Tail-biting in outdoor pig production

A study was performed in five identical outdoor production units in the same geographic area using growing-finishing pigs of similar genetic makeup, age, diet and feed management. The severity of tail-biting (TS) was scored 1-4. The average group prevalence of bitten tails at slaughter on different farms was between 14.1+/-2.1% and 20.1+/-3.0% (P<0.05). The odds of a barrow being bitten were 2.9 times higher than those for a gilt. The most frequently recorded score of bitten tails was TS3, indicating moderate wounds with low grade infection. The prevalence of bitten barrows was positively correlated with the percentage of gilts in a group (r = 0.54, P<0.001). Pigs with zero TS score had no significantly higher weights at slaughter compared to pigs with a score of TS1. As the TS increased from 1 to 4, weights decreased (TS 1 to TS 2 to 4, P<0.05). TS 3 and 4 were positively (P<0.001) associated with subsequent carcass condemnation. We concluded that outdoor rearing does not prevent tail-biting.     

Porcine circovirus as a possible cause of postweaning wasting in pigs in Switzerland

Postweaning wasting is a major worldwide problem in pig production, particularly with respect to the disease termed postweaning multisystemic wasting syndrome (PMWS). In addition to wasting, PMWS symptoms include respiratory distress, diarrhoea, pallor and occasional cases of jaundice. The causative agent is porcine circovirus type 2 (PCV-2). The objective of the present study was to determine the significance of PMWS and similar conditions in Switzerland. A total of 72 weaned piglets from 26 farms showing wasting were examined for the presence of PCV-2 by immunohistochemical and histological analysis and 57 piglets from 21 farms were examined serologically. Possible causes for wasting other than PCV-2 were investigated by macroscopic, histological and bacteriological methods. PCV-2 antigen was identified immunohistochemically in the lymphatic organs in 11 of these 72 piglets. However, only 4 animals showed histological changes typical of PMWS. PCV-2 antibodies were found in 70% of the piglets. Piglets with wasting syndrome not associated with PCV-2 infection suffered from conditions including porcine proliferative enteropathy, gastric ulcers, polyserositis and polyarthritis. The most frequent condition was chronic enteritis not associated to circovirus infection. The results from the serological analyses indicate a wide distribution of PCV-2 in the Swiss pig population. However, confirmed cases of PMWS were rare in the investigated piglets.     

Cryptorchidism and sex ratio are associated in dogs and pigs

The objective of this study was to investigate whether the occurrence of cryptorchidism in a litter is associated with the sex ratio in this litter. The analysis included for dog 1,339 litters of 4 different breeds, of which 12.8% had 1 and 3.1% had 2 cryptorchids, and for pig 119,920 litters of 14 different populations, of which 2.2% had 1 and 0.2% had 2 cryptorchids. The data were analyzed using the GLIMMIX procedure of SAS. In dog, the presence of cryptorchids in a litter does not affect litter size or the stillborn rate. In pig, litter size increases significantly with an increasing number of cryptorchids in a litter. The stillborn rate in pig is larger in litters with cryptorchids than in litters without cryptorchids. To characterize the imbalance of the sexes in a litter, the sex ratio, defined as the number of live males divided by the number of live offspring, and the sex difference, defined as the number of live males minus the number of live females, were used as dependent variables in the analyses. In both dog and pig, the presence of 1 or 2 cryptorchids in a litter clearly goes together with a shift in both the sex ratio and the sex difference in a litter, in favor of male offspring. Our results in dog and pig suggest a common underlying mechanism affecting both cryptorchidism and sex ratio, which may hold true in other mammals as well.     

Effects of cadmium on serum sex hormone levels in pigs

An inhibition of sex hormone secretion is observed in domestic animals exposed to cadmium in experimental conditions. Ninety-six gilts (Duroc x Landrace x Yorkshire, initial weight 27.59 kg) were randomly assigned into four different groups with three replications in each group (eight gilts per replication). The groups received the corn-soybean basal diet and supplemented with 0, 0.5, 5.0 and 10.0 mg/kg cadmium (as CdCl2) respectively. The feeding trial was ended when body weight of pigs was approximately 90 kg. The results showed that 10.0 mg/kg cadmium significantly decreased average daily gain (p < 0.05) and increased feed/gain ratio (p < 0.05) of pigs. Follicle-stimulating hormone, luteinizing hormone, oestradiol (E2) and progesterone levels in serum of the pigs fed the diet supplemented with 10.0 mg/kg cadmium were lower significantly than those of the control (p < 0.05). Compared with the control, no changes were found in the levels mentioned above when the pigs fed the diet supplemented with 0.5 or 5.0 mg/kg cadmium (p > 0.05). The changes of regulatory mechanism of the pituitary-ovary axis may be the result of cadmium accumulation in pituitary and ovary and should be investigated further.     

Observations on the incidence of Ascaris lumbricoides in New Zealand pigs

Extract

It is often considered that Ascaris lumbricoides is one of the most common parasites of pigs and also one of the most serious. There is no doubt that this is so in many parts of the world but until recently there was little information available on its importance in New Zealand. It is well recognized that the parasite is pathogenic for pigs, particularly for younger pigs and during the period when the worms are immature and undergoing their migration through the lung tissue.     

Reproductive and neonatal losses associated with possible encephalomyocarditis virus infection in pigs

A possible infection with encephalomyocarditis virus was investigated on two Minnesota pig farms which experienced an increase in stillborn and mummified fetuses, high pre-weaning mortality and reduced farrowing rates. The monthly averages for the numbers of piglets born dead per litter on farms A and B reached 4-6 and 3-6, the pre-weaning mortalities 50 per cent and 31 per cent, and the farrowing rates 52 per cent and 63 per cent, respectively. Serological and histopathological examinations supported a diagnosis of infection with encephalomyocarditis virus, but attempts to isolate the virus failed. Specific antibody to the virus was detected in both fetal and neonatal sera collected from abnormal litters. The predominant histopathological finding was myocarditis consisting of focal or diffuse mononuclear cell infiltration. The detection of specific antibody, and the myocardial lesions in stillborn fetuses, suggested that the problems were associated with infection by encephalomyocarditis virus.     

Metabolic utilization of energy and maintenance requirements in growing pigs: effects of sex and genotype.

An experiment was conducted in which the metabolic utilization of energy was measured in individually penned pigs from seven groups that differed in genotype and(or) sex and ranged in body weight between 20 and 107 kg. The animals were fed a diet containing, on a DM basis, 14.7 MJ ME and at least 21% CP. Heat production was measured in an open-circuit calorimeter, and energy, nitrogen, and fat balances were determined at regular intervals over the growing period; a total of 177 measurements were performed. Body composition of the animals was measured by serial slaughter, and these data were used for estimating the body composition of an animal at a given weight through allometric regression. A factorial analysis procedure was used to estimate the utilization of ME by regressing the ME intake on the observed protein and lipid deposition rates. The intercept of this equation is the maintenance energy requirement (MEm) and was represented either as a function of body weight with group-specific parameters (MEm = a(i) BWb) or as a function of the muscle and visceral mass with an additional additive group effect (MEm = aM muscle(b) + a(v) viscera(b) + G(i)). With BW as dependent variable, the exponent b was close to .60 and differed significantly from .75. The regression coefficient (a(i)) averaged 1.02 MJ ME/kg.60 but it was different for most groups, indicating that different groups of animals have different maintenance requirements. Fixing the exponent to .75 consistently underestimated the maintenance requirement. When the exponent b was not fixed to .75 but estimated, the partial efficiencies for protein and lipid deposition were .62 and .84, respectively. Body muscle and visceral mass could explain a large part of the variation in MEm. Viscera contributed three times more to MEm (per kilogram of mass raised to the .70 power) than did muscle. Even though the muscle mass exceeds to a large extent the visceral mass in animals, the contribution of muscle to MEm was lower than that of viscera for most groups.     

Cryptosporidiosis in guinea pigs: a retrospective study

Cryptosporidiosis was diagnosed in 81 guinea pigs (Cavia porcellus) from 1979 through 1985 at a research animal diagnostic laboratory. Most of the guinea pigs were juveniles of Hartley stock and originated from 6 commercial laboratory animal suppliers or from one pet store supplier. Common clinical signs reported were failure to gain weight, weight loss, diarrhea, and death. At necropsy, macroscopic findings included emaciation, hyperemia of the small intestine, serosal edema of the cecal wall, and increased fluidity of ingesta throughout the intestines. Oval to round cryptosporidia (1 to 4 microns) were seen microscopically within or on the brush border of mucosal epithelial cells from the duodenum through the cecum. Acute histologic lesions consisted of necrosis and sloughing of enterocytes at the villus tips, inflammation, hyperemia and edema of the lamina propria, and hyperplasia of crypt epithelium. More chronic lesions consisted of marked villus bridging or villus fusion and blunting, metaplasia of the mucosal epithelium, and lymphocytic infiltration of the lamina propria.     

Coarctatio aortae in pigs: a morphological approach

Two types of coarctatio aortae in pigs are described. In the juvenile type the, funnel-shaped, narrowing in the arcus aortae was located between the origin of the a. subclavia sinistra and the aortic end of the ductus arteriosus or ligamentum arteriosum. Until now, this type has been observed only in animals with other heart anomalies. In the adult type, the narrowing of the arcus aortae was crescent-shaped and was located at the aortic end of the ductus arteriosus or ligamentum arteriosum. Histologic examination of parts of the funnel-shaped and the crescent-shaped narrowing revealed that the two types of coarctatio aortae develop differently.     

The incidence of Leptospira hyos and Leptospira pomona infections in pigs in New Zealand

Extract

The occurrence of leptospirosis in New Zealand was first reported by this station in 1950. when Leptospira pornona was isolated from a calf with haemoglobinuria. Since then it has been demonstrated in most farm animals, including pigs, on many occasions.     

Pneumonia of pigs: a review

Pneumonia of pigs is one of the more important disease factors limiting pig production. Of the varieties of pneumonia affecting this species enzootic pneumonia caused by Mycoplasma spp. is the most common and most important. The major effects of this disease are lowered food conversion ratio and poor weight gain. Deaths are usually the result of secondary infection by necrotising, pus-forming bacteria. Eradication of the disease is expensive and requires depopulation and restocking. Control and treatment by antimicrobial agents is most effective if the drug combination used takes regard of the bacteria complicating the disease on any particular property. Other forms of pneumonia such as those caused by Haemophilus pleuropneumoniae, Salmonella cholerae-suis and Aujeszky's disease virus can be important on individual farms. The role of other agents such as Bordetella bronchiseptica and adenoviruses in respiratory disease of pigs remain to be clarified.     

Pneumonia of pigs: a review

Pneumonia of pigs is one of the more important disease factors limiting pig production. Of the varieties of pneumonia affecting this species enzootic pneumonia caused by Mycoplasma spp. is the most common and most important. The major effects of this disease are lowered food conversion ratio and poor weight gain. Deaths are usually the result of secondary infection by necrotising, pus-forming bacteria. Eradication of the disease is expensive and requires depopulation and restocking. Control and treatment by antimicrobial agents is most effective if the drug combination used takes regard of the bacteria complicating the disease on any particular property. Other forms of pneumonia such as those caused by Haemophilus pleuropneumoniae, Salmonella cholerae-suis and Aujeszky’s disease virus can be important on individual farms. The role of other agents such as Bordetella bronchiseptica and adenoviruses in respiratory disease of pigs remain to be clarified.