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Serum samples collected from feral swine (Sus scrofa) throughout Florida (USA) from 1974 to 1989 were tested for antibodies to Brucella sp. by the card test, the standard tube test, the rivanol test or the complement fixation test. Seropositive swine were detected at six of 18 sites with a composite prevalence of 23.4% (238 of 1,015 samples; range = 5.5% to 33.3%) for sites with seropositive swine. At one site for which age and sex data were available there was no significant difference (P = 0.50) in seroprevalence between males and females. Antibody prevalence in adult (or = 8 mo) and juvenile swine (8 mo), however, was significantly different (P0.05). Based on these data, Brucella sp. infections are limited only to certain populations of feral swine. To avoid the spread of Brucella sp. organisms, however, relocation of feral swine is not recommended.

Serum samples collected from feral swine (Sus scrofa) throughout Florida (USA) from 1980 to 1989 were tested for antibodies to pseudorabies virus (PRV) by the serum neutralization test, the latex agglutination test, or by the enzyme-linked immunosorbent assay. Seropositive swine were detected at 11 of 13 sites with a composite seroprevalence of 34.8% (579 of 1,662 samples; range = 5.9% to 58.2%) for sites with seropositive swine. Data on age and sex of the swine were available from three sites. Seroprevalence in males and females did not differ significantly (P = 0.62 for the combined data). Seroprevalence in adult (or = 8 mo) and juvenile swine (8 mo) was significantly different at all sites (P0.05 for the combined data). From these data, PRV infections appear to occur widely in populations of Florida feral swine and may seriously undermine efforts to eradicate this virus from the domestic swine population of the USA.

Three experiments were conducted to compare sugarcane condensed molasses solubles (CMS), sugarcane molasses or a CMS—molasses mixture as ingredients in steer finishing diets, and to determine the effect of monensin in combination with CMS on ruminal volatile fatty acid production. In Experiments 1 and 2, 40 yearling steers were fed on a dry basis 0 or 5% CMS, 5% molasses or 5% of a CMS—molasses mixture (50% w/w fresh basis) for 67 and 96 days, respectively. Steers in Experiment 2 were all fed 33 g/metric ton of monensin. Average daily gain and dry feed conversion rate were, respectively, 0.89 kg and 9.61 in Experiment 1, and 1.28 kg and 6.14 in Experiment 2, with no differences among treatments. There were no treatment effects on carcass characteristics. Experiment 3 was a 2 × 2 factorial arrangement with 0 or 33 g monensin/metric ton fed to 40 yearling beef steers, in combination with 0 or 10% CMS (dry basis), for 134 days. In Experiment 3, 10% CMS decreased gain (P

Perfusion studies in swine with early lesions of osteochondrosis demonstrated that lamellar areas of chondrocyte necrosis within reserve zones of growth areas occurred only in regions of nonperfused articular cartilage. Articular cartilage with a similar anatomical location was perfused in some animals. Occasionally, nonperfused articular cartilage showed vascular alterations within cartilage canals without evidence of significant perivascular or lamellar necrosis. By light microscopy, some vessels within or adjacent to nonperfused articular cartilage had normal morphology; however, ultrastructural abnormalities were found in some vessels of all cartilage canals adjacent to necrotic cartilage lamella. Minimal alterations were in the few cartilage canal vessels that appeared normal by light microscopy, and the surrounding chondrocytes showed only minimal alterations. Early cartilage canal alterations were seen in the endothelium of cartilage canal capillaries, and ultrastructural changes in these vessels were similar to those described with experimentally induced, direct vascular injury. Vascular injury was followed by leakage of plasma and cells into the interstitial space of the cartilage canal. Necrosis of the vessel wall and interstitial tissue caused the cartilage canals to appear empty or to be filled with fibrin-like material. Although the vascular changes could be considered as part of the normal process of cartilage maturation and cartilage canal chondrification, observations suggest that in domestic swine the attendant cartilage necrosis and chondrolysis is exuberant. It is suggested that alterations in cartilage canal vessels play a major role in the pathogenesis of articular cartilage lesions that are found in osteochondrosis of swine.

Ivermectin (300 micrograms/kg of body weight) was given to swine subcutaneously in the neck to test its efficacy against the kidney worm, Stephanurus dentatus. Two separate field trials were conducted using 146 swine (40 males and 106 females). Urine was obtained before and after treatment and was examined for presence of S dentatus eggs. Stephanurus dentatus eggs were quantitated in positive samples. All treated swine positive for S dentatus eggs in the pretreatment urine samples (n = 54) were negative by 14 to 21 days after treatment with ivermectin. Adverse reactions caused by ivermectin injection were not noticed.

Weanling gilts were fed either a 12% or 16% protein diet for 10 weeks. Animals fed the 12% protein diet had reduced body weights and reduced longitudinal bone growth as measured in the distal radial growth plate. There was no difference in the growth plate widths between the two animal groups, but there was a significant reduction in the daily rate of cell production in the proliferative zone of animals fed the 12% protein diet. No effect of diet on the rate of expansion of the epiphysis at the articular-epiphyseal junction of the distal femur or humerus could be detected. All animals in both groups had morphologic cartilage lesions consistent with early changes associated with osteochondrosis (OCD), and there was no difference in the lesion morphology between the dietary groups. Areas of disorderly endochondral ossification in the radial growth plate were associated with perpendicular growth cartilage infractions. Growth plate lesions were characterized by increased widths of the maturing cartilage zone without increased width of the proliferative zone or an increase in the daily rate of cell production. Focal growth plate lesions developed because of a transitory inhibition of cartilage mineralization and resorption. Disorderly foci of endochondral ossification beneath articular cartilage were characterized by an area of chondrocyte necrosis which prevented normal cartilage matrix mineralization. Lamellae of cartilage necrosis were also present within the reserve zone of the articular cartilage. These were associated with abnormalities of the cartilage canal vessels, and chondrocyte necrosis was considered to precede degenerative changes in articular cartilage matrix. Since similar changes were rarely seen in the distal metacarpal (tarsal) bones of the dew claws, endogenous trauma was considered an important factor in lesion pathogenesis. The possibility that a basic cartilage matrix abnormality might represent the primary cause of OCD is discussed.

Serums from 95 feral swine trapped in Glades County, Florida, were tested for brucella antibodies, using the standard tube, card, rivanol, and complement-fixation tests. Fifty (53%) of the animals were seropositive to at least 1 test. The standard tube test detected 98% of the serums positive to any of the 4 procedures. The prevalence of brucella antibodies was significantly lower (P less than 0.0005) in feral swine less than 6 months old than in those greater than or equal to 6 months old. The prevalences by sex were similar. Necropsies were performed on 9 of the feral swine. Brucella suis, biotype 1, was recovered from all 9, with lymph nodes being the tissues most commonly infected. Only the standard tube test detected brucella antibodies in all 9 culture-positive animals.

Feral pigs trapped in Florida were exposed by intranasal/oral inoculation or contact to African swine fever virus isolants from the Iberian peninsula and the Dominican Republic. All exposed pigs became sick and died or were killed after becoming moribund. Necropsy revealed lesions typical of African swine fever, but several pigs had marked hemorrhage surrounding the kidneys or rectum or in the gastric, hepatic, or ventral abdominal region that, in the field, might have suggested trauma or poisoning as a cause of death. Most pigs had severe lesions associated with kidney worms. Virus was detected in the blood and selected tissues of each pig, using the hemadsorption reaction in porcine monocyte cultures; direct or indirect immunofluorescence was used to confirm the diagnosis.

The anthelmintic spectrum of activity and efficacy of flubendazole, using pigs naturally infected with helminth parasites, were determined in 4 experiments, using 157 pigs. Flubendazole (1.5 mg/kg of body weight) mixed in feed or top-dressed on feed for 5 consecutive days was highly effective as an anthelmintic. This dosage level indicated 100% efficacy against mature Ascaris suum, Oesophagostomum dentatum, Trichuris suis, and Metastrongylus apri. There was 88% efficacy against Strongyloides ransomi and 85% efficacy against Stephanurus dentatus and immature Ascaris suum. There was some activity against Globocephalus sp and Macracanthorhynchus hirudinaceus, but insufficient numbers of these parasites were present to make an accurate assessment.

Changes in mammary gland histology, dry weights, nucleic acids and in vitro rates of substrate oxidation in incorporation into lipid were measured in mammary biopsies of three gilts each on d 30, 45, 60, 75, 90, 105 and 112 of pregnancy, and d 1 and 4 of lactation. Histological changes noted were progressive duct growth early in pregnancy followed by rapid lobulo-alveolar development between d 75 and 90 to complete mammogenesis. Colostrum and lipid were evident by d 105 with marked distension of alveolar lumina on d 112. Complete differentiation of the secretory process was apparent on the day of parturition. Concentrtion of dry, fat-free tissue (DFFT) and DNA changed little before d 60 but increased fourfold between d 75 and 90. No further increases in DFFT or DNA were noted. RNA concentrations paralleled DNA through d 90, after which they steadily increased. Rates of acetate and glucose oxidation increased transiently during midpregnancy then declined and remained low until initiation of lactogenesis. Substrate incorporation into lipid increased slightly at midpregnancy and again at d 105, after which it increased markedly. Collectively, results indicate that mammogenesis is complete by d 90, after which lactogenesis is initiated in a two-stage process. Metabolic rates expressed on a DNA basis indicated considerable rates of oxidation, but not of lipogenesis by proliferating mammary tissue. Preferential metabolism of acetate vs glucose near parturition suggests coordination of metabolism between the mammary gland and other maternal tissues.