Teaser Boar Research Articles

Reproductive health indicators of sows using azoxymer bromide

The aim of the research was to study the effect of different regimens of using «Azoxivet» on the duration of pregnancy, labor and restoration of sexual cycling in sows. «Azoxivet» is a synthesized immunomodulator with detoxicant and antioxidant properties. The active substance «Azoxivet» is azoxymer bromide. The research was carried out on sows of the large white breed, live weight of 180-230 kg, which had 1-4 farrowings in anamnesis. 90 sows at 80 days of gestation were divided into 3 groups . Sows of group 1 (G1, n=30) were injected with «Azoxivet» intramuscularly 3 times in interval of 7 days from the 100th day of gestation at a dose of 0.1-0.15 mg/kg (18 mg). Sows of group 2 (G2) were injected with «Azoxivet» twice at 100th days of gestation and on the day of farrowing at the same dose. Sows of group 3 (G3) was control. Clinical observation of sows were conducted during pregnancy, in time of labor and in postpartum periods. In sows, we took into account the pregnancy rate, the course of labor, the restoration of sexual cyclicity after weaning of piglets. The presence of the estrus was detected in once a day in the morning hours with using a teaser boar. Artificial insemination (AI) efficiency was determined on 28th day with ultrasound. Data were analyzed by MIXED of SAS program. The gestation periods in sows in G1, G2 and G3 were 114.50 ± 0.28, 114.86 ± 0.26 and 114.72 ± 0.19 days, respectively. In G3, 3.33% of the sows had a pregnancy pathology caused by an abortion on 105th day . In G1 and G2, no pregnancy pathologies were revealed. The greatest duration of the labor act was recorded in G3 - 234.63 ± 18.71 min, while in G1 and G2 the labor was lasted 27.13 and 34.86 min less. In G1 and G2, labor complications were observed only in 13.64% and 14.28% of females, while in G3 - in 36.84% of sows. After weaning piglets and transferring sows to the section of barren sows, recovery of sexual cyclicity was registered in 81.48% in G3, which is 6.98% and 10.52% less than in G1 and G2. In all groups, the manifestation of estrus was observed for 4-6 days. The average duration from weaning to the manifestation of estrus in animals G1 was 4.60 ± 0.22 days, in G2 - 4.65 ± 0.13 days, in G3 - 4.32 ± 0.10 days. The effectiveness of AI according to the results of an ultrasound carried out on the 28-30th day after insemination was high in all studied groups and amounted to 95.65-100%. Consequently, the using «Azoksivet» has a positive effect on the pregnancy, the course of their labor process and the activation the sexual cyclicity after weaning of piglets, ensures high fertility of sows and increases the duration of the economic using of animals.

Effects of individual versus group housing system during the weaning-to-estrus interval on reproductive performance of sows

Selection of appropriate housing conditions for sows is critical for their physical health and long-term reproductive success. The present objective was to evaluate the influences of housing system postweaning (i.e., individual stalls (IS) or group pens (GP)), season and parity on piglet productivity of sows in a commercial setting. This study utilized 3 053 Polish Large White×Polish Landrace sows that were weaned at a rate of 20–30 animals per week at the median age of 4 weeks; 1 474 sows were moved into GP of seven to eight animals each, while 1 579 were placed in IS after weaning. Starting 2 days postweaning all animals were checked for estrus with a teaser boar and then artificially inseminated using 3×109 spermatozoa per dose of an inseminate at the onset of heat and 24 h later. The proportion of sows showing the signs of standing heat at or before 6 days postweaning was greater (P < 0.05) for sows moved to GP compared with IS; this difference manifested mainly in second parity sows weaned in the summer and fall. Conception and farrowing rates were significantly higher (P < 0.01) and the weaning-to-estrus interval shorter in GP compared with IS sows in every season but autumn. Mean litter size was lower (P < 0.05) in IS groups in summer, autumn, and winter, and the number of live-born piglets/sow was lower (P < 0.05) for IS sows in the summer and fall. Beneficial effects of group housing on piglet productivity manifested up until the seventh consecutive farrowing and then began to wane. In summary, there was a significantly greater proportion of sows going estrus “on time” (i.e., <7 days) in group housing compared to single stalls but this effect was confined to the second parity sows during the summer and fall months; these results suggest the existence of a seasonal and age-related aspect to sow fertility worthy of further investigation. While both housing systems have their pros and cons, our present results indicate that, in commercial settings, group housing postweaning improved nearly all reproductive parameters of sows.

The influence of azaperone treatment at weaning on reproductive performance of sows: altering effects of season and parity

Azaperone treatment can control aggression and decrease stress due to weaning, re-grouping and hierarchical fighting of gilts and sows. However, the effects of this butyrophenone neuroleptic and sedative administered at weaning on pig reproductive function are poorly characterized. In this year-long study, a total of 619 cross-bred sows (Polish Large White×Polish Landrace) kept on a commercial farm received an i.m. injection of azaperone (Stresnil®; 2 mg/kg BW) just before weaning and were artificially inseminated during the ensuing estrus with 3×109 spermatozoa per dose of an inseminate; 1180 sows served as untreated controls. Immediately after weaning, the sows were moved to four pens of seven to nine animals each. A teaser boar was used twice daily to check for estrus and sows were bred at heat detection. Subsequently, all sows stayed in individual stalls until pregnancy testing on day 30 post-artificial insemination and were then re-grouped until farrowing. The proportion of pigs that were in estrus within 6 days post-weaning was significantly lower in azaperone-treated groups of animals than in controls (71.4% v. 84.2%). Overall, the azaperone-treated sows had a significantly longer weaning-to-estrus interval (WEI; 8.7±10.1 v. 6.3±8.1 days; mean±SD) and a significantly larger litter size (LS: 11.8±3.0 v.11.3±3.2; azaperone-treated v. control sows). Treatment of the winter-farrowing sows was associated with increased LS (12.8±2.6 and 11.3±3.1 piglets/sow, respectively; P<0.05) and longer (P<0.05) weaning-to-effective-service intervals (11.7±19.3 and 8.4±12.3 days, respectively) as well as farrowing intervals (155.7±19.7 and 152.2±16.1 days, respectively) compared with untreated controls. In the summer months, significantly longer WEIs (12.1±21.0 v. 8.4±16.9 days) were accompanied by a significant decline in LS only in azaperone-treated sows that were inseminated within 6 days post-weaning (10.8±2.9 v. 11.5±3.3 piglets/sow; azaperone-treated v. controls). Azaperone-treated second parity sows had greater LS (P<0.001) along with prolonged WEIs (P<0.05) in comparison to their respective controls, regardless of the timing of estrus. An application of azaperone at weaning increased the annual piglet productivity of winter-farrowing animals and of second parity sows but depressed it significantly in summer. The extra cost and labor due to delayed onset of estrus may cancel out any reproductive benefits of azaperone treatment.

Impact of Prl and Fst Loci Polymorphism on Sexual Activity of Puławska Gilts* *

Abstract PRL (prolactin) and FST (follistatin) genes were investigated and analysed with regard to values of selected indices determining the reproductive activity of gilts in heat. The performed analyses comprised gilts of Puławska breed kept within the framework of the Genetic Resources Protection Programme of Farm Animals. Ninety-six gilts were phenotyped (one set for FST and one set for PRL). Each genotype (PRL, FST) group was represented by an equinumerous population of 32 gilts. The analysis took into consideration the second and third spontaneous oestrus during which the following parameters were assessed: age, body weight, duration of the tolerance reflex in the phase of true oestrus and intensity of reproductive responses during the oestrus period. The sexual behaviour was estimated with the assistance of: the manual method, mounting with a simultaneous pressure with knees of the lumbosacral area, and using a teaser boar in accordance with a 3-point score. The performed experiments revealed a significant impact of polymorphism in the FST locus on oestrous activity. On the other hand, the PRL gene was found to affect feeding behaviour, motor activity (including oestrous) and contributed to lack of motor activity treated as rest or sleep.

The use of digital infrared thermal imaging to detect estrus in gilts

Yorkshire/Landrace crossbred gilts (N = 32) were evaluated using digital infrared thermal imaging (DITI) to discriminate between estrus and diestrus phases of the porcine estrous cycle. Gilts (N = 32) were part of an ongoing reproductive efficiency study involving the use of raw soybean (RSB; N = 15) versus soybean meal (SBM; N = 17) as a source of dietary protein. Gilts were monitored daily for signs of estrus using a teaser boar. Thermal images of vulva surface temperatures (TEMP) were recorded at standing estrus and diestrus. Measurements for analysis included minimum (MIN), maximum (MAX), mean (AVG), and standard deviation (SD) of temperature gradients. At imaging, ambient (AMB) and rectal temperatures (RT) were recorded, and blood samples taken for serum progesterone (P4) concentration analysis (by RIA) to confirm stage of cycle. Mean serum progesterone values at estrus and diestrus were (mean ± SD) 1.0 ± 0.1 and 10.9 ± 0.8 ng/mL, respectively. Vulva MIN, MAX, and AVG thermal images were positively correlated with one another (P < 0.01), and were positively correlated with ambient temperature (P < 0.01). Vulva MAX and AVG thermal temperatures were greater (P < 0.05) at estrus than at diestrus (36.6 ± 0.2 °C and 33.4 ± 0.3 °C vs. 35.6 ± 0.3 °C and 31.8 ± 0.6 °C, respectively), whereas MIN and SD had no differences (P > 0.05) between stages of the cycle. No differences (P > 0.05) in RT were detected between stages and RT was not significantly correlated with vulva thermal images. Diet had no significant effect on RT or vulva temperature.

Effects of (artificial) boar stimuli on uterine activity in estrous sows

This study aims to examine influences of specific boar stimuli on uterine activity in estrous sows, by comparing uterine activity in presence of a mature teaser boar and a robot boar with variable stimuli. Nineteen multiparous, cyclic, commercial crossbred sows were used. Intra-luminal uterine pressure was measured using a non-surgical method for 45 min before applying one of four treatments in combination with a back-pressure-test (BPT): (1) robot with olfactory and auditory stimuli (R + O + A) ( n = 16), (2) robot with auditory stimuli (R + A) ( n = 16), (3) robot without additional stimuli (R) ( n = 16), (4) a mature boar (boar) ( n = 15). After treatment, measurements continued for 30 min. For each measurement, frequency, mean amplitude and mean duration of uterine contractions were determined. Spontaneous frequency of uterine contractions was 18.6 ± 0.7 h −1 on average and did not differ between treatments. Frequency of contractions increased significantly for the boar (+5.6 ± 1.3 h −1; P < 0.01), R + O + A (+3.9 ± 1.3; P < 0.01) and R + A (+2.6 ± 1.3; P < 0.05). The effect of boar presence on frequency of contractions was greater than the effect of R ( P < 0.05). Amplitude and duration of contractions were not affected by treatment. The change in frequency was dependent on spontaneous frequency ( P < 0.01). In conclusion, the higher the level of boar stimuli, the greater the increase in frequency of uterine contractions. The results indicate that the used combinations of artificial boar stimuli do not mimic a ‘whole’ boar. It is unclear which boar stimuli stimulate maximal uterine activity during estrus.

Effect of boar contact on follicular development and on estrus expression after weaning in primiparous sows

Boar contact can induce ovarian activity, advance estrus and stimulate estrous behavior in sows. High amounts of boar contact can, however, suppress estrous behaviour. The present study with primiparous sows was designed to compare sows that had contact with a teaser boar during detection of estrus, with sows that had no boar contact at all. Number of sows detected in estrus within 9 d after weaning, onset and duration of estrus, follicular dynamics and timing of ovulation were studied. Boar contact increased the number of sows that ovulated and showed estrus from 14 of 47 to 24 of 47 ( P < 0.05). Average timing of ovulation was later for sows with boar contact (165 h vs 150 h after weaning). Duration of estrus, detected without a boar, was similar in the two groups. For the sows with boar contact, duration of estrus detected with a boar was longer than estrus detected without a boar (56 vs 38 h; P < .01). Follicular dynamics were not affected by boar contact; boar contact only increased the number of sows with ovulation. Ovulatory sows showed a larger increase in follicular diameter ( P < 0.01) from weaning to Day 4 after weaning (from 2.3 to 5.4 mm) than anovulatory sows (from 2.5 to 4 mm). Anovulatory sows did not show follicular growth after Day 4. It is concluded that boar contact can increase the number of sows that ovulate and show estrus after weaning. Estrous behavior does not seem to be suppressed by contact with a teaser boar, compared to sows without boar contact.

Effects of boar contact and housing conditions on estrus expression in weaned sows.

Our objective was to study the effects of housing conditions and the amount of boar contact in a protocol for estrus detection on estrus detection rate, timing of onset of estrus, duration of estrus, and timing of ovulation. After weaning, 130 multiparous sows were assigned to three treatments: HI, in which 52 sows were housed individually in crates and received a high amount of boar contact during estrus detection; HG, in which 52 sows were housed in groups and received a high amount of boar contact; and NI, in which 26 sows were housed individually in crates and received a normal amount of boar contact. Estrus detection was performed every 8 h. For each treatment, the standing response to three levels of stimuli was recorded: a back pressure test (BPT) by a man (man-estrus), presence of a teaser boar (spontaneous-estrus), and BPT in the presence of a teaser boar (boar-estrus). In addition, for HI and HG, the standing response to a fourth level of stimuli was recorded: BPT in a detection-mating area, surrounded by four boar pens (DMA-estrus). To detect ovulation, ultrasonography was performed every 4 h during estrus. Of 117 sows that ovulated, 46% showed man-estrus, 56% spontaneous-estrus, 90% boar-estrus, and 97% DMA-estrus. Mean onset of man-estrus was 107 h (SD 26) after weaning, of spontaneous-estrus was 106 h (SD 22) after weaning, of boar-estrus was 99 h (SD 21) after weaning, and of DMA-estrus was 93 h (SD 22) after weaning. Duration of man-estrus was 22 h (SD 14), of spontaneous-estrus was 29 h (SD 16), of boar-estrus was 42 h (SD 20), and of DMA-estrus was 55 h (SD 18). The high amount of boar contact reduced the number of sows showing man-estrus (P < .05; 41% for HG and HI vs 68% for NI) and reduced duration of boar-estrus (P < .05; 43 h for HG and HI vs 52 h for NI). Duration of DMA-estrus for HG and HI was similar to duration of boar-estrus for NI. Onset of estrus and timing of ovulation were not affected by amount of boar contact. Group housing did not affect detection rate and duration of estrus, but it did postpone average onset of estrus by 10 h, paralleled by a postponement of ovulation. In conclusion, estrus expression is similar at the highest level of stimuli in different protocols for estrus detection. Including higher levels of stimuli in a protocol reduces estrus expression at lower levels of stimuli. This reduction indicates adaptation of sows to a given protocol for estrus detection. Group housing can delay ovulation and related behavioral estrus.

LH profile and advancement of ovulation after transcervical infusion of seminal plasma at different stages of oestrus in gilts.

The influence of a transcervical infusion of seminal plasma on preovulatory LH profiles and the advancement of ovulation after seminal plasma infusion for different times during oestrus were investigated using the single uterine horn infusion technique (Mariensee model), in combination with transcutaneous sonographic monitoring of the ovaries. Preparative surgery in 23 German Landrace gilts comprised the detachment of the left uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. In six gilts fitted with a permanent jugular vein catheter the patent horns were administered a transcervical infusion of seminal plasma (n = 5 cycles) or PBS (n = 4 cycles) immediately after the detection of oestrus by a teaser boar. In addition, 17 non-catheterized gilts received infusions of seminal plasma either 0 h (n = 3 gilts), 16 h (n = 7 gilts) or 24 h (n = 7 gilts) after the detection of oestrus. Seminal plasma infusion at the onset of oestrus provoked ovulation in the ipsilateral ovary of the treated horn 8.5 +/- 0.9 h earlier than in the contralateral (control) ovary. Seminal plasma did not influence the LH profile compared with PBS (P > 0.05), but shortened the interval between the LH peak and ipsilateral ovulation to 23.4 +/- 4.0 h compared with 31.8 +/- 3.4 h in the contralateral ovulation (P < or = 0.01). Infusion 16 h after the onset of oestrus reduced the effect to 4.6 +/- 3.8 h with a wide range of 0-8 h (P < 0.01). The effect was more pronounced in gilts with long intervals between the onset of oestrus and contralateral ovulation compared with earlier ovulation on the control ovary. Seminal plasma infusion less than 16 h before contralateral ovulation and 24 h after the detection of oestrus had no effect. It is concluded that transcervical infusion of seminal plasma early in oestrus synchronizes the variable intervals between the onset of oestrus and ovulation in sows by a locally active mechanism.

The effect of storage time and number of spermatozoa per insemination dose on semen characteristics and fertilizing capacity of boar semen diluted with Beltsville Thaw Solution (BTS) extender

AbstractSemen collection from three boars was performed twice a week, and doses (100 ml each) of semen diluted with Beltsville Thaw Solution (BTS) extender were prepared containing 1 × 109, 3 × 109 and 5 × 109 spermatozoa. Diluted semen was then stored at 17°C for a maximum of 120 h. Percentage of motile spermatozoa (PMS) and type of spermatozoa motility (TSM) were determined by microscopic examinations performed at 24-h intervals, from zero time (beginning of storage at 17°C) up to 120 h of storage, and a sperm motility index (SMI) calculated. Sows (no. = 360) were divided into nine experimental groups (40 sows per group) and a combination of number of spermatozoa per dose and storage time was used for artificial insemination in each group. All the animals were inseminated twice at 12 and 36 h after detection of standing oestrus by a teaser boar. Return and farrowing data including litter size were recorded. PMS, TSM and SMI decreased significantly (P &lt; 0·01) from 48 h up to 120 h of storage, this being more marked in semen doses of 5 × 109 spermatozoa. When semen stored for up to 24 h was used, no significant differences (P &gt; 0·05) regarding return rates and farrowing rates were observed among the three groups inseminated with semen containing different numbers of spermatozoa per dose. Inseminations with semen doses of 1 × 109 and 3 × 109 spermatozoa stored for 48 to 72 h have significantly lower return rates (P &lt; 0·05) and significantly higher farrowing rates (P &lt; 0·05) than with doses of 5 × 109 spermatozoa. Inseminations with semen stored for more than 72 h gave relatively higher return rates and lower farrowing rates. Semen storage time and number of spermatozoa per dose appeared to reduce litter size only where semen doses of 5 X109 spermatozoa were inseminated after storage for more than 48 h.

Advanced ovulation in gilts by the intrauterine application of a low molecular mass pronase-sensitive fraction of boar seminal plasma

The shortening of the time interval between the onset of oestrus and ovulation in sows by the transcervical administration of seminal plasma was investigated in 23 German Landrace gilts, using the technique of single horn infusions (Mariensee model) in combination with the transcutaneous sonographic monitoring of ovaries. Preparative surgery comprised the detachment of the left uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. The left ovary was loosely tied to the ventral abdominal wall for better sonographic distinction. The animals were used in two to four consecutive cycles. After detection of oestrus by the teaser boar, the patent (right) horns were filled by transcervical infusion of 100 ml of a variety of test solutions. Ovulation was probed by transcutaneous sonography at intervals of 4 h thereafter. Native seminal plasma provoked ovulation in the ipsilateral ovary of the treated horn 10.7 h earlier than in the contralateral ovary. This effect was reduced to 7.3 h after charcoal treatment of seminal plasma; addition of 10 micrograms oestradiol restored the effect in full, while 10 micrograms of oestradiol in PBS shortened the time interval to only 3.3 h versus the control ovary. Little effect was seen with oestrone sulfate, none with prostaglandins in PBS or with PBS alone. The preliminary characterization of the nonsteroidal component of seminal plasma advancing ipsilateral ovulation after transcervical infusion suggests a proteinaceous nature. The activity resides in the 1-10 kDa fraction separated by ultrafiltration and is lost after treatment with pronase.

Proceptive and receptive aspects of oestrus behaviour in gilts

Proceptive and receptive aspects of behaviour were studied during the oestrus cycle of the female pig. These aspects were studied in a T-maze with one or two stimulus compartments that did or did not contain a teaser boar. Receptive behaviour was observed during several consecutive days and was quantified in front of the boar by using the back pressure test (BPT). Three aspects of proceptive behaviour, i.e. the tendency to ‘search the boar’, ‘stay close to the boar’ and ‘to present’ in front of the boar peaked in the middle of the receptive period, and in most gilts on the day preceding the last receptive day (Experiment 1). In contrast, preference for a particular boar, another aspects of proceptive behaviour, was only expressed during the days preceding and following the receptive period (Experiment 2). The results are discussed in terms of the possible functional implications of proceptive and receptive behaviour in relation to fertilization.

Effectiveness of frozen boar semen under practical conditions of artificial insemination

A technique of boar semen deep-freezing and frozen semen use was tested in practice. 338 sows and 43 gilts belonging to small herds with less than 10 females each were inseminated without oestrus detection by a teaser boar. About 58 % of the inseminated females produced 9.3 piglets per litter. But there were differences between parities. The sows had the highest fertility rate, whereas the gilts showed a significantly lower farrowing rate (59.8% vs 41.9%; P < 0.05). The standing reaction of the female to the back pressure test made by the inseminator and the behaviour of the female during insemination had an effect on the farrowing rate. The best result was obtained after a standing reaction and a behaviour score of 1 (64.5% and 9.6 piglets for farrowing rate and litters size respectively). Farrowing rate for inseminators ranged from 44.3% to 62.4% among inseminators. Farrowing rate for females inseminated with frozen semen from Large-White, Landrace, Pietrain boars was not different, but there were significant differences between the boars. Results showed that insemination with deep-frozen boar semen could be used under practical conditions as an additional technique to the use of fresh semen.