15 mg on day 116 (Group R; N = 12); untreated sows of similar background served as controls (Group C; N = 9). Blood samples, taken at 8-h intervals from day 110 of gestation to onset of parturition, then every 4 h until parturition was complete, were assayed for plasma levels of progesterone, unconjugated oestrone, cortisol and prolactin. Duration of farrowing, incidence of stillbirths and individual piglet birth weights were recorded. Five Group R sows farrowed during the period of progestagen administration, while for the remaining 7, the mean interval from last progestagen treatment to emergence of first piglet was 31.6 ±5.5 h. Gestation length, duration of parturition, and mean interval between successive births all were longer in Group R than in Group C (116.5 ± 0.34 compared with 115.0 ± 0.52 days, P < 0.01; 9.73 ± 1.98 compared with 3.08 ± 0.70 h, P < 0.01; and 53.4 ± 10.2 compared with 16.2 ± 2.4 min., P < 0.01, respectively). No significant treatment differences were apparent for litter size at birth, proportion stillborn or piglet birth weights. Profile analysis showed that plasma progesterone levels in Group R were lower (P < 0.05) during the 30 h prefarrowing, suggesting a longer mean interval between functional luteolysis and parturition in these animals. In both Groups plasma levels of unconjugated oestrone rose in the prefarrowing period, the levels being higher (P < 0.05) in Group R Peak oestrone levels occurred at the commencement of, and had declined to low levels by the completion of, farrowing. Cortisol levels exhibited a pattern similar to that of oestrone, although peak levels at parturition were lower in Group R (P < 0.01). Plasma prolactin levels in the 24 h prepartum rose faster and reached higher levels (P < 0.05) in Group C than Group R, but the difference was no longer apparent subsequent to first piglet emergence. It is concluded that the use of this progestagen to delay parturition upset the synchronisation of endocrine events at farrowing, resulting in an increased duration of parturition.     

Control of birth in rats by RU 486, an antiprogesterone compound

Rats, isolated at mating (Day 1 of pregnancy), were submitted to either 8 h (8L:16D, Exp. I) or 14 h (14L:10D, Exp. II) of light daily with lights on from 12:00 h to 20:00 h and from 06:00 to 20:00 h respectively. In Exp. I, a single dose of RU 486 (10 mg in 0.2 ml ethanol) was given cutaneously at 08:00 h (Group A1), 12:00 h (Group B1), 19:00 h (Group C1) on Day 21 and at 08:00 h (Group D1) and 12:00 h (Group E1) on Day 22. In Exp. II, the same dose of RU 486 was given at 08:00 h (Group A2), 12:00 h (Group B2) and 19:00 h (Group C2) on Day 21. The solvent was given once at each of the preceding times to the control groups (T1 and T2) in both experiments. Groups T1 and T2 gave birth at two periods, the first on Day 22, the second on Day 23; the proportion of births during each of these periods depended on the light regimen (66.3% in 8L:16D; 50% in 14L:10D on Day 22). The distribution of births in Groups D1 and E1 treated on Day 22 were similar to their controls (T1). Rats treated on Day 21 (Groups A1, A2, B1, B2, C1, C2) gave birth over single periods on Day 22 after an interval correlated with the time of RU 486 administration. The earlier the treatment was given, the higher was the number of dead young and the lower the weight of live young 1 day after birth. These effects of prematurity did not impair further survival rates or weight at weaning.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a GnRH agonist to prevent the endogenous LH surge and injection of exogenous LH to induce ovulation in heifers superstimulated with FSH: a new model for superovulation

A new protocol for superovulating cattle which allows for control of the timing of ovulation after superstimulation with FSH was developed. The preovulatory LH surge was blocked with the GnRH agonist deslorelin, and ovulation was induced by injection of LH. In Experiment 1, heifers (3-yr-old) were assigned to a control group (Group 1A, n = 4) or a group with deslorelin implants (Group 1B, n = 5). On Day -7, heifers in Group 1A received a progestagen CIDR-B((R))device, while heifers in Group 1B received a CIDR-B((R))device + deslorelin implants. Both groups were superstimulated with twice daily injections of FSH (Folltropin((R))-V): Day 0, 40 mg (80 mg total dose on Day 0); Day 1, 30 mg; Day 2, 20 mg; Day 3, 10 mg. On Day 2, heifers were given PGF (a.m.) and CIDR-B((R)) devices were removed (p.m.). Three heifers in Group 1A had a LH surge and ovulated, whereas neither of these events occurred in Group 1B (with deslorelin implants) heifers. In Experiment 2, heifers (3-yr-old) were assigned to 1 of 4 equal groups (n = 6). On Day -7, heifers in Group 2A received a norgestomet implant, while heifers in Groups 2B, 2C and 2D received norgestomet + deslorelin implants. Heifers were superstimulated with FSH starting on Day 0 as in Experiment 1. On Day 2, heifers were given PGF (a.m.) and norgestomet implants were removed (p.m.). Heifers in Groups 2B to 2D were given 25 mg LH (Lutropin((R))): Group 2B, Day 4 (a.m.); Group 2C, Day 4 (p.m.); Group 2D, Day 5 (a.m.). Heifers in Group 2A were inseminated at estrus and 12 and 24 h later, while heifers in Groups 2B to 2D were inseminated at the time of respective LH injection and 12 and 24 h later. Injection of LH induced ovulation in heifers in Groups 2B to 2D. Heifers in Group 2C had similar total ova and embryos (15.2 +/- 1.4) as heifers in Group 2A (11.0 +/- 2.8) but greater (P < 0.05) numbers than heifers in Group 2B (7.0 +/- 2.3) and Group 2D (6.3 +/- 2.0). The number of transferable embryos was similar for heifers in Group 2A (5.8 +/- 1.8) and Group 2C (7.3 +/- 2.1) but lower (P < 0.05) for heifers in Group 2B (1.2 +/- 0.8) and Group 2D (1.3 +/- 1.0). The new GnRH agonist-LH protocol does not require observation of estrus, and induces ovulation in superstimulated heifers that would not have an endogenous LH surge.     

Effects of bromocriptine and perphenazine on prolactin and progesterone concentrations in pregnant pony mares during late gestation

Pregnant pony mares in Group A (n = 4) received i.m. injections at 07:00 and 17:00 h of 0.8 mg bromocriptine/kg body weight 0.75 per day beginning on Day 295 of gestation and continuing until parturition. Group B (n = 4) was treated similarly, but perphenazine was administered orally at 0.375 mg/kg body weight twice a day beginning on Day 305 of gestation and continuing until parturition. Mares in Group C (n = 3) received i.m. injections of saline. Mean plasma prolactin and progesterone concentrations were greater (P less than 0.05) for mares in Group C than in Groups A and B from 295 to 309 days of gestation. From 305 days of gestation, plasma prolactin and progesterone concentrations were greater (P less than 0.05) in Group B and C than in Group A mares. Progesterone and prolactin concentrations increased over this period for Group B and Group C mares, but remained constant in Group A mares. From 10 days pre partum through foaling, mares in Group A had lower progesterone (P less than 0.05) and prolactin (P less than 0.01) concentrations than Group B and C mares. All mares in Group A were agalactic at foaling, while all mares in Groups B and C had normal milk secretion. Gestation was longer (P less than 0.05) in Group A than in Group C mares. In Group A, 2 mares retained the placenta for greater than 3 h, 3 mares had dystocia and all 4 mares had thickened, haemorrhagic placentae.(ABSTRACT TRUNCATED AT 250 WORDS)     

Control of parturition in the sow using progesterone and prostaglandin

The effect of progesterone and prostaglandin administration on the timing of farrowing was studied in three groups of 25 sows each. Progesterone treatment (100 mg/day) on days 112, 113 and 114 of gestation (group I) significantly prolonged the gestation length to 116.4 +/- 0.4 (mean +/- s.e.) days compared to the control sows (group III; 115.5 +/- 0.2; P less than 0.05). Administration of prostaglandin (200 micrograms Cloprostanol intramuscularly) on day 115 of gestation following progesterone treatment (group II) resulted in a gestation length of 116.0 +/- 0.1 days, with the sows farrowing 25.4 +/- 1.0 h after the prostaglandin injection. 80% of the sows farrowed between 0800 and 1700 h of day 116 of gestation. Plasma progesterone levels were maintained by the exogenous progesterone during treatment. At farrowing, higher levels of progesterone were observed in groups I and II compared to controls. Prostaglandin treatment did not significantly alter withdrawal of progesterone in progesterone treated sows, suggesting that the actions of exogenous prostaglandin is primarily on the myometrium and the cervix. Hormonal treatment in late pregnancy did not have any adverse effects on piglet viability and growth rate, or subsequent reproductive performances of sows. Lactation was initiated normally, and the concentrations of lactose, protein, fat, IgG, Na+, Ca2+ and K+ in colostrum and milk were similar in all groups during the first 5 days of lactation.     

Progesterone levels and litter performance of sows following postpartum administration of prostaglandin F(2alpha)

A total of 101 sows was used to examine postpartum progesterone levels and litter performance following administration of 15 mg prostaglandins F(2alpha) (PGF(2alpha) n = 48) given within 12 h after farrowing. Daily blood samples and rectal temperatures were taken from all sows during the first 3 d post partum. Plasma progesterone (P(4)) concentrations were determined by radioimmunoassay (RIA). Regardless of treatment, plasma P(4) levels for all sows decreased in a similar fashion over the 3 d sampled. Mean (+/- SEM) P(4) on Day 2 (0.55 +/- 0.06 ng/ml) and Day 3 (0.38 +/- 0.04 ng/ml) were lower (P<0.01) than on Day 1 (0.98 +/- 0.08 ng/ml). Rectal temperature did not differ between PGF(2alpha) treated and nontreated sows nor was it different over the days measured. Litter characteristics, including survival rates on Day 7 and at weaning, and body weight on Days 3 and 35, were not affected by treatment. It was concluded that PGF(2alpha) administration to sows within 12 h post farrowing had no affect on the rate of luteal regression, as determined by P(4) concentration, nor on subsequent litter performance.     

Sow environment during gestation: part I. Influence on maternal physiology and lacteal secretions in relation with neonatal survival

In pig husbandry, pregnant females are often exposed to stressful conditions, and their outcomes on maternal and offspring health have not been well evaluated. The present study aimed at testing whether improving the welfare of gestating sows could be associated with a better maternal health during gestation, changes in the composition of lacteal secretions and improvement in piglet survival. Two contrasted group-housing systems for gestating sows were used, that is, a French conventional system on slatted floor (C, 49 sows) and an enriched system using larger pens on deep straw (E, 57 sows). On the 105^th days of gestation (DG105), sows were transferred into identical farrowing crates on slatted floor. Saliva was collected from all sows on DG35, DG105 and DG107. Blood samples were collected on DG105 from all sows and on the 1^st day of lactation (DL1) from a subset of them (C, n=18; E, n=19). Colostrum and milk samples were collected from this subset of sows at farrowing (DL0) and DL4. Saliva concentration of cortisol was greater in C than in E sows at DG35 and DG105, and dropped to concentrations comparable to E sows after transfer into farrowing crates (DG107). On DG105, plasma concentrations of haptoglobin, immunoglobulins G (IgG) and A (IgA), blood lymphocyte counts and plasma antioxidant potential did not differ between groups (P > 0.10), whereas blood granulocyte count, and plasma hydroperoxide concentration were lower in E than in C sows (P < 0.05). Concentrations of IgG and IgA in colostrum and milk did not differ between the two groups. The number of cells did not differ in colostrum but was greater in milk from E than C sows (P < 0.05). Pre-weaning mortality rates were lower in E than C piglets (16.7% v. 25.8%, P < 0.001), and especially between 12 and 72 h postpartum (P < 0.001). Plasma concentration of IgG was similar in E and C piglets on DL4. In conclusion, differences in salivary cortisol, blood granulocyte count and oxidative stress markers between groups suggested improved welfare and reduced immune solicitation during late gestation in sows of the E compared with the C system. However, the better survival observed for neonates in the E environment could not be explained by variations in colostrum composition.     

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.     

Behavioral and endocrine responses of sows to prostaglandin F2 alpha and cloprostenol

Behavioral and endocrine changes in the sow following injection with prostaglandin F2 alpha (PGF2 alpha) or its analogue, cloprostenol (CLO), were monitored to identify endocrine correlates of prepartum activity (nest-building). On Day 112 postcoitum, within 15 min after injection with 10 mg PGF2 alpha, sows offered straw in pens engaged in intense prepartum activity, but few behavioral changes occurred during the first 2 h following administration of 175 micrograms CLO. The temporal pattern of prepartum activity, however, was affected by both prostaglandins. In control sows, most prepartum activity came during Hours 16-0 before delivery of first piglet (delivery). After CLO, sows engaged in nest-building more during Hours 32-17 and less during Hours 16-0. In another experiment, sows in farrowing crates were injected with saline, 175 micrograms CLO, or 10 mg PGF2 alpha on Day 112 and blood was collected 0, 15, 30, 60, and 90 min later. Another sample was collected when spontaneous prepartum activity was first observed. For approximately 90 min after PGF2 alpha treatment, sows rooted, pawed, and bit and rubbed faces on crate bars; after saline and CLO, this behavior was rarely observed. After prostaglandin treatment, plasma progesterone tended to decline, a 10-fold rise in relaxin came within 15 min, but estrone did not change. Plasma prolactin rose 10-fold within 30 min after PGF2 alpha treatment, and rose more gradually after CLO treatment. When sows exhibited spontaneous prepartum activity (approximately 7 h before delivery), endocrine status was characterized by low progesterone, high estrone:progesterone ratio, and high prolactin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plane of nutrition during gestation affects reproductive performance and retention rate of hyperprolific sows under commercial conditions

Defining a maternal plane of nutrition during gestation is pivotal for improving sow productivity and the cost-effectiveness of feeding. The benefits of increasing the amount of feed during late gestation have been controversial. The objective of this study was to investigate the effects of different planes of nutrition during gestation on reproductive performance of hyperprolific sows and pre-weaning litter performance. One hundred and thirty-five gestating sows were randomly assigned to one of three planes of nutrition throughout parities three and four (P4), as follows: Req – plane designed to meet requirements of prolific sows (2.3 kg per day from day 1 to 21; 1.8 kg per day from day 22 to 75; 2.3 kg per day from day 76 to farrowing); Bump – plane designed as the Req, with increased feed intake during late gestation (3.0 kg per day from day 91 to farrowing); and Maintenance – plane designed to closely meet maintenance requirements of sows (1.8 kg per day from day 1 to farrowing). All treatments were fed the same gestation diet (2.50 MCal NE/kg; 0.67% SID Lysine; 15.17% CP). Sow biometrical parameters at farrowing and at weaning, and litter characteristics were recorded. Also, blood samples were collected for pre- and post-prandial serum glucose and plasma insulin, as well as triglycerides, calcium, and phosphorus analyses. Culling, stratified by cause, and retention rates were recorded in all treatments for each parity. Over two parities, Bump sows had higher weight gain and, at P4, had a higher number of piglets born alive (P < 0.05). Bump sows lost more weight between the end of gestation and weaning over two parities (P < 0.05). Maintenance sows showed reduced body condition score with a higher percentage of piglets removed throughout lactation (due to inappetence and inability to reach the udder) at P4 (P = 0.03). Pre- and post-prandial glucose levels were higher in Bump sows, as well as post-prandial insulin and phosphorus levels at P4 (P < 0.05). Bump sows also showed increased plasma triglycerides compared to the other treatments (P = 0.03). Retention rate was reduced in Maintenance compared to Bump and Req sows at parity 5 (P = 0.02). Taken together, our results indicate that higher feed intake allowance during late gestation may improve the sow’s nutritional status triggering positive results on litter size of hyperprolific sows (e.g., more than 17 total born). However, body condition score must be carefully evaluated to prevent excessive weight gain during successive parities.     

Synchronization of oestrus and ovulation by short time combined FGA, PGF(2α), GnRH, eCG treatments for natural service or AI fixed-time

Two experiments were conducted in ewes in order to develop an oestrus-ovulation short time synchronization protocol based on combined FGA, PGF(2α), GnRH, eCG treatments, for use in dairy sheep before natural service (Experiment 1) or for fixed-time artificial insemination (Experiment 2), during the breeding season. In Experiment 1 seventy-five non-lactating dairy ewes were subdivided into 5 treatment groups (N=15): (1) Group Fe - control, which received FGA vaginal sponges (14 days)+eCG (Day 14); (2) Group FPe, FGA (5 days)+PGF(2α) (Day 5)+eCG (Day 5); (3) Group PFe, PGF(2α) (Day 0)+FGA (5 days)+eCG (Day 5); (4) Group PFG, PGF(2α) (Day 0)+FGA (5 days)+GnRH (30h after sponge removal, s.r.); (5) Group GPe, GnRH (Day 0)+PGF(2α) (Day 5)+eCG (Day 5). Ewes were checked for oestrus and hand-mated. Time of ovulation was recorded by laparoscopy for 10 animals from each treatment. The percentages of female in oestrus and the interval to oestrus (h after treatment), fertility and prolificacy rate were recorded. There were no treatment differences in the percentage of females in oestrus. The interval to oestrus was earlier in Fe Group and delayed in FPe Group (P<0.01). Ovulation time was earlier in GPe Group compared to FPe Group (P<0.05). Fertility rates were significantly different (P<0.05) between the PFe and the FPeG Groups compared with the PFG Group. No significant differences were observed in prolificacy among the treatments. In Experiment 2, sixty dry ewes were subdivided (N=20) into the following three experimental treatment groups: (1) Group FP, FGA (5 days)+PGF(2α) (Day 5); (2) Group FPG, FGA (5 days)+PGF(2α) (Day 5)+GnRH (30hs.r.); (3) Group FPeG, FGA (5 days)+PGF(2α) (Day 5)+eCG (Day 5)+GnRH (30hs.r.). These were further subdivided into two groups (N=10) corresponding to 52 and 60hs.r. fixed-time insemination. Laparoscopic intrauterine insemination was performed with frozen semen (80×10(6)spermatozoa/dose) and ovulation time was recorded in a subgroup (N=10). GnRH resulted in an earlier ovulation time (P<0.05) in FPG and FPeG Groups (53.0h vs 61.6h). Fertility rate was higher in FPeG treated ewes inseminated at 60hs.r. (60%, 6/10). In FP and FPG Groups fertility rates were higher following insemination at 52hs.r. (50.0 and 40.0%).     

Parturition control in sows with a prostaglandin analogue (alfaprostol)

The objective of this study was to determine the dose of alfaprostol (18, 19, 20-trinor-17-cyclohexyl-13, 14 didehydro-PGF(2)alpha-methylester) and the day of administration most effective in inducing sows to farrow during normal working hours (0700 to 1700). One-hundred forty multiparous crossbred sows, taken from a herd whose mean gestation length was 114.3 days, were assigned to one of five treatment groups: 1) control vehicle-propylene glycol, 2) 0.5 mg alfaprostol (AP). 3) 1 mg AP, 4) 2 mg AP and 5) 3 mg AP. Sows received an intramuscular injection of AP between 0800 and 0830 on either day 111, 112 or 113 of gestation. Parameters studied included interval from injection to birth of first pig, farrowing interval, total number of pigs born, number born alive, average birth weight, percent stillborn, interval from weaning to next estrus and number born alive next litter. The mean intervals from injection to the birth of the first pig were 55.2 +/- 7.1; 41.1 +/- 5.1; 29.6 +/- 4.0; 24.3 +/- 1.1; 24.8 +/- 0.9 h for groups 1, 2, 3, 4 and 5, respectively (P<0.05). The percentage of sows that farrowed during normal working hours (23 to 33 h after injection) for groups 1, 2, 3, 4 and 5 were 15, 53, 60, 77 and 70%, respectively. Average birth weights (kg) for treatment groups 1, 2, 3, 4 and 5 were 1.54 +/- 0.05; 1.65 +/- 0.05; 1.59 +/- 0.05; 1.54 +/- 0.05 and 1.42 +/- 0.05, respectively (P<0.05). Mean differences in total number of pigs born and number born alive were also statistically significant (P<0.05) but stillbirth rate was not different (P>0.05) among treatment groups. These results indicate that a single injection of 1, 2 or 3 mg of alfaprostol will successfully induce parturition the following day in a majority of the treated sows.     

Supplying sows energy on the expected day of farrowing improves farrowing kinetics and newborn piglet performance in the first 24 h after birth

The farrowing process is one of the most energy-demanding activities for the modern hyperprolific sow. This study evaluated the effects of supply of energy on the expected date of farrowing on the farrowing kinetics and piglets’ performance during the first 24 h after birth. A total of 80 sows were used. The sows and their respective litters were considered as the experimental unit. On the expected day of farrowing, the sows were allocated to one of the following groups: sows that did not have access to feed from farrowing induction until the end of the farrowing process (CON, n = 40); sows fed 500 g of energetic supplement, which consisted of 250 g of the basal lactation diet plus 250 g of cane sugar, 18 h after farrowing induction (SUP, n = 40). The farrowing duration, farrowing assistance, birth interval, number of total born, stillborn and mummified piglets were recorded for each sow. Piglets were weighed individually at birth and 24 h later. The interval from birth to first suckle was evaluated individually for each piglet in 16 randomly selected litters (eight litters per treatment group). Blood glucose concentrations of six sows were measured shortly after expulsion of the first piglet. Farrowing duration, farrowing assistance and stillborn rate tended to be greater (P = 0.06, P = 0.09 and P = 0.07, respectively) in sows from the CON group compared to sows from the SUP group. However, there was no difference (P > 0.05) between the groups for birth interval. Colostrum intake was greater (P < 0.05) for piglets from the SUP group compared to piglets from the CON group. Additionally, BW gain of the piglets suckling the SUP group was greater (P < 0.05) than those suckling the CON group at 24 h after birth. The blood glucose concentrations during the expulsive stage of farrowing were greater (P < 0.05) in the SUP group than for sows from the CON group. In conclusion, supplying modern hyperprolific sows energy on the expected day of farrowing is a valuable nutritional intervention to improve the farrowing kinetics and piglets’ performance in early life.     

Sow behaviour and piglet weight gain after late cross-fostering in farrowing crates and pens

Determining best practices for managing free farrowing systems is crucial for uptake. Cross-fostering, the exchange of piglets between litters, is routinely performed amongst crate-housed sows. However, cross-fostering can increase fighting amongst the litter and may be more challenging within free farrowing systems as sows have more freedom to respond to cross-fostered piglets. This study compared the effect of either cross-fostering (FOS), or a control of sham-fostering (CON), of four focal piglets per litter on Day 6 postpartum in crates (CRATE) and free farrowing pens (PEN). The post-treatment behavioural responses of sows were recorded (Day 6 = 60 min; Day 7 = 300 min; n = 48), as were the average daily gain (ADG; g/day), total weight gain (TWG; kg) and body lesion scores of focal piglets and their littermates throughout lactation (Day 6, Day 8, Day 11 and Day 26; n = 539) and the post-weaning period (Day 29, Day 32 and Day 60; n = 108). On Day 6, though post-reunion latency to nursing did not differ, latency to successful nursing was longer amongst FOS than CON litters (P < 0.001), more so amongst CRATE FOS than PEN FOS (P < 0.01). On Day 7, PEN FOS sows had fewer successful nursing bouts (P < 0.05) and exhibited decreased lateral (P < 0.01) and increased ventral lying frequencies (P < 0.01) compared to all other housing and treatment combinations. Focal piglet ADG was lower for FOS than CON in the CRATE during Day 6 to Day 8 (P < 0.01) and lower in the PEN during Day 6 to Day 8 (P < 0.001), Day 8 to Day 11 (P < 0.01) and Day 11 to Day 26 (P < 0.05). The TWG of pre-weaned focal piglets (Day 6 to Day 26) was higher amongst CON than FOS litters (P = 0.01). Post-weaning, piglet ADG was higher for PEN than CRATE during Day 26 to Day 29 (P < 0.01) and higher for FOS than CON during Day 26 to Day 29 (P < 0.05), Day 29 to Day 32 (P < 0.001) and Day 32 to Day 60 (P < 0.01); thus, TWG was higher for FOS than CON during the weaner (P = 0.001) and the combined lactation and weaner periods (P = 0.09). In conclusion, sow behaviour was disrupted by cross-fostering in the crates and pens and continued to be disturbed on the following day amongst penned sows. FOS piglets exhibited reduced ADG after cross-fostering, which extended throughout lactation in the pens. However, the increased post-weaning weight gain of FOS piglets meant that their TWG was higher than CON piglets, irrespective of the farrowing system used.     

Source of oestrogen in early pregnancy in the mare

Oestrogen secretion was determined by oestrogen conjugate (EC) analysis of urine in three groups of pregnant mares: Group I (N = 6), animals ovariectomized on Day 18-19 of gestation with pregnancy maintained by daily administration of an oral progestagen, altrenogest; Group II (N = 9), untreated, pregnant mares; Group III (N = 5) intact, pregnant mares treated daily with altrenogest. The mean EC concentrations in the ovariectomized mares in Group I increased in a constant linear manner from 17 ng/mg Cr on Day 20 to 291 ng/mg Cr on Day 70, with no apparent surge in oestrogen secretion around Day 39. Mean EC concentrations on Days 33, 39 and 44 were respectively 41, 48, and 73 ng/mg Cr. In the intact mares in Groups II and III (shown in parentheses), the mean urinary EC concentrations were 201 (171) ng/mg Cr between Days 20 and 33 of gestation, increased rapidly from 172 (77) ng/mg Cr on Day 33 to a peak of 1066 (895) ng/mg Cr on Day 39, followed by a decline to 637 (719) ng/mg Cr on Day 44. After Day 44, EC concentrations continued to increase in a linear manner to 1191 (842) ng/mg Cr on Day 70. The mean EC concentrations between Days 20 and 70 in Group I were significantly (P less than 0.05) lower than in mares in Groups II and III. EC concentrations in Group III mares were significantly lower (P less than 0.05) than in Group II mares between Days 28 and 34.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of estradiol valerate on follicular dynamics and superovulatory response in cows with Syncro-Mate-B implants

Two experiments were designed to evaluate the effect of estradiol valerate on follicular dynamics and superovulatory response in cows with Syncro-Mate-B (SMB)implants. In Experiment 1, 5 mg estradiol valerate (E(2)), injected at the same time as superstimulation treatments were initiated, resulted in fewer corpora lutea (CL), ova/embryos collected and fertilized ova (P<0.05) than if E(2) was administered with the SMB implant 7 days earlier. In Experiment 2, 31 beef cows and 26 Holstein cows were placed in one of four treatment groups. Group I (control) cows were superstimulated on Day 9 (estrus=Day 0). On Day 2, cows in Groups II, III, and IV received SMB and cows in Group III received E(2). On Day 9, cows in Group IV received E(2), and all cows were superstimulated with Folltropin. The number of CL did not differ (P>0.19) among groups. However, there were more follicles < 10 mm and fewer fertilized ova and transferable embryos (P<0.02) in Group IV cows. Ovarian ultrasonography revealed that the diameter of the largest follicle in Group III cows declined from Day 2 to Day 7 and subsequently increased until Day 13. In contrast, Groups I, II and IV were characterized by apparently linear growth between Days 2 and 13. Differences (P<0.05) were detected between Days 5 and 9. Mean diameter of the largest follicle was smaller for cows in Group III than for the remaining groups on Day 9. It was concluded that SMB did not adversely affect superovulatory response and that E(2) administration resulted in atresia of the antral follicles in the cows with SMB implants.     

Factors affecting duration of the expulsive stage of parturition and piglet birth intervals in sows with uncomplicated, spontaneous farrowings

Modern pig farming is still confronted with high perinatal piglet losses which are mainly contributed to factors associated with the progress of piglet expulsion. Therefore the aim of this study was to identify sow- and piglet factors affecting the duration of the expulsive stage of farrowing and piglet birth intervals in spontaneous farrowing sows originating from five different breeds. In total 211 litters were investigated. Breed affected duration of the expulsive stage significantly: the shortest duration was found in Large White x Meishan F2 crossbred litters and the longest duration in Dutch Landrace litters. No effect of parity on the duration of the expulsive stage was found. An increase in littersize (P<0.01), an increase in number of stillborn piglets per litter (P<0.05) and a decrease of gestation length (P<0.05, independently of littersize) all resulted in an increased duration of the expulsive stage of farrowing. A curvilinear relationship between birth interval and rank (relative position in the birth order) of the piglets was found. Besides that, piglet birth intervals increased with an increasing birth weight (P<0.001). Stillborn (P<0.01) and posteriorly presented (P<0.05) piglets were delivered after significantly longer birth intervals than liveborn and anteriorly presented piglets. The results on sow- and piglet factors affecting duration of the expulsive stage and piglet birth intervals obtained in this study contribute to an increased insight into (patho) physiological aspects of perinatal mortality in pigs.