Metabarcoding of feces and intestinal contents to determine carnivorous diets in red-crowned cranes in eastern Hokkaido,Japan

The red-crowned crane Grus japonensis in Hokkaido, Japan forms a closed population as a residence that is independent of the mainland population. Based on observations of a limited number of individuals as well as cranes in captivity, red-crowned cranes are omnivores and eat fish, worms, insects and plants in their own territories except in winter, when they are fed with dent corn that is supplied in eastern Hokkaido. DNA metabarcoding based on high throughput sequencing was carried out using universal primer sets for cytochrome oxidase subunit I gene. Feces from 27 chicks collected in June and July in the period from 2016 to 2018 and intestinal contents from 33 adult and subadult cranes that were found dead almost throughout year in 2006–2013 in the field in eastern Hokkaido were used. Although compositions varied considerably in the cranes, both insects and fish were found in adults and subadults to the same extents, while insects were predominant in chicks. Both insects and fish were detected in all seasons for adults and subadults. Horse flies, scarab beetles and weevils accounted for the most of the insects regardless of the life stage. Dace, stickleback, flatfish and sculpin were the major fish species in adults, while chicks ate almost only stickleback. The results provide the first comprehensive data on carnivorous diets in wild red-crowned cranes in eastern Hokkaido as basis for conservation of red-crowned cranes, for which the life style and area continue to change.     

Prevalence of Shiga toxin-producing Escherichia coli in Yezo sika deer (Cervus nippon yesoensis) in the Tokachi sub-prefecture of Hokkaido,Japan

In food hygiene, the surveillance of foodborne pathogens in wild animals is indispensable because we cannot control hygienic status of them. Yezo sika deer (Cervus nippon yesoensis), which are found only on the island of Hokkaido, Japan, are the most common game animal in the country. In this study, we analyzed the incidence of Shiga toxin-producing Escherichia coli (STEC) in Yezo sika deer hunted in the Tokachi sub-prefecture, which is one of the densest zones for the sub-species. Real-time polymerase chain reaction testing detected STEC in 18.3% of fecal samples (59/323) collected from deer hunted between 2016 and 2017, whereas no Shigella and Salmonella markers were detected. No correlation was found between STEC detection from fecal samples and characteristics of carcasses, such as hunting area, age, and fascioliasis. From 59 STEC-positive fecal samples, we isolated 37 STEC strains, including 34 O- and H-genotyped strains, in which 16 different serogroups were detected. Genetic analysis revealed that our isolates included various stx gene types (stx1⁺/stx2⁻, stx1⁺/stx2⁺, and stx1⁻/stx2⁺) and carried eae. This study demonstrated that STEC strains with various features colonized the Yezo sika deer, similar to other subspecies of sika deer. We conclude that continuous surveillance activity is important to monitor the suitability of game animals as a food source and to assess the validity of the food safety management system for game meat production.     

Molecular epidemiological characterization of poultry red mite, Dermanyssus gallinae,in Japan

Dermanyssus gallinae, the poultry red mite, is an obligatory blood-sucking ectoparasite. The genetic diversity of D. gallinae has been examined in some countries, but so far not in Asian countries. Here, we sequenced a part of the mitochondrial cytochrome oxidase subunit I (COI) and16S rRNA genes and nuclear internal transcribed spacers (ITS) region in 239 mite samples collected from 40 prefectures throughout Japan. The COI and 16S rRNA nucleotide sequences were classified into 28 and 26 haplotypes, respectively. In phylogenetic trees, the haplotypes clustered into 2 haplogroups corresponding to haplogroups A and B, which were previously reported. Haplogroups A and B were further subdivided into sub-haplogroups AJ1 and AJ2, and BJ1 and BJ2, respectively. In both trees, the sequences of haplotypes in AJ1 and BJ2 were relatively distant from those reported in other countries, while some sequences in AJ2 and BJ1 were identical to those in Europe. In addition, the ITS sequences were classified into two sequences, and both sequences were closely related to the sequences found in European countries. These findings indicate a possibility of international oversea transmission of D. gallinae.     

Mitochondrial diversity of native pigs in the mainland South and South-east Asian countries and its relationships between local wild boars

In this study, we analyzed DNA sequence of mitochondrial DNA (mtDNA) control regions on the 130 native domestic pigs and eight wild boars in the mainland South and South-east Asian countries including Bhutan, Cambodia, Laos, Myanmar, and Vietnam. Forty-four haplotypes were found in the 138 individuals, 41 were in the domestic and four were in wild boars. Only one haplotype was shared by domestic and wild population in Bhutan. In other cases, mtDNA of wild boars did not show close affinity to that of the domestic pigs in the same location, indicating that the native domestic pigs in these countries did not originate in the present habitat. Phylogenetic analyzes of mtDNA haplotypes recapitulated several major clusters identified in other studies, but 11 haplotypes were grouped in a new cluster we named MTSEA. In most cases, more than one lineage group were present in a sampling station, indicating that the present indigenous domestic pigs may have multiple origins. The MTSEA haplotypes were present in relatively high frequencies in domestic pigs in the mountainous area of mainland South-east Asia (Cambodia and Laos), with a few found in Myanmar and Bhutan. The distributions of MTSEA haplotypes are in great conformity with the distribution of present-day Mon-Khmer language and indicated the existence of yet another independent domestication. The D2 haplotypes that distribute high frequency (almost 100%) throughout the Chinese breeds were dominant in Bhutan, Myanmar, and Vietnam. These results suggest an existence of human-mediated dispersal of domestic pigs from north to the south during the historical expansion of Sino-Tibetan and Tai peoples. The D3 haplotypes previously reported in north India were found in sympatric domestic and wild pigs in Bhutan. The D3 haplotype is an important proof of independent domestication event and/or great gene flow between wild and domestic pigs in the foot of Himalaya.     

Genetic characterization of a small closed island population of Norwegian coastal goat

ABSTRACT

The Norwegian coastal goat is a national and endangered breed. Coastal goat populations are mainly divided with a large mainland and two small island populations. The objective of this study is to describe genetic diversity in the feral Skorpa island population and its relationship to the mainland coastal goat population (Selje) using the Norwegian milk goat population as a reference. Analyses were based on 96 samples genotyped by the CaprineSNP50 Beadchip from three populations; 7 Skorpa (SK), 37 Selje (SE) and 52 Norwegian milk goats (MG). The SK population had significantly less genetic variation and higher levels of inbreeding than the two other populations. It was more distant from the two mainland populations than they were from each other. The marginal contribution of the SK population to genetic diversity was small. Means of introducing genetic diversity into the SK population should be considered if the population is prioritized for conservation.     

Investigation of the occurrence of Angiostrongylus vasorum in coyotes in southern Ontario,Canada

In North America, the only endemic focus for Angiostrongylus vasorum (French heartworm) was historically thought to occur in the southeastern part of the island of Newfoundland. However, reports of A. vasorum infection in wild canids in West Virginia, USA, and Nova Scotia, Canada, suggest the introduction of the parasite to mainland North America. We screened for A. vasorum in coyotes from across southern Ontario. Additionally, we evaluated the performance of ELISAs for detection of circulating A. vasorum antigen (Ag-ELISA) and antibodies against A. vasorum (Ab-ELISA) designed for use in sera or blood of foxes for use with coyotes in this region. Autopsies were performed on 397 coyotes, and lung tissue extract prepared from each carcass was tested via both ELISAs. The sensitivity and specificity for both tests were estimated in the absence of a gold standard using a 2-test single population Bayesian model; sensitivity and specificity priors were based on the performance of the assays in foxes in Switzerland. Eight coyotes tested positive for A. vasorum antigen; no animal was antibody positive. The estimated sensitivity and specificity of the Ag-ELISA were 90.8% (95% credible interval [CrI]: 83.8–95.6%) and 95.5% (95% CrI: 93.4–97.2%), respectively. For the Ab-ELISA, the estimated sensitivity and specificity were 41.9% (95% CrI: 32.1–51.9%) and 98.0% (95% CrI: 96.3–99.0%), respectively. Based on these findings and negative postmortem data for the same animals, there is insufficient evidence to suggest the presence of A. vasorum in southern Ontario coyotes.     

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido

The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.     

Association between melanocortin 4 receptor (MC4R) gene haplotypes and carcass and production traits in Italian Large White pigs evaluated with a selective genotyping approach

Melanocortin 4 receptor (MC4R) plays a key role in controlling energy homeostasis. Several studies have already reported effects on production traits of polymorphisms identified in the porcine MC4R gene. In this study we analysed data on 6 MC4R polymorphisms (c.-780C>G; c.-135C>T; c.175C>T; c.707G>A or p.Arg236His; and c.892G>A or p.Asp298Asn; c.?430A>T) genotyped from (1) two groups of Italian Large White pigs (280+280 animals) with extreme estimated breeding values (EBVs) for back fat thickness (BFT), selected among a performance tested population of about 12,000 pigs, and from (2) 19 Italian Duroc pigs. Two haplotypes, differentiated by the c.892G>A, were identified in the Duroc populations. Four haplotypes were identified in the Italian Large White population, one of which (haplotype 4) was identified for the first time in this study. Single marker and haplotype association analyses for BFT were obtained by comparing allele and haplotype frequency differences from the two extreme tails using χ² and Cochran–Armitage trend tests. Results confirmed the effects of the c.892G>A single nucleotide polymorphism (SNP) on BFT, as also defined by different distributions in the two tails of haplotypes carrying the alternative nucleotides at this polymorphic site (P<0.01). In addition different distributions of haplotype 4 in the two extreme groups suggested that it might affect the same trait (P<0.10). Association analyses for several other traits (average daily gain, ADG; feed gain ratio, FGR; weight of lean cuts; ham weight) were carried out by using EBVs and Random Residuals: significant effects (P<0.05) were only found for the p.Asp298Asn mutation on ADG and FGR. Results did not support any relevant effect of the p.Arg236His mutation on any trait. Data reported in this study contribute to better understand the role of MC4R variants in affecting production traits in pigs, a prerequisite to consider polymorphisms in this gene for marker assisted selection.     

Polymorphism of FSHR Gene Exon 10 and Its Relationship with the Litter Size of Xiang Pigs

Follicle-stimulating hormone (FSH), a glycoprotein secreted from pituitary, can regulate ovarian function through the FSH receptor (FSHR).To evaluate the effects of FSHR gene on the litter size of Xiang pig population, the polymorphisms of FSHR gene exon 10 were detected by polymerase chain reaction (PCR) and sequencing methods, and the effect of polymorphisms in FSHR gene exon 10 on litter size traits in Xiang pigs was analyzed using the least square analysis.In eight candidate sites, there were two polymorphic loci were detected out from Xiang pig population, which were rs322800083 (C276T) and rs332115220 (T601C). Moreover, a new SNP novel 1 (G-92A) was discovered.Four haplotypes were constructed between rs322800083 and rs332115220 sites, in which C-T was the main haplotype (45.0%) and presented closely linkage disequilibrium (r²=0.334) in Xiang pig population. Furthermore, the haplotype C-T corresponded to the highest total number born (TNB) at the second fetus of Xiang pigs, haplotype C-C to the lowest TNB. It was notified that haplotype C-T produced 0.99 TNB of Xiang pigs more than haplotype C-C (P<0.05). And the TNB at the third fetus was also the highest in haplotype C-T, which produced 1.61 and 2.33 TNB more than haplotypes T-C and C-C (P<0.01). The genotypes of locus rs332115220 was weakly correlated with the third fetus of Xiang pig population (ρ=0.429).The results suggested that haplotype C-T could be used as a molecular marker to assist selection for the litter size of Xiang pigs.     

香猪FSHR基因外显子10的多态性及其与产仔数间的关联分析

促卵泡激素（follicle-stimulating hormone,FSH）是垂体前叶分泌的一种糖蛋白,可通过卵泡刺激素受体（follicle-stimulating hormone receptor,FSHR）调节卵巢的功能。为了研究香猪FSHR基因外显子10的多态性及其与产仔数的关系,试验以从江香猪为研究对象,采用PCR产物直接测序方法检测基因的多态性,分析基因型与香猪产仔数间的关系。对8个候选位点进行群体检测证实其中2个为SNPs位点,分别是rs322800083（C276T）和rs332115220（T601C）,且新发现1个SNP位点novel 1（G-92A）;rs322800083和rs332115220位点构成4种单倍型,其中C-T为香猪群体的主要单倍型（45.0%）,且在香猪群体中紧密连锁（r²=0.334）。分析4种单倍型与香猪产仔数间的关系,在香猪的二胎产仔数中,单倍型C-T的总产仔数（total number born,TNB）最高,单倍型C-C的TNB最低,两者之间的TNB相差0.99头（P<0.05）;在香猪的三胎产仔数中,单倍型C-T的TNB最高,与单倍型T-C、C-C间的TNB分别相差1.61和2.33头（P<0.01）。rs332115220位点的基因型与香猪的三胎产仔数呈弱的正相关关系（ρ=0.429）。本研究结果提示,单倍型C-T可以作为分子标记应用于香猪产仔数性状的辅助选育。     

Distribution of the mutant allele of the DMRT3 gene associated with ambling gaits in Japanese native horse populations

There are currently eight native horse populations in Japan, namely, Hokkaido, Kiso, Noma, Taishu, Misaki, Tokara, Miyako, and Yonaguni horses. Since locomotion traits, including gaitedness, are important for riding and packing horses, the genetic properties associated with these traits could be informative for understanding the characteristics and history of these horses. In this study, we investigated the distribution of the mutant allele of DMRT3 gene (DMRT3:p.Ser301Ter) associated with ambling gaits in the Japanese native horse. We also examined haplotypes of SNPs in the 83‐kb region including DMRT3 gene by genotyping four SNPs in this region. The results revealed the presence of DMRT3:p.Ser301Ter in the Hokkaido and Yonaguni populations at allele frequencies of 0.18 and 0.02, respectively, and the observed haplotype associated with DMRT3:p.Ser301Ter was estimated as the most common haplotype in the horses in the world. Since DMRT3:p.Ser301Ter has been hypothesized to spread across Eurasian continent from Medieval England after 850 to 900 CE, our findings of the presence of DMRT3:p.Ser301Ter with the common haplotype in the Japanese native horses will provide a new insight into the history of the Japanese native horse, such as considerable level of gene flow from Eurasian continent after 850 to 900 CE.     

Comparative genotyping of Blastocystis infecting cattle and human in the south of Iran

BackgroundBlastocystis is a unicellular protozoan and one of the most common parasites found in humans and many animals' intestinal tract. The present study aimed to compare the genotypes of Blastocystis infecting cattle and humans in the south of Iran.MethodsA total of 100 human stool samples and 75 cattle stool samples were microscopically examined for Blastocystis infection. DNA was extracted from thirty-eight microscopically positive samples (13 humans and 25 cattle). PCR was performed on positive samples targeting the Blastocystis-specific SSU rDNA gene. PCR products of eight humans and eleven cattle samples were sequenced and compared with available reference sequences in GenBank by BLAST queries. Genetic diversity was measured for Blastocystis subtypes in human and cattle, based on haplotype and nucleotide diversities.ResultsThe PCR detected Blastocystis in ten humans and twenty-four cattle samples. Blastocystis subtypes 1, 2, and 6 were found in humans whereas subtypes 5 and 10 were found in cattle. Subtype (ST) 2 was the most predominant subtypes in humans whereas, in cattle specimens, the ST5 was the most dominant subtype. Based on the Blastocystis sequences of SSU rDNA, 68 sites were polymorphic and 49 sites were parsimony informative, resulting in the identification of 15 haplotypes, 10 haplotypes in the cattle and 5 in humans. No haplotype was shared between cattle and human parasites.ConclusionHuman-derived Blastocystis subtypes were different from cattle subtypes in southern Iran. Nevertheless, subtype 5 in cattle can be a risk factor for human infection.     

Novel harmful recessive haplotypes for reproductive traits in pigs

Harmful recessive haplotypes for reproductive and fertility traits have previously been detected in cattle, but so far, no studies have been published for pigs. The aim of this study was to locate chromosomal regions with putative lethal haplotypes and estimate the effects of the identified haplotypes on reproductive traits in the Finnish Yorkshire pig breed. We used marker genotypes of 871 Finnish Yorkshire AI boars, genotyped with Illumina's PorcineSNP60 BeadChip. The analysed traits were number of stillborn piglets in first (NSB1) and later (NSB2) parities, total number of piglets born in first and later parities and piglet mortality between birth and weaning in first and later parities. A haplotype was claimed as a putative lethal if it was common in the population, but no homozygous animals were found. We detected altogether 26 putative lethal haplotypes, but only one haplotype on chromosome 8 (position 107.0–113.3 Mb) was significantly associated with traits NSB1 and NSB2. Three possible candidate genes were found in this chromosomal region: MAD2LI, FGF2 and ANXA5. Further analysis is needed to confirm the role of these genes on pig reproductive performance.     

Genetic structure of the oriental white stork (Ciconia boyciana): implications for a breeding colony in a non‐breeding area

The oriental white stork (Ciconia boyciana) is a threatened species, and their numbers are still in decline due to habitat loss and poaching. China is a breeding and main wintering area for this animal and in recent years some individuals have been found breeding in wintering areas and at some stopover sites. These new breeding colonies are an exciting sign, however, little is understood of the genetic structure of this species. Based on the analysis of a 463‐bp mitochondrial DNA (mtDNA) control region, we investigated the genetic structure and genetic diversity of 66 wild oriental white storks from a Chinese population. We analyzed the sequences of 66 storks obtained in this study and the data of 17 storks from a Japanese population. Thirty‐seven different haplotypes were detected among the 83 samples. An analysis of molecular variance showed a significant population subdivision between the two populations (F_ST= 0.316, P < 0.05). However, the phylogenetic analysis revealed that the samples from the different populations did not form separate clusters and that there were genetic exchanges between the two populations. Compared with the Japanese population, the Chinese population had a relatively higher genetic diversity with a haplotype diversity (hπ SD) of 0.953 ± 0.013 and a nucleotide diversity (π± SD) of 0.013 ± 0.007. The high haplotype diversity and low nucleotide diversity indicate that this population might be in a rapidly increasing period from a small effective population. A neighbor‐joining tree analysis indicated that genetic exchange had occurred between the newly arisen southern breeding colony and the northern breeding colony wintering in the middle and lower Yangtze River floodplain. These results have important implications for the conservation of the oriental white stork population in China.     

Evaluation of associations between prion haplotypes and growth, carcass, and meat quality traits in a Dorset x Romanov sheep population

There is concern about potential antagonistic correlated responses due to intensive selection for scrapie-resistant haplotypes of the prion (PRNP) gene in sheep. The objective of the present research was to test for associations of PRNP haplotypes for codons 136, 154, and 171 with growth, carcass, and meat quality traits in an F2 Dorset x Romanov population (n = 415) segregating the 2 callipyge alleles. Haplotypes of the 3 PRNP codons were determined for each sheep, and breed of origin of each gamete was predicted by genotyping 6 microsatellite markers flanking the PRNP locus. Twenty-five growth, carcass, and meat quality traits were evaluated. Data were analyzed using a basic model consisting of fixed effects of year, sex, and callipyge genotype, the random effect of sire, and 7 covariates corresponding to the probability that a lamb inherited a specific PRNP haplotype of either Dorset or Romanov origin. A fixed effect of litter size was added to the model for growth traits. The model for carcass traits contained the linear and quadratic effects of chilled carcass weight and the interactions among callipyge genotype and linear and quadratic terms. For meat quality traits, the model contained chilled carcass weight as a covariate and the interaction between callipyge genotype and chilled carcass weight. A contrast between the resistant ARR haplotype and the average effect of other PRNP haplotypes was tested to investigate the effects of potential selection for ARR within each breed of origin (Dorset, ARR vs. ARQ, VRQ, and AHQ; Romanov, ARR vs. ARQ and VRQ). There was limited evidence that selecting for scrapie resistance would cause correlated responses due to linkage disequilibrium. Associations of only 3 traits with PRNP haplotypes were detected in either breed of origin. In Romanov, the ARR haplotype was associated with longer carcasses (P < 0.013), narrower rumps (P = 0.038), and less marbling (P = 0.022) than the average of ARQ and VRQ haplotypes. No significant contrasts were detected for Dorset. This study is the first to account for breed of origin while investigating haplotype associations in an F2 population. This study provided limited evidence of associations between PRNP haplotypes and growth, carcass, and meat quality traits.     

Anti-Brucella antibodies in seals at coastal locations of Hokkaido,Japan, with focus on life stages

The enzyme-linked immunosorbent assay (ELISA) was applied to detect antibodies against Brucella abortus in serum samples from four seal species at nine coastal locations of Hokkaido, Japan. These antibodies were detected in 27% (32/118) of Western Pacific harbor seals (Phoca vitulina stejnegeri) at Cape Erimo. The antibodies were observed in spotted seals (P. largha) in one out of six at Nemuro, in two out of three at Rebun Island, in one out of two at Bakkai, and in examined one at Soya. They were also found in respective examined one ribbon seal (Histriophoca fasciata) and one ringed seal (Pusa hispida) at Akkeshi. Harbor seals that tested positive were mostly yearlings (35%, 20/57) and juveniles (45%, 10/22), while only one pup (1/13) and one subadult (1/5) tested positive with low titers of the antibody; no antibodies were observed in adults (n=21). These results suggest that Brucella mainly infected harbor seals from the environment while weaning, and the bacteria were cleared during the early life stage of the seals. In spotted seals, however, antibodies were also detected in adults, suggesting that spotted seals could become infected with Brucella even as adults. It is also possible that a different, more persistent strain of Brucella may have infected the spotted seals.     

Geographical variation of skull size and shape in various populations in the black giant squirrel

We osteometrically examined the skulls of the black giant squirrel (Ratufa bicolor) from three mainland populations (M. Malayan Peninsula, V. South Vietnam, and B. Burma, India and North Thailand) and from two island populations (T. Tioman, and S. Sumatra Islands). The skull in the Malayan peninsula population was significantly smaller than that of the two other mainland populations. It is consistent with Bergmann's rule as shown in the gray-bellied squirrel. The two island populations did not show obvious differences in comparison with the Malayan population in many measurements. In the proportion analysis eliminating the size factor, the differences among populations were not easily confirmed and we concluded that the osteological characters peculiar to each population could not be shown in this species. The first and second principal component scores of M, S, and T populations were intermingled, whereas the V and B populations of V and B were not separated in the chart. We pointed out that the morphological differences were demonstrated between northern and southern groups of the Isthmus of Kra in the mainland populations, and that the two island populations did not show the island-isolation effect in comparison with the M population. The adaptational variation related to feeding and locomotion could not be confirmed among populations of the black giant squirrel as shown in the proportion analysis.     

基于ND2基因的崖沙燕遗传多样性和遗传结构初探

利用线粒体DNA中的NADH脱氢酶第二亚基(ND2)对来自齐齐哈尔市50个崖沙燕(Riparia riparia)样本进行扩增和测序,发现了11条新的单倍型序列。结合从GenB ank中下载的104条序列,对崖沙燕3个亚种种群(154只个体)进行序列变异及系统发育分析。结果显示,3个亚种种群中有2个共享单倍型。群体总的单倍型多样性(Hd)为(0. 885±0. 019),群体总的核苷酸多样性(Pi)为(0. 002 92±0. 000 18)。与其近缘物种淡色崖沙燕(Riparia diluta)相比较,崖沙燕种群表现出较低水平的遗传多样性。分子方差分析(AMOVA)显示变异主要来自种群内(72. 82%)。构建的单倍型系统发育树表明,62个单倍型没有形成明显的亚种分化和地理分化。     

High amino acid variation in the intracellular domain of the pig prolactin receptor (PRLR) and its relation to ovulation rate and piglet survival traits

Two polymorphisms of the porcine prolactin receptor (PRLR) gene were previously related to litter size by several authors; however, the magnitude and direction of such effects varied depending on the population analyzed. We have sequenced the complete coding region of the porcine PRLR gene and found 6 nonconservative SNP: C1217T (Leu/Pro406), C1283A (Asp/Ala428), G1439A (Lys/Arg480), T1528A (Met/Leu510), G1600A (Gly/Ser534), and G1789A (Gly/Ser597), within exon 10 of the gene, which encodes the entire intracytoplasmic domain of the protein. Eight haplotypes were found and were segregating at different frequencies in 6 porcine breeds. The effects of each individual SNP and haplotype were evaluated in an Iberian x Meishan F2 population using a univariate mixed-inheritance animal model. Significant effects on the number of corpora lutea were found for PRLR haplotypes (P < 0.012), confirming the previously reported associations of PRLR in this process and highlighting the importance of performing analysis of haplotypes rather than of individual SNP. Suggestive effects or tendencies were found for heart rate at birth (P < 0.10), rectal temperature (P < 0.05), and oxygen saturation (P < 0.10) 1 h after birth, and time to first suckle (P < 0.10). We found greater than expected levels of amino acid variability within the intracellular domain of the porcine PRLR, which have been associated with differences in the number of corpus lutea of sows and the preweaning survivability of piglets.