Postmortem findings in cloned and transgenic piglets dead before weaning

Important factors contributing to the well-known high mortality of piglets produced by SCNT are gross malformations of vital organs. The aim of the present retrospective study was to describe malformations found in cloned piglets, transgenic or not, dying or culled before weaning on Day 28. Large White (LW) embryos were transferred to 78 LW recipients, while 72 recipients received Göttingen embryos (67 transgenic and five not transgenic) and 56 received Yucatan embryos (43 transgenic and 13 not transgenic). Overall pregnancy rate was 76%, and there were more abortions in recipients with minipig embryos than in those with LW embryos (26% and 24% vs. 6%). Piglets (n = 815) were born from 128 sows with 6.5 ± 0.4 full-born piglets per litter. The overall rate of stillborn piglets was 21% of all born with the number of stillborn piglets ranging from one to nine in a litter. The mortality of the surviving piglets during the first month was 48%. Thus, altogether 58% of the full-born piglets died before weaning. In 87 of the 128 litters (68%), one to 12 of the piglets showed major or minor malformations. Malformations were found in 232 piglets (29.5% of all born). A single malformation was registered in 152 piglets, but several piglets showed two (n = 58) or more (n = 23) malformations (7.4% and 2.8% of all born, respectively). A significantly higher malformation rate was found in transgenic Göttingen and Yucatan piglets (32% and 46% of all born, respectively) than in nontransgenic LW (17%). There was a gender difference in the transgenic minipigs because male piglets had a higher rate of malformations (49.1%) than females (29.7%). The most common defects in the cloned piglets were in the digestive (12.2%), circulatory (9.4%), reproductive (11.3%), and musculoskeletal (9.1%) systems. Malformations of the musculoskeletal system were most frequent in Göttingen (16.3% vs. approximately 5.5% in the two other breeds), whereas abnormal cardiopulmonary systems were most frequent in Yucatan piglets (26.9% vs. 2.1% in LW and 5.3% in Göttingen). In conclusion, these results show that pig cloning results in a considerable loss of piglets and that many of these can be related to various malformations that all are also seen in noncloned piglets. Because approximately half of the cloned piglets still survive, even with eventual unknown minor malformations, use of pigs as models for human diseases is still realistic. However, continued efforts are needed to further reduce the level of malformations.

A complex malformation in a pig: case report and review of the literature

Congenital defects like myofibrillar dysplasia (splayleg), umbilical and inguinal hernias, cryptorchism, intersexes, and anal atresia occur relatively frequently in swine. On the other hand, some developmental anomalies like double monsters are very rare. The present paper reports a rare case of a congenital complex malformation including polymelia, duplicitas coli partialis et recti, atresia ani et fistula rectogenitalis, duplicitas corpori uteri, cervicis, vaginae et vulvae and duplicitas vesicae, urethrae et renalis. A plausible interpretation concerning the etiology is that the anomalies arose from unequal partial twinning. The pig has been healthy and inconspicuous. Although no anus was formed defecation took place via a fistula to one of the vaginas. Posture and behaviour of the pig were normal. Cytogenetic analysis of blood lymphocytes revealed no numerical or gross structural anomalies. There have been no further piglets with developmental disorders in the same litter, in a second litter of the same parents and in other twelve litters by the same boar.

Successful surgical correction of anal atresia in a transgenic cloned piglet

Inbred strains of pig become indispensable for a wide range of biological studies. In biomedical science, it is generally accepted that somatic cell nuclear transfer (SCNT) technology with inbreed strain of pig is essential for xenotransplantation. In this study, we observed the anal atresia in a cloned pig which was derived from fetal fibroblast of inbreed miniature pig. A presumptive anal site of the cloned pig was excised and the rectum was sutured to apposed skin for treatment. This cloned piglet seemed to be normal with healthy status after surgery. This report can be useful for the treatment of anal atresia of cloned piglets.

Incidence of splayleg pigs in Nebraska litter size selection lines1

Genetic parameters for the splayleg (SL) condition were estimated from 37,673 records of pigs from six lines derived from a Large White-Land-race base population. Random selection for 22 generations was practiced in Lines C1 and C2. Line C2 was derived from C1 at Generation 8. Selection lines were as follows: 1) Line I, selected 11 generations for an index of ovulation rate and embryonic survival followed by 11 generations of selection for litter size; 2) Line IOL, derived from Line I at Generation 8 and which underwent eight generations of two-stage selection for ovulation rate and number of fully formed pigs per litter followed by four generations of litter size selection; 3) Line COL, derived from Line C1 at Generation 8 and selected eight generations in two stages for ovulation rate and number of fully formed pigs followed by four generations of litter size selection; and 4) Line T, selected 12 generations for increased testis size. From logistic models, it was found that boars were 224% more likely to have SL than gilts (P < 0.01). Decreases in birth weight, dam age at puberty, dam nipple number, and dam embryonic survival, and increases in dam litter size and inbreeding increased the odds of SL (P < 0.05). Direct and maternal heritabilities of SL were 0.07 and 0.16, respectively, and the correlation between direct and maternal effects was -0.24. Correlations between direct genetic effects for SL and number born alive, nipple number, birth weight, age at puberty, and embryonic survival were -0.19, -0.36, 0.23, -0.19, and -0.32, respectively. Except for the correlation of 0.32 between maternal effects for SL and direct effects for number of live pigs, correlations of SL maternal genetic effects with direct genetic effects of other traits were less than 0.11. Annual direct genetic trends (%) for SL in I, IOL, COL, T, C1, and C2 were -0.003 +/- 0.003, 0.121 +/- 0.012, -0.273 +/-0.009, 0.243 +/-0.014, -0.274 +/-0.004, and 0.086 +/-0.008, respectively; annual maternal genetic trends (%) were 0.106 +/-0.004, 0.508 +/-0.019, 0.383 +/-0.015, 0.527 +/-0.024, 0.188 +/-0.005, and 0.113 +/-0.012, respectively. Annual genetic maternal trend in Line I after Generation 12 was 0.339 +/-0.014. Maternal breeding value for SL is expected to increase as a correlated response to selection for increased litter size and increased size of testes.

Deformed liver with prominent proliferation of bile ducts in a pig

A deformed liver characterized by remarkable ductular proliferation was encountered in a 6-month-old pig and examined histopathologically. The most conspicuous histopathologic change was a mild to severe ductular proliferation in the interlobular areas without any degenerative changes of cholangiolar epithelial cells or hepatocytes. Fibrotic changes and reconstruction of the lobule were not found. Morphological evidence of intrahepatic and extrahepatic cholestasis was lacking. Other characteristics were deformity with displacement of the gall bladder, irregular shape and size of lobules, and structural abnormality of large-sized vessels. The severe ductular proliferation was considered to be due to structural malformations of the excretion channel of bile.

Vitamin C plasma concentrations and leg weakness in the forelegs of growing pigs

Four litters (41 pigs) of cross-bred pigs were studied from 6 to 26 weeks of age. Blood samples were collected at 6, 13, 21 and 26 weeks of age and analysed for contents of vitamin C, calcium (Ca), inorganic phosphorus (P) and alkaline phosphatase (ALP). The pigs were examined clinically for foreleg weakness at the ages of 21 and 26 weeks. At the age of 26 weeks the pigs were slaughtered and the right forelegs were examined macroscopically and selected samples were collected for radiological, histological and ultrastructural examination. The prevalence of foreleg lesions was high, with lesions of dyschondroplasia of the distal growth plate of the ulna in 30 pigs, synovitis of the elbow joint in 24 pigs and osteochondritis dissecans of the elbow joint in 25 pigs. At the ages of 21 and 26 weeks, five pigs had evidently crooked forelegs and 14 pigs (age 21 weeks) and 25 pigs (age 26 weeks) had mildly deformed forelegs. The serum levels of Ca, P and ALP were within normal values for growing-finishing pigs. The range of vitamin C concentrations in plasma showed a wide difference (7.1-49.8 mumol/l) but was not associated with deformed forelegs. The serum concentrations of Ca, P and ALP and the plasma concentration of vitamin C differed significantly (P = 0.05) between age groups and there was a significant (P = 0.001) positive correlation between the levels of vitamin C in plasma and the serum levels of ALP at 6 weeks of age. The aim of the present study was to determine if there was any association between the plasma levels of vitamin C and the extent of crooked or deviated forelegs in growing-finishing pigs. We could not find a vitamin C deficiency during the study and no association between low levels of vitamin C in plasma and the presence of deformed forelegs of these 40 pigs.

Retarded myelination in the lumbar spinal cord of piglets born with spread-leg syndrome

Piglets born with spread-leg syndrome, a congenital weakness of the hindlimb adductors, were investigated to determine the site of lesion leading to limb impairment. Histological and immunohistochemical studies of the motor neuron unit showed no alterations but quantitative analysis revealed a reduction of axonal diameter and myelin sheath-thickness of the fibres innervating the adductors of the affected limbs. In the lumbar spinal cord a lack of myelination was observed in the tracts descending to the lower motor neurons. Recovery from the syndrome was accompanied by a catching-up of myelination with that of the controls. The spread-leg syndrome is due to a nutritional deficiency in the sow; thus it is assumed that the deficient maternal substances, mainly choline and methionine, are essential for the normal myelin production by spinal white matter oligodendrocytes of the fetus.

Surgical correction of periocular fat pad hypertrophy in pot-bellied pigs

OBJECTIVE

To report surgical correction of hypertrophic periocular fat pads that cause loss of vision and behavioral changes in pot-bellied pigs.

STUDY DESIGN

A retrospective study.

ANIMALS OR SAMPLE POPULATION

Nine Vietnamese pot-bellied pigs.

METHODS

Medical records of nine pot-bellied pigs admitted between 1994 and 1997 for loss of vision associated with hypertrophied periocular fat accumulations were reviewed. Outcome was assessed by contacting owners 4 months to 5 years after surgery.

RESULTS

The most common clinical signs were related to impaired vision and included periocular dermatitis, lethargy, and aggressive behavior. Surgical removal of redundant periorbital fat and skin resulted in marked improvement in vision and behavior in all pigs. Overall client satisfaction was excellent.

Characterization of the semen quality of postpuberal boars with spontaneous unilateral abdominal cryptorchidism on the right side

In recent studies, we found that the ectopic testis from postpuberal boars with unilateral abdominal cryptorchidism does not produce sperm. Therefore, in these males, the seminal characteristics can be used as indicators of the activity of the scrotal testis and its epididymis and also the accessory glands. The semen quality (ejaculate volume, cell-rich fraction volume, sperm concentration, sperm vitality, sperm motility, sperm morphology and cephalic stability of spermatozoa) was evaluated in healthy postpuberal boars and in postpuberal boars with unilateral abdominal cryptorchidism on the right side. In comparison with the healthy boars, the unilateral abdominal cryptorchid boars showed a significant decrease of the ejaculate volume, sperm concentration and sperm motility. The low sperm concentration indicated that unilateral abdominal cryptorchidism severely impairs the sperm production of the scrotal testis. The decrease of ejaculate volume was attributed to an abnormal activity of the accessory glands. The alterations in sperm motility develop as a result of dysfunctions in the epididymal epithelium and/or the accessory glands. The sperm vitality, sperm morphology and cephalic stability of spermatozoa maintained normal values; therefore, at testicular level, despite the low sperm production, the germ cell differentiation is not disturbed. At epididymal level, the morphological maturation of spermatozoa is not altered.

Unusual turns of the conical colon of swine

Anomalous arrangements of the conical colon were found in 38 cases out of 731 swine. These anomalies divided into the following five types: 1) additional loop running perpendicular to the turns (8 cases), 2) two or four changes in the centripetal turns (6 cases), 3) two changes in the centrifugal turns (2 cases), 4) one to three changes in both the centripetal and centrifugal turns (21 cases), and 5) two independent conical colons (1 case). The double conical colon (Type 5) was the only one case and seems to be rare. The total of the anomalous types made up approximately 5.2% and not appear to be rare.

Double gallbladder of swine

In research on the reduplication of the pig gallbladder, a total of 297,531 swine from 130 breeders were surveyed at a slaughter house (Ozu Health Center, Ehime Prefecture, Japan) between October 1993 and December 1995. The swine were 6-7 months old and their body weights ranged from 95 to 120 kg. Twenty-nine swine were found to have reduplication of the gallbladder. Of these 19 were females, nine were males and the sex of one was not identified. The second sac was smaller than main one. Eleven cases were diverticulum of a cystic duct (Type I). Diverticulum of the neck of the main gallbladder of six cases also gave rise to the second gallbladder (Type II). A sac attached to the neck of the main gallbladder via a small cystic duct in seven cases was another type of reduplication (Type III). Connection of the second sac to the middle of the hepatic duct via a small cystic duct was seen in three cases (Type IV). The positions of these small sacs to the main gallbladder were right (13 cases), left (II cases) and ventral (three cases). The fundus of one gallbladder were divided and resulted in double sacs (Type V). One second sac was set apart from the main gallbladder and attached to a hepatic duct of lateral left lobe of the liver (Type VI). One specimen of the Type III gallbladder had two additional small sacs as diverticulum of the cystic duct. Compared to occurrences in humans and the Japanese monkey, the ratio of gallbladder reduplication to normal system anatomy in swine was extremely low. It was similar to the ratio of spleen reduplication in swine (1/10,000).

Intersexuality in pigs: clinical, physiological and practical considerations

Veterinary surgeons and practical pig farmers need to be aware of a condition that can have important deleterious consequences in a breeding herd. The animals in question have sometimes been referred to as hermaphrodites but would more correctly be termed intersexes. Whilst there is a complete spectrum of phenotypic sexual development within a population of such animals, the most common form is that of a putative female with a prominent up-turned vulva. Reflection of the vulval lips reveals a much-enlarged clitoris. There may be scrotal development, in conjunction with an enlarged penile and preputial sheath. Coarse hair and incipient tusk development may further indicate differing degrees of masculinization. Surgical exploration of intersex animals confirms a complete spectrum of gonadal types, ranging from 2 ovaries with a proportion of testicular tissue in one of them (i.e., an ovotestis) to 2, much-enlarged testicular-like structures with no detectable ovarian tissue. The gonads usually remain within the abdomen, but those with testicular tissue may descend to an inguinal or even scrotal location. The genital tract invariably comprises a bicornuate uterus, a partially vestigial Fallopian tube, and some development of one or both Wolffian ducts adjoining an ovotestis or testicular-like structure to form a convoluted epididymis. Spermatozoa are never present, either in abdominal or scrotal testicular tissue, nor are there any germ cells within the seminiferous tubules, only Sertoli-like cells. Due to the spectrum of gonadal types, sexual behaviour ranges from male-type aggressivity on the one hand to regular oestrous cycles on the other, with periods of standing oestrus during which intromission may be achieved. In animals with functional ovarian tissue in both gonads, foetal development has been observed, at least until days 25-30 of gestation. Almost all intersex pigs possess XX sex chromosomes and usually 36 autosomes; only a very small proportion are chimaeras or mosaics. Chromosome banding techniques have failed to demonstrate a portion of the Y chromosome translocated onto an X chromosome nor has molecular probing revealed the presence of the sex determining gene Sry or other classical Y-related DNA sequences, except in one instance. Breeding records suggest that the intersex condition results most frequently from the influence of an autosomal recessive gene carried by certain boars. Identification of such boars is therefore essential, as the incidence of intersexuality in their offspring may reach 4-5% or more. In terms of the pig industry, economic losses may result from: 1. Lack of fertility in intersex animals. 2. Aggressive behaviour in groups of growing/fattening pigs. 3. Boar taint in the carcase of animals possessing ovotestis. 4. Propagation of the deleterious condition, either by mating or more widely by artificial insemination.

[The effect of timing of labor induction on the occurrence of congenital myofibrillar hypoplasia--short clinical report]

In an intensive pig production unit with routinely performed prostaglandin partus induction four groups of sows were formed shortly before parturition. The animals received 3 mg alfaprostol as a single intramuscular injection each. The sows of group 1 on the 112th, those of group 2 on the 113th and the animals of group 3 on the 114th day of pregnancy. Group 4 sows were not treated and formed the control group. We evaluated the number of live born piglets and the number of piglets born with congenital myofibrillar hypoplasia. The results showed no significant difference regarding live born piglets. As regards congenital myofibrillar hypoplasia the sows with early partus induction (group 1) showed significant higher incidence when compared to the other groups. It is likely that in cases of partus induction before the 113th day of pregnancy the fetus is still insufficiently protected by natural maturation, adaptation and tolerance ability against such congenital condition as CMH. Therefore it is the opinion of the authors that partus induction before the 113th day of pregnancy should not be performed.

Congenital renal glomerular fibrosis in a case of swine chondrodysplasia

A dwarf male Large White neonate showing various external abnormalities was diagnosed to be chondrodysplasia. Microscopy revealed massive accumulation of eosinophilic homogeneous substance in the renal glomeruli, mainly along the capillary walls. The homogeneous substance, mainly consisted of type-III collagen, was not found in the primitive glomeruli in the superficial cortex, and was most frequently and intensely deposited in the mature glomeruli in the deep cortex. Electron microscopically, the deposits consisted of the collagen fibrils with various structural abnormalities. Glomerular fibrosis might be attributed to in situ production of type-III collagen by glomerular cells with differentiation and maturation, most likely by the mesangial cells.

Prevalence and types of birth defects in Ontario swine determined by mail survey

Preweaning mortality in piglets constitutes a major loss to the swine industry. Congenital defects account for a small but significant proportion of these losses. To implement appropriate strategies to reduce such losses, it is necessary to identify the specific causes and their relative importance. Consequently, a mail survey of swine production in Ontario was carried out to determine the prevalence and types of birth defects. Statistical comparisons of the prevalence of overall defects were made between accurate and estimate records, breeds (cross vs. purebred), size of operation (number of sows) and geographic location. The mean litter size of 11 pigs born per sow was not significantly different for those with accurate versus estimate records, but the difference in the prevalence of defective pigs (live and dead) was significant (accurate 3.1% vs. estimate 4.1%). Splayleg (spraddleleg) was the most common defect. The next four defects for both groups were belly rupture, other rupture, ridglings and other, but not in the same ranking. Purebred and small farm operations (< 25 sows) had a significantly higher prevalence of birth defects for estimated data only. Geographic location had no effect. Further work is required to determine whether recording prevalence of birth defects in Ontario swine will provide a useful monitor of environmental stress. The study provides a baseline for the prevalence and type of defects in Ontario swine.

Congenital diseases and abnormalities of pigs

Several congenital developmental anomalies are not listed in this review because they have no proposed cause. It is the author's hope that this article will serve practicing veterinarians and the swine industry by being an informative guide for stimulating independent thought toward diagnosing congenital diseases. Remember that the cause may have exerted its effects weeks or months before being observed. A detailed history of the dam as well as the rest of the herd is important. If possible, a history of neighboring herds should also be examined for similar problems. Either conduct a thorough necropsy with appropriate tissues submitted for diagnostic analysis, or send representative pigs to a diagnostic center for a complete evaluation. If chromosome evaluation is desired, contact the evaluating laboratory for submission procedures. Breeding records should be evaluated for intragenerational frequencies and intergenerational patterns typical of genetic transmission. When evaluating pedigrees, the frequent occurrence of an individual is not proof of its involvement. The frequency of occurrence in the diseased population must be significantly greater than it is in a random population of pigs. Dr. H.W. Leipold, in the pathology department at the Kansas State University College of Veterinary Medicine, maintains an extensive database of congenital anomalies in domestic animals. I recommend that he be contacted in all cases of undiagnosed or unusual cases of congenital disease. He possibly can help with a definitive diagnosis and your contact will help expand this important central database of congenital diseases.

Congenital abnormalities of the genitalia of cattle, sheep, goats, and pigs

The essential steps in embryology of the genitalia and its sexual differentiation, are briefly reviewed. The major intersex states in domestic ruminants and pigs are briefly considered. Major attention is directed to anomalies of the reproductive organs of mature female and male animals that are likely to compromise fertility. Emphasis is placed on clinical and pathologic findings and on occurrence and pathogenesis of recorded defects.

[Development of fused vertebrae in swine]

Radiographical findings are reported on the vertebral column of healthy weanling pigs and of two pigs with connatal formation of block vertebrae and clinically visible kyphosis in the lumbar region. The diagnosis of congenital malformations of the vertebral column in two patients is based on the anamnesis, the lack of locomotor disorders and radiographic-morphologic examinations showing fusions of vertebral bodies, arches and spinous processes as well as additional dorsal hemivertebrae but no inflammatory reactions.

Blood serum characteristics of newborn pigs: comparison of unaffected pigs with pigs belonging to five mortality groups

The blood serum levels of glucose, hemoglobin, insulin, cortisol, albumin, alpha-fetoprotein, alpha 2-macroglobulin f and s, alpha 2-antitrypsin inhibitor and alpha 1-protease inhibitor were determined at birth in 5 clinically and morphologically identified mortality groups of pigs. These were compared with the levels observed in unaffected, apparently normal newborn unsuckled pigs. The blood serum profile of the pigs in the stillborn intra partum, weak, splayleg and trauma groups, respectively, as well as that of clinically normal splayleg littermates, differed significantly from that of the unaffected pigs. This was especially true for the levels of hemoglobin and the two macroglobulins. The importance of placental insufficiency causing chronic episodes of hypoxia which ultimately lead to a disturbance in organ development in the etiology of the mortality groups is discussed.

Associated multiple congenital malformations in domestic animals. Contribution of four cases

The incidence and significance of the appearance of various associated congenital malformations in a single individual have received poor attention in veterinary medicine. In this article, the malformations exhibited by four animals pertaining to three different animal species are described, and the possible reasons for the association of these anomalies are discussed from the viewpoint of the comparative medicine. All four animals showed two or three malformations constituting unrecognized teratological syndromes, so-called one-of-a-kind syndromes, which have not previously been described, at least in these particular animal species. A pig was affected by a series of craniofacial anomalies consisting in a first arch syndrome together with an occipito-parietal meningocele. Another member of the porcine species showed holoprosencephaly with cyclopia, various defects in the left forelimb and an extensive omphalocele. A dicephalic cat with cervical rachischisis and myeloschisis and a dog exhibiting spina bifida, curled tail and atresia ani are also described.

[The content of ascorbic acids in different tissues of cattle, normally developed piglets, splay-legged piglets, adult swine and dogs]

The following ascorbic acid levels were recorded from different organs of cattle, with all values quoted being related to mg/100 g fresh matter: 150 +/- 20 in pituitary gland, 170 +/- 40 in left adrenal gland, 45.5 +/- 12.5 in spleen, 38.1 +/- 7.3 in liver, 30.0 +/- 8.5 in cerebrum, 23.2 +/- 7.2 in cerebellum, 16.4 +/- 6.1 in kidney, 11.0 +/- 2.9 in heart, and 9.1 +/- 2.1 in M. longissimus dorsi. The ascorbic acid level in blood plasma of normally developed piglets was 6.5 +/- 2.7 mg/dl and was thus higher with significance (p less than 0.01) than that recorded from splayleg piglets which was 2.3 +/- 0.96 mg/dl. The levels in the M. semimembranosus and M. semitendinosus in piglets of moderate birth weight were higher, as well (p less than 0.05). The liver level in pigs for slaughter was 30.8 +/- 9.0 mg/100 g lower than that in piglets. Piglets exhibited genetically founded differences in their capability of biosynthesis of ascorbic acid. The highest ascorbic acid level in dog was recorded from the pituitary and adrenal glands, values being 135.5 +/- 7.5 mg/100 g fresh matter or 90.3 +/- 37.8 mg/100 g. Their liver level was 27.9 +/- 11.9 mg/100 g.

Myocardial bridges in animals

Myocardial bridges in a number of different species is described and classified. In formulation of the classification special attention was given to the location, width, thickness of the muscular layer of the bridge and the number of commitant veins of the overbridged artery. Four types of myocardial bridges were recognized.

Renal dysplasia in a pig

A diagnosis of renal dysplasia was made in a six-month-old, male, mixed-breed pig. Both kidneys were small, firm, slightly pitted, and contained an indistinct corticomedullary junction. Histologically, primitive tubules were present surrounded by an abundant loose, mesenchymatous stroma. Occasionally, tubules were markedly dilated and lined by a pseudostratified columnar epithelium forming epithelial mats that obscured the lumina. Immature glomeruli were present. Multifocal glomerular sclerosis was evident. Other mature glomeruli were enlarged and characterized by mesangial cell hyperplasia forming an arborizing pattern.