Seasonal effect on semen availability and quality of racing pigeon in Thailand.

BACKGROUND AND AIM: Seasonal variations among geographical regions could influence pigeon semen quality differently. This study aimed to determine the seasonal effect on semen availability and quality of racing pigeons in Thailand to understand and improve breeding management in the country. MATERIALS AND METHODS: Semen was collected from six fertile captive pigeons once a week during summer (March-June), monsoon (July-October), and winter (November-February) during 2019-2020. The success rate of semen collection and semen quality was determined in each season - by which changes in average temperature, humidity, and photoperiod were obtained. RESULTS: Comparable success rates of semen collection were acquired among different seasons, while varied semen qualities were revealed. The percentages of total motility and progressive motility score of sperm were significantly lowest in summer (66.35±3.40 and 3.88±0.15, respectively) compared to monsoon (85.45±2.91 and 4.67±0.10, respectively) and winter (79.29±1.96 and 4.37±0.10, respectively), while its concentration (×109 sperm/mL) and outputs (×106 sperm) were significantly highest in winter (7.62±0.54 and 91.44±10.83, respectively) compared to summer (4.23±0.41 and 48.45±6.35, respectively) and monsoon (3.57±0.30 and 51.45±7.21, respectively). Besides, semen samples collected from birds housing at an average temperature of <29.5°C demonstrated better sperm motility sperm concentration and total sperm counts than those from at a higher temperature. CONCLUSION: Winter was regarded as the best season contributing the best semen quality, while summer was the worst. Due to the fluctuation of temperature during summer and winter, the seasonal temperature was implied as the major factor contributing to changes in sperm quality of racing pigeons in Thailand.

Fetal mortality associated with backfat thickness at first mating and first farrowing of the primiparous sows raised in a commercial herd in Thailand.

This study aimed to investigate the fetal mortality, including stillborn piglets (SB) and mummified fetuses (MM), in relation to backfat thickness both at first mating (MBF) and at first farrowing (FBF) in 200 primiparous sows accommodated in a commercial breeding herd in Thailand. Backfat thickness of all pigs was measured at P2 position using an A-mode ultrasonography. Based on MBF, the gilts were classified into four groups: MBF1 (≤12.0 mm), MBF2 (>12.0-15.0 mm), MBF3 (>15.0-18.0 mm), and MBF4 (>18.0 mm). According to FBF, the primiparous sows were categorized into four classes: FBF1 (≤15.0 mm), FBF2 (>15.0-18.0 mm), FBF3 (>18.0-21.0 mm), and FBF4 (>21.0 mm). At farrowing, 174 litters were examined for percentage of SB and MM. The results indicated that mean MBF and FBF were 16.7 ± 0.3 mm and 19.6 ± 0.3 mm, respectively. Based on MBF, the pigs in MBF1 significantly possessed higher percentage of MM (13.8 ± 4.5%) than others; meanwhile, SB percentage was not different among groups (P > 0.05). According to FBF, the pigs in FBF4 farrowed the highest percentage of SB (9.1 ± 3.2%) than others, whereas MM percentage was not different among classes (P > 0.05). In summary, backfat thickness of the gilts should be one of the parameters to pay more attention since it is related to fetal mortality of the primiparous sows. The farmers should monitor the backfat thickness not only at the first mating time, but also along the gestation period in order to minimize fetal mortality in the primiparous sows.

Differential DNA methylation analysis across the promoter regions using methylated DNA immunoprecipitation sequencing profiling of porcine loin muscle.

BACKGROUND AND AIM: Pork leanness and marbling are among the essential traits of consumer preference. To acquire knowledge about universal epigenetic regulations for improving breed selection, a meta-analysis of methylated DNA immunoprecipitation sequencing (MeDIP-seq) profiling data of mixed loin muscle types was performed in this study. MATERIALS AND METHODS: MeDIP-seq profiling datasets of longissimus dorsi muscle and psoas major muscles from male and female pigs of Landrace and Tibetan breeds were preprocessed and aligned to the porcine genome. Analysis of differential methylated DNA regions (DMRs) between the breeds was performed by focusing on transcription start sites (TSSs) of known genes (-20,000-3000 bases from TSS). All associated genes were further reviewed for their functions and predicted for transcription factors (TF) possibly associated with their TSSs. RESULTS: When the methylation levels of DMRs in TSS regions of Landrace breed were compared to those of Tibetan breed, 10 DMRs were hypomethylated (Landrace < Tibetan), and 19 DMRs were hypermethylated (Landrace > Tibetan), accordingly (p≤0.001). According to the reviews about gene functions, all associated genes were pieces of evidence for their roles in a variety of muscle and lipid metabolisms. Prediction of the binding TFs revealed the six most abundant binding TFs to such DMRs-associated TSS (p≤0.0001) as follows: ZNF384, Foxd3, IRF1, KLF9, EWSR1-FLI1, HES5, and TFAP2A. CONCLUSION: Common DMRs-associated TSS between the lean-type and the marbled-type loin muscles were identified in this study. Interestingly, the genes associated with such regions were strongly evidenced for their possible roles on the muscle trait characteristics by which further novel research topics could be focused on them in the future.

Prevalence of porcine reproductive and respiratory syndrome virus detection in aborted fetuses, mummified fetuses and stillborn piglets using quantitative polymerase chain reaction.

The objective of the present study was to investigate the prevalence of porcine reproductive and respiratory syndrome (PRRS) virus detection in aborted fetuses (n=32), mummified fetuses (n=30) and stillborn piglets (n=27) from 10 swine herds in Thailand using quantitative polymerase chain reaction (qPCR). Pooled organs and umbilical cord from each fetus/piglet were homogenized and subjected to RNA extraction and cDNA synthesis. The qPCR was carried out on the ORF7 of the PRRS viral genome using fluorogenic probes for amplified product detection. The results revealed that 67.4% (60/89) of the specimens contained PRRS virus. The virus was found in 65.6% (21/32) of aborted fetuses, 63.3% (19/30) of mummified fetuses and 74.1% (20/27) of stillborn piglets (P=0.664). Genotype 1, genotype 2 and mixed genotypes of PRRS virus were detected in 19.1% (17/89), 25.8% (23/89) and 22.5% (20/89) of the specimens, respectively (P=0.316). PRRS virus antigen was retrieved from both non-PRRS-vaccinated herds (68.2%, 45/66) and PRRS-vaccinated herds (65.2%, 15/23) (P=0.794). These findings indicated that these specimens are important sources of the PRRS viral load and the viral shedding within the herd. Thus, intensive care on the routine management of dead fetuses and stillborn piglets in PRRS virus-positive herds should be emphasized.

Influence of growth rate and onset of boar contact on puberty attainment of replacement gilts raised in Thailand.

This study aimed to investigate the influence of growth rate and onset of boar contact on age at first observed estrus of the replacement gilts raised in Thailand. In total, 766 gilts were measured for body weight and backfat thickness prior to insemination. Body weight was further calculated for growth rate. Estrus detection was performed twice a day by back pressure test with an existence of mature boars with high libido. The first date of boar exposure and that of first observed estrus were individually recorded. Due to growth rate, they were classified into three groups: high (>700 g/day), moderate (600-700 g/day), and low (<600 g/day). According to onset of boar contact, the gilts were grouped into two categories: early (<150 days) and late (≥150 days). The results revealed that the gilts expressed first observed estrus, averagely, at age 205.1 ± 34.1 days, had a growth rate of 615.5 ± 57.6 g/day, and first contact with boars at 160.7 ± 19.9 days of age. The gilts with low growth rate expressed first estrus later than those with moderate (208.6 ± 2.0 vs 198.0 ± 3.2 days, P = 0.033) and high growth rate (208.6 ± 2.0 vs 193.9 ± 6.7 days, P = 0.005) groups. Together with the influence of boar exposure, the gilts contacted boar earlier with high growth rate showed first estrus at age 180.3 ± 10.1 days, whereas those with later boar contact with low growth rate showed first estrus at age 197.9 ± 3.2 days. In summary, the replacement gilts should have high growth rate and contact boar early to attain puberty faster and possess decent subsequent reproductive performance.

Conception rate and litter size in multiparous sows after intrauterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand.

The aim of the present study was to determine the conception rate and litter size in sows after fixed time intra-uterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand. Sixty-nine Landrace multiparous sows were randomly allocated into two groups, including control (n=36) and treatment (n=33). The control sows were inseminated with extended fresh semen (3 × 10(9) motile sperm/dose, 100 ml) at 24, 36 and 48 hr after the onset of estrus. The treatment sows were inseminated with frozen-thawed semen (2 × 10(9) motile sperm/dose, 20 ml) at 24 and 36 hr after induction of ovulation by human chorionic gonadotropin. All inseminations were carried out by using an intra-uterine insemination technique. The time of ovulation was determined by using transrectal real-time B-mode ultrasonography. The conception rate, farrowing rate, total number of piglets born/litter (TB) and number of piglets born alive/litter (BA) were evaluated. The sows inseminated with extended fresh semen yield a higher TB (10.8 versus 9.0 piglets/l, P=0.015) and tended to have a higher conception rate (88.9% versus 75.8%, P=0.150) than sows inseminated with frozen-thawed semen. In conclusion, insemination using frozen-thawed boar semen can be practiced with convinced fertility under field conditions by fixed-time intrauterine insemination with 2 × 10(9) sperm/ dose of 20 ml at 24 and 36 hr after the onset of estrus.

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.

Porcine reproductive and respiratory syndrome virus detection in Thailand during 2005-2010 in relation to clinical problems, pig types, regions, and seasons.

The objectives of the present study were to determine the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) in Thailand between 2005 and 2010. The study was conducted by retrospectively investigating the detection of PRRSV from different pig types including boars, sows, piglets, nursery pigs, and fattening pigs from six regions of Thailand, i.e., the northern, eastern, northeastern, central, western, and southern parts. The data were obtained from cases submitted to the Chulalongkorn University Veterinary Diagnostic Laboratory for PRRSV detection between 2005 and 2010. Frequency analyses and generalized linear models were used to evaluate the prevalence of PRRSV in relation to various factors. In total, 2,273 tissues (n = 636), semen (n = 210) and serum (n = 1,427) samples were included. PRRSV was detected in 32.6 % (740/2,273) of the pigs. The virus was found in 43.1 %, 15.7 %, and 30.3 % in the tissues, semen, and serum samples, respectively (P < 0.001). The prevalence of PRRSV was highest in 2005 (43.6 %) and lowest in 2009 (23.6 %) (P < 0.001). The prevalence of PRRSV was highest in nursery pigs (43.7 %) and lowest in boars (15.4 %) (P < 0.001). The prevalence of PRRSV in the hot season (34.9 %) was higher than that found in the cool season (28.1 %, P = 0.018) but did not differ significantly compared to rainy season (34.0 %, P = 0.486). The strain of PRRSV isolated in the present study was genotype 2 (54.5 %), genotype 1 (31.0 %), and mixed genotypes (14.5 %). It can be concluded that PRRSV was detected in the tissue samples more frequently than the semen and serum samples. The prevalence of PRRSV was high in the nursery pigs. A high prevalence of PRRSV was found in the hot season, indicating that climatic factors may also contribute to the prevalence of PRRSV in Thailand. Of all the PRRSV detected, 31.0 %, 54.5 %, and 14.5 % belonged to genotype 1, genotype 2, and mixed genotypes, respectively.

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.

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.