Immunohistochemical study of Ki-67 protein, androgen receptor, and estrogen receptor beta in testicular tissues of male pigs immunocastrated with different times of GnRH vaccination.

This study aimed to investigate the immunoexpression of Ki-67 protein, androgen receptor (AR), and estrogen receptor beta (ERß) in testicular tissues of male pigs immunocastrated using GnRH vaccine (Improvac™, Zoetis Co., Ltd., Thailand) with different times. Totally, 30 male pigs were classified by castration protocol into three groups: T1 (n = 10) consisted of pigs immunocastrated at 14 and 18 weeks of age, T2 (n = 10) included pigs immunocastrated at 9 and 19 weeks of age, and C (n = 10) contained intact pigs. The results revealed that testicular length of pigs in C was longer than that of both T1 (8.1 ± 0.76 vs 6.5 ± 0.5 cm, p < 0.001) and T2 (8.1 ± 0.76 vs 6.9 ± 1.0, p = 0.007). Spearman correlation coefficients showed negative correlation between testicular length and H-score of AR (r = -0.38, p = 0.037), as well as positive correlation between testicular length and Ki-67 index (r = 0.602, p < 0.001). Generally, mean Ki-67 index and mean H-scores of AR and ERß of pigs in T1 were not different from those in T2 (p > 0.05). However, mean Ki-67 index and mean AR H-scores of T1 and T2 were significantly different from C group (p < 0.05). In summary, the immunocastration significantly affected testicular length, including expressions of Ki-67, AR, and ERß in pig testes. Moreover, the duration between two shots of GnRH vaccine could be extended from 4 to 10 weeks without difference in Ki-67 protein, AR, and ERß immunoexpressions.

Reproductive performance of sows with and without PRRS modified live virus vaccination in PRRS-virus-seropositive herds.

Porcine reproductive and respiratory syndrome (PRRS) virus infection causes reproductive failures including return to oestrus, abortion, mummified foetuses, stillborn, and weak-born piglets. The objective of the present study was to investigate reproductive performance of sows in PRRS-virus-seropositive herds with and without PRRS modified live virus (PRRS-MLV) vaccination. The study was conducted in 20 PRRS-virus-seropositive commercial swine herds in Thailand. The data included 211,009 mating and 180,935 farrowing records. The analysed variables included farrowing rate (FR), return rate (RR), abortion rate (AR), total number of piglets born per litter (TB), number of piglets born alive per litter (BA), percentage of stillborn (SB), percentage of mummified foetuses (MM), and number of piglets weaned per litter (WP). The results revealed that FR in non-vaccinated sows was lower than that in vaccinated sows (85.0 vs 89.7%, respectively, P < 0.001), and RR in non-vaccinated sows was higher than that in vaccinated sows (6.9 vs 3.7%, respectively, P < 0.001). AR did not differ significantly between non-vaccinated and vaccinated sows (1.6 and 2.0%, respectively, P = 0.964). TB (11.2 and 11.5, respectively, P < 0.001), BA (10.0 and 10.6, respectively, P < 0.001), and WP (9.2 and 9.6, respectively, P < 0.001) in non-vaccinated sows were lower than those in vaccinated sows. SB (6.9 and 5.1%, respectively, P < 0.001) and MM (3.2 and 2.2%, respectively, P < 0.001) in PRRS-MLV-vaccinated sows were higher than those in non-vaccinated sows. The improvement in sow reproductive performance in PRRS-MLV-vaccinated herds was most pronounced in gilts and primiparous sows.

Reproductive parameters following a PRRS outbreak where a whole-herd PRRS MLV vaccination strategy was instituted post-outbreak.

This study assessed the effect of whole-herd porcine reproductive and respiratory syndrome (PRRS) modified-live virus (MLV) vaccination on herd-level reproductive performance, PRRS virus (PRRSV) viremia, and antibody in a subset of females in a 1,200-sow commercial herd in Thailand. Following a PRRSV outbreak, the entire herd was vaccinated with PRRS MLV twice at 3-week intervals and at 3-month intervals, thereafter. Reproductive performance data over a 3-year period were available for analysis. Serum samples were collected before and after vaccination and tested by PRRSV ELISA and reverse transcription-polymerase chain reaction. Vaccination was statistically associated with a lower abortion rate (1.4 vs. 1.6 %), farrowing rate (83.8 vs. 90.0 %), total born (10.6 vs. 11.4 piglets/litter), liveborn (10.0 vs. 10.3 piglets/litter), stillbirths (4.6 vs. 7.0 %), mummies (0.7 vs. 1.6 %), and a higher return rate (11.3 vs. 5.9 %) when compared with the period before the PRRSV outbreak. Pregnant females vaccinated during early gestation farrowed fewer liveborn and more mummies than the comparison group, whereas females vaccinated during late gestation had a lower farrowing rate. In this herd, PRRS whole-herd vaccination had neutral, positive, and negative effects on reproductive performance. Thus, the decision to implement whole-herd vaccination should be balanced between the benefits derived from reproductive performance improvements, e.g., fewer abortions, stillborn piglets, and mummified fetuses, and the effect of vaccination on pregnant females.

A preliminary study on using autologous and heterologous boar sperm supernatant from freezing processes as post-thawing solution: its effect on sperm motility.

The aim of this study was to evaluate the effect of post-thawing dilution with autologous and heterologous sperm supernatant on motility of frozen-thawed boar spermatozoa. During the cryopreservation, sperm supernatant (a combination of seminal plasma and semen extender, 50% v/v) or seminal plasma from nine boars (Duroc, Large White, and Landrace; three in each) was collected by centrifugation and stored frozen until use as post-thawing solution. Sperm pellets were further processed and cryopreserved using control-rate freezer and was thawed at 50°C for 12 s. After thawing, frozen thawed semen samples were diluted with seminal plasma (group A), supernatant from Landrace (group B), supernatant from Large White (group C), supernatant from Duroc (group D), and Modena™ semen extender (group E). Post-thawing motility was evaluated using a phase-contrast microscope after thawing at 1, 10, 20, and 30 min. The present results show that at 1 min, a significantly higher percentage (P ≤ 0.001) of progressive motility was found in groups B (53.3%) and C (53.9%) than the other groups. At 10 min, the highest (P ≤ 0.001) progressive motility was found in groups B (65%) and C (61%). At 20 and 30 min, a significantly higher percentage (P ≤ 0.001) of progressive motility was found in groups B (58.9%), C (53.5%), and D (45.6%) than groups A (3.9%) and E (20.6%). It can be stated that supernatant from the freezing processes (consisting of seminal plasma and Modena™, 50% v/v) had a beneficial effect on post-thawing progressive motility of frozen boar semen.

Prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissues in gilts culled due to reproductive disturbance in Thailand.

The objective of the present study was to determine the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissue in gilts culled due to reproductive disturbance in relation to age at culling, reasons for culling, herds, and PRRSV vaccination. Uterine tissues of 100 gilts from six swine herds in Thailand were collected. The immunohistochemistry was performed to detect the PRRSV antigen using a polymer-based non-avidin-biotin technique. PRRSV was detected in the cytoplasm of the macrophages in the subepithelial connective tissue layers of the endometrium in 33.0% of the culled gilts. The detection of PRRSV antigen varied among the herds from 14.3% to 80.0% (P = 0.018). The detection of PRRSV in the uterine tissues at different ages was not statistically different (29.6%, 39.4%, and 40.9% in gilts culled at 6-8, 9-10, and 11-16 months of age, respectively, P = 0.698), similar to the reasons for culling (P = 0.929). PRRSV antigen was found in 24.5% of the gilts vaccinated against the EU-strain-modified-live PRRSV vaccine and in 23.1% of the gilts vaccinated against the US-strain-modified-live PRRSV (P = 0.941). The level of antibody titers against PRRSV had no impact on PRRSV antigen detection in the uterine tissues. Similarly, the detection of PRRSV antigen did not differ between the virgin gilts (35.4%) and the gilts mated before culling (30.8%) (P = 0.622). It can be concluded that PRRSV remains in the uterine tissue of the infected gilts for several months even though vaccinations and acclimatization have been carried out.

Impact of porcine epidemic diarrhea virus infection at different periods of pregnancy on subsequent reproductive performance in gilts and sows.

Reproductive performance of gilts and sows in a swine commercial herd following an outbreak of porcine epidemic diarrhea virus (PEDV) were investigated. A PEDV outbreak was observed in March 2008 in a swine herd in Thailand. The disease was diagnosed by clinical symptoms, gross and histopathology and viral detection using reverse transcriptase-polymerase chain reaction assay. The intestines of the infected piglets were collected, minced and fed to all of the gilts and sows within 2 weeks after the onset of the PEDV outbreak. Reproductive data were collected during a period from January 2007 to July 2008 and were retrospectively evaluated. The farrowing rate (FR), return rate (RR), abortion rate (AR), number of total piglets born per litter (TB), number of piglets born alive per litter (BA), percentage of stillbirth piglets per litter (SB), percentage of mummified fetus per litter (MM) and piglet's birth weight (BW), before and after the PEDV outbreak were compared. It was found that the impact of PEDV infection on the reproductive performance of gilts and sows depended on the period of pregnancy when the females were exposed to the pathogen, and parity number. The pregnant females infected with PEDV during the first 30 days of pregnancy had a 12.6 percentage point decrease of FR (91.1% vs. 78.5%, P=0.003), a 5.7 percentage point increase of RR (3.5% vs. 9.2%, P=0.01), a 1.3 percentage point increase of AR (2.1% vs. 3.4%, P=0.01) and a 2.0 percentage point increase of MM (3.5% vs. 5.6%, P<0.001). SB increased in the pregnant females that were infected with PEDV during 91-120 days of pregnancy (1.8 percentage points, 4.5% vs. 6.2%, P=0.01). The impacts of PEDV infection on subsequent reproductive performance were more severe in the pregnant gilts than the pregnant sows. PEDV infection during the first 30 days of pregnancy resulted in a decrease of TB by 1.4 (11.7 vs. 10.3 piglets/litter, P<0.001) and a decrease of BA by 2.2 (10.7 vs. 8.5 piglets/litter, P<0.001) in the gilts' litters, while the influence of PEDV infection on TB and BA was not significant in sows (P>0.05). It was concluded that natural infection of PEDV in the pregnant gilts and sows caused a reduction of subsequent reproductive performance.

Influence of repeat-service and weaning-to-first-service interval on farrowing proportion of gilts and sows.

The present study was performed to evaluate different components of reproductive failure after service under a tropical climate and to investigate the influence of repeat-service and delayed wean-to-service interval (WSI) on subsequent fertility in gilts and sows. The study was conducted in four commercial swine breeding herds in the northeastern part of Thailand. Data were collected during a 3-year period from July 2005 to June 2008. A total of 30,058 insemination records from 9037 gilts and sows was included. On average, the farrowing proportion (FP) was 81.9% and adjusted FP (excluding gilts/sows culled after service) was 85.3%. The reasons for the failure to farrow included return-to-oestrus 9.4%, abortion 1.7%, not being pregnant 1.0% and not-in-pig 2.0%. Non-repeat-service females had 83.7% FP, while those that experienced repeat-serviced for 1, 2 and > or = 3 times had 71.2%, 57.7% and 43.4% FP, respectively (P<0.001). The seasonal influence on FP was observed in non-repeat-serviced females, but not in those that experienced repeat-service. Sows mated during 0-6 days after weaning had 86.8% FP, while those mated 7-10, 11-20 and 21-60 days after weaning had 78.9%, 78.9% and 78.4% FP, respectively (P<0.001). It is concluded that repeat-service in gilts/sows resulted in a 12.5% decrease in FP. Sows returning to oestrus later than 6 days after weaning had 7% lower FP than sows mated within 6 days after weaning.

The association between growth rate, body weight, backfat thickness and age at first observed oestrus in crossbred Landrace x Yorkshire gilts.

The present study aims to investigate the association between growth rate (GR), body weight (BW), backfat thickness (BF) and age at first observed oestrus in crossbred Landrace x Yorkshire (LY) replacement gilts in the tropics. The study was carried out on five commercial swine herds in Thailand between 2004 and 2006. A total of 6946 LY gilts were included. The gilts entered the herd at about 163 days of age. The BW (kg) and BF (mm) of the gilts were measured when the gilts entered the gilt pools and again when the gilts were sent to the breeding house. The GR from birth to entry into the gilt pools (birth to 90 kg BW) (GRe), the GR from entry into to exit from the gilt pools (91-134 kg BW) (GRi) and the GR from birth until the gilts were sent to the breeding house (birth to 134 kg BW) (GRs) were calculated. The relationship between age at first observed oestrus and GRe, GRs, GRi, BW and BF were analyzed. Pearson's correlation and four general linear models (GLMs) were conducted. On average, the gilts showed first observed oestrus at 200+/-28 days of age. The means of age at first observed oestrus varied from 188 to 251 days (P<0.001) among the herds. The GRs of the gilts significantly correlated with the BW (r=0.55, P<0.001) of the gilts when they were sent to the breeding house and the age at first observed oestrus (r=-0.40, P<0.001). Gilts with a high GRe and GRs were younger at first observed oestrus compared to gilts with a low GRe and GRs. On average, the gilts with GRs of over 604 g/day showed first observed oestrus before 5 months of age. GRi was not correlated with the age at first observed oestrus (P>0.05). Neither the BF of the gilts at entry nor the BF that the gilts gained within the gilt pools significantly correlated with age at first observed oestrus (P=0.29 and P=0.69, respectively). But the gilts with a higher BF at entry tended to have a higher BW when they were sent to the breeding house (r=0.44, P<0.001). The present study indicates that replacement gilts with a high GR (both GRe and GRs) tend to show sign of oestrus earlier than gilts with a low GR (both GRe and GRs).

Effect of temperature and humidity on reproductive performance of crossbred sows in Thailand.

This study investigated the influence of season, temperature, and humidity on the reproductive performance of sows under tropical conditions. Data were collected from 11 sow herds from January 2001 to June 2002. Temperature and humidity were recorded daily for each herd from January 2001 to February 2002. Semen used was collected from boars housed in conventional open-air stables (six herds) or in evaporative cooling stables (five herds). A total of 43,875 farrowing records were included in the statistical analysis. Fourteen-day moving averages of daily maximum temperature and minimum humidity were calculated and merged with each reproductive record. ANOVA was applied to the reproductive records. In addition to the fixed effects included in the statistical models (e.g. system, season, parity, temperature, and humidity), the random effect of herd within system was included. The total number of piglets born was analyzed in relation to the climate at previous weaning (NTB-w), at mating (NTB-m), and at farrowing (NTB-f). The housing system of the boars had no significant effect on any of the reproductive variables analyzed. Season (2-month periods) as well as parity number had a significant effect on all reproductive variables analyzed. Increased length of previous lactation had a significant and favorable effect (P < 0.001) on NTB-w, NTB-m, and weaning-to-first-service interval. There were indications that high temperature and humidity (recorded at the herd level) at previous weaning/mating or at farrowing had negative effects on litter size, but these negative influences were not consistent.

Effect of temperature and humidity on sperm morphology in duroc boars under different housing systems in Thailand.

The aim of this study was to investigate the effect of season, temperature, humidity, age of the boar, and semen collection interval on sperm morphology in Duroc boars in Thailand, kept either in a conventional open air system (CONV) or in an evaporative cooling system (EVAP). In total, 1176 ejaculates from 110 sexually mature boars in six CONV herds and five EVAP herds were morphologically examined during a one-year period. Analysis of variance was applied to the data. Minor differences in the sperm morphology traits analyzed were found between the housing systems. There was a significant seasonal effect (two-month periods) on the percentage of morphologically normal spermatozoa (normal1), morphologically normal spermatozoa including spermatozoa with distal cytoplasmic droplets (normal2), proximal cytoplasmic droplets (prox), and sperm head abnormalities (P

Management and sperm production of boars under differing environmental conditions.

The management of boars to ensure good sperm production under differing environmental conditions is a major concern for pig keepers in both tropical countries and countries where there are extreme environmental changes. Such changes create stress in animals and influence the production of spermatozoa. High temperatures during hot summer months may result in lower feed consumption and create stresses that result in the inhibition of spermatogenesis. Although tropical countries do not have a problem with major variations in day length, this can cause problems such as decreased litter size and infertility in other regions of the world. Evaporative cooling systems built into boar accommodation are often used to reduce fluctuations in both temperature and humidity during the hot and humid months seen in tropical countries. The system has become popular in AI boar studs, where it is reported to reduce stress and improve feed consumption. Other management factors, such as housing comfort, social contact, mating conditions and the frequency of mating, are also very important boar management aids that assist good quality semen production; these will be covered briefly in this review. This review will consider primarily those management factors, for example, the management of temperature and humidity using evaporative cooling systems and other techniques that enable AI boar studs to maximize sperm fertility through adjustments to the environment.

Effect of season and outdoor climate on litter size at birth in purebred landrace and yorkshire sows in Thailand.

The objective of the present study was to retrospectively investigate causes of variation on litter size at birth (total number of piglets born per litter (TB) and number of piglets born alive per litter (BA)) of Landrace (L) and Yorkshire (Y) sows in swine nucleus herds in Thailand. The data included sows farrowed during a four-year period from January 1998 to December 2001. The analyzed data set included observations on 8020 litters from 2199 L sows and 6919 litters from 1680 Y sows. Analysis of variance (ANOVA) was applied for statistical analyses using General Linear Mixed Model (MIXED) procedure of SAS. No breed difference was found for both TB and BA. Farrowing months significantly influenced TB and BA (P<0.001). Sows farrowed in August and September had a lower BA than sows farrowed from November to June (P<0.05). Effect of farrowing months on both TB and BA was more pronounced in primiparous compared with multiparous sows. Average minimum daily temperature during gestation negatively correlated with both TB and BA, average maximum daily temperature during gestation negatively correlated with BA and average daily humidity during gestation negatively correlated with both TB and BA. The correlations were stronger in L than in Y sows.

The effect of activation protocols on the development of cloned goat embryos.

This study was conducted to compare the developmental competence of somatic nuclear transfer (NT) embryos, after either ionomycin or ethanol activation, in locally bred goats. Donor cells were prepared from the ear skin fibroblasts of a female goat. Cells, at passage 3-8, starved by culturing in 0.5% FCS for 4-8 d, were used for NT. Immature oocytes were obtained from FSH-stimulated goats and matured for 22 hr before enucleation and NT. After fusion, the reconstructed embryos were activated with either ionomycin or ethanol followed by culturing in 6-dimethylaminopurine (6-DMAP) and cytochalasin B (CB), for 3 hr. In experiment I, the fused NT embryos (n=63, ionomycin and n=68, ethanol treatments, respectively) were cultured in B2 with a Vero co-culture system and their developmental competence was evaluated through to Day 9. In experiment II, the NT embryos at the 2-4 cell stage on Day 2 derived from each treatment (ionomycin n=46, and ethanol n=37), were transferred into 10 synchronous recipients. There were no significant differences between the NT embryos derived from the ionomycin and ethanol groups, in fusion (86.3% versus 82.9%), cleavage (90.5% versus 82.4%) and for morula/blastocyst development rates (9.5% versus 5.9%). Sixty percent (3/5) of the recipients from ionomycin became pregnant by midterm (2.5 mts) while only 20% (1/5) from ethanol treatment was pregnant by Day 45. The results demonstrate that activation with either ionomycin or ethanol in combination with 6-DMAP-CB treatment does not affect the development of cloned goat embryos.

A study on the number of recovered spermatozoa in the uterine horns and oviducts of gilts, after fractionated or non-fractionated insemination.

The objective of this study was to compare the number of recovered spermatozoa, in different parts of the uterine horn and oviduct in gilts, after insemination with fractionated (experiment) and non-fractionated (control) liquid stored semen. The number of spermatozoa and volume of backflow was also investigated. Twenty three cross-bred gilts were used in the study. They were divided into 2 groups, a control group (non-fractionated liquid stored semen, n=10) which were inseminated with 100 ml of liquid stored semen containing 3,000 million spermatozoa per dose and an experimental group (fractionated liquid stored semen, n=10) which were inseminated with 50 ml of liquid stored semen, with 3,000 million spermatozoa per dose and followed by another 50 ml of semen dilutor (Beltsville Thawing Solution, BTS). Thereafter, backflow semen was collected and measured every 15 min for a period of 1 hr. Three or 12 hr after insemination, 5 gilts from each group had the uterus, the horn of the uterus, the oviducts and the ovaries removed under general anaesthesia. The horn of uterus and the oviducts were seperated by ligation into 6 segments. All 6 segments were flushed with BTS to collect all spermatozoa within the segment. Recovered spermatozoa were counted, using a haemocytometer and the volume recorded. It was seen that the percentage of spermatozoa in the backflow semen in the experimental group was less than in the control group. The difference was not significant in the gilts that were operated on 3 hr after insemination, the mean number of spermatozoa in the uterine horn and the utero-tubular junction (UTJ) was more in the experimental than in the control group, but less in the isthmus and the ampulla of the oviduct. The gilts which were operated on 12 hr after insemination, had relativity more ovulating gilts in the control group than in the experimental group (3 of 4 gilts compare to 3 of 5 gilts). The control group had more spermatozoa in the oviduct than the experimental group, but less in UTJ and in the horn of the uterus. Again the difference was not significant. It can be concluded that fractionated (experimental) or non-fractionated (control) insemination of semen with the same number of spermatozoa provides no significant difference in the number of spermatozoa either in the horn of the uterus, the UTJ or the oviduct of gilts.