An effective way of preventing undesirable boar taint in pork meat caused by the presence of androstenone, skatole and indole is surgical castration of piglets. This, however, arouses growing social opposition. An alternative method of inhibiting the development of unpleasant odour is immune castration. The aim of the study was to compare the effectiveness of both methods of castration for the elimination of the compounds responsible and to assess the suitability of oral fluid for pre-slaughter predictive testing for boar taint. The research material was pooled oral fluid and fat samples taken from gilts and surgically and immunologically castrated piglets. The samples were tested with a liquid chromatography– tandem mass spectrometry method developed in this research. The compounds giving rise to boar taint were found only sporadically above the accepted limits; only one sample of oral fluid contained skatole at a concentration above 200 μg L⁻¹ and one contained indole more concentrated than 100 μg L⁻¹. Indole above the limit value was also detected in one fat sample. In none of the tested samples was androstenone found. The results indicate the similar effectiveness of both methods of piglet castration on the reduction of compounds generating boar taint. The usefulness of testing oral fluid for the ante-mortem prediction of boar taint has not been fully confirmed and further investigation is needed.

Porcine reproductive and respiratory syndrome virus (PRRSV) can be devastating to commercial breeding operations. The objective of this study was to evaluate a novel European PRRSV vaccinal strain for safety and efficacy in bred gilts. In 2 experiments, 110 gilts were vaccinated intramuscularly and the vaccine was evaluated for safety and efficacy. Gilts in Experiment 1 were evaluated for local and systemic reactions and gilts in both experiments were observed for clinical signs of disease through farrow. In both experiments, piglet clinical observations, piglet average daily weight gain (ADWG), gilt serology [determined by enzyme-linked immunosorbent assay (ELISA)], gilt and piglet viremia [determined by quantitative real-time polymerase chain reaction (qPCR)], as well as piglet lung lesion scores and PRRS virus in lung tissue (qPCR) were determined. The vaccine was shown to be safe as there were no significant differences among groups in either experiment. Efficacy was established in Experiment 2 as both vaccinated groups were associated with desirable significant differences in percentage of gilts with abnormal clinical findings; gilt viral load post-challenge [day 125, day of farrowing (DOF), and DOF + 13]; percentages of alive, healthy live, weak live, and mummified piglets per litter at farrowing and weaning; percentage of piglets per gilt that were positive for viremia; percentage of piglets per gilt with clinical disease; and piglet viral load on DOF. It was concluded that a vaccine formulated from the PRRSV modified live virus (MLV) strain 94881 is a safe and effective method of protection against the detrimental effects of virulent PRRSV infection in breeding female pigs.

The objective of this study was to determine the effect of additional human chorionic gonadotrophin (hCG) on the ovarian response of gilts previously treated with 200 IU hCG combined with 400 IU equine chorionic gonadotrophin (eCG) (eCG/hCG). Seventy-one prepuberal gilts (105 ± 7.5 kg) were assigned to groups: i) eCG/hCG (hCG-0; n = 25); ii) eCG/hCG followed by 100 IU of hCG at 24 h (hCG-100; n = 24); iii) eCG/hCG followed by 200 IU hCG at 24 h (hCG-200; n = 10); and iv) controls (CON; n = 12). Ovulation response was assessed by ovarian dissection or real-time ultrasonography. Additional hCG did not significantly improve numbers of gilts ovulating. Numbers of corpora lutea increased with hCG, and was higher in hCG-200 (P < 0.01). Compared to hCG-0, the frequency of cysts in gilts was higher in hCG-100 (P < 0.05) and further increased in hCG-200 (P < 0.01). The number of cysts per gilt was dose-dependently increased by additional hCG. We conclude that supplemental hCG will increase the number of corpora lutea but will be associated with follicular cyst development in a dose dependent manner.

Healthy gilts and market-ready hogs were administered a single intramuscular (IM) injection of Borgal, a commercial formulation of trimethoprim-sulfadoxine (TMP-SDX), once or twice daily. The objectives were to determine if a newly-developed high-performance liquid chromatographic (HPLC) method would be suitable for measuring the residual concentrations of TMP in the plasma of these live animals, and to determine if the administration of this veterinary drug would leave measurable residues in their plasma and tissues at slaughter. Plasma and tissue concentrations of SDX and TMP from these animals were determined over a period of 14 d using thin-layer chromatography/densitometry (TLCD), and the newly-developed HPLC method, respectively. The lowest detectable limit (LDL) for SDX in plasma and tissue was 20 ppb by TLCD. The HPLC method had a LDL of 5 ppb for TMP in plasma and tissue. Both methods were then used to provide baseline data on the absorption and depletion of TMP and SDX from these healthy animals. It was observed that both TMP and SDX were readily absorbed into the blood and tissues, but TMP was eliminated much faster than SDX. No TMP residues were detected in the plasma of any of the gilts at and beyond 21 h after drug administration. Also, no TMP residues were detected in the plasma of any of the market-ready hogs 24 h after drug administration at either the label dose or twice the label dose. Sulfadoxine residues at concentrations above the maximum residue limit (MRL) of 100 ppb were, however, detected in the plasma, muscle, kidney, liver, and injection sites of hogs slaughtered 1 and 3 d after a single IM administration at the label dose. Although SDX residues were still detectable in the lungs, kidney, liver and plasma of some hogs 10 d after administration of the label dose and twice the label dose, these were below the MRL. Postmortem examination revealed necrosis and inflammation at the injection sites, but no visible deposits of the injected drug.

The effects of short-term restraint stress, by means of snaring, on plasma concentrations of catecholamines, beta-endorphin, and cortisol were studied in 6 gilts. A catheter was inserted into the jugular vein, and 2 blood samples were collected before onset of stress. Thereafter, a hog snare was applied, and blood samples were collected at 0.5, 2, and 3.5 minutes after the start of snaring. Plasma epinephrine and norepinephrine concentrations increased (P < 0.001) within 0.5 minute after start of restraint and decreased thereafter. Plasma concentration of beta-endorphin increased (P < 0.05) within 2 minutes after start of restraint, whereas that of cortisol increased (P < 0.05) 3.5 minutes after start of restraint. Taken together, short-term stress, such as snaring, may increase the plasma concentration of catecholamines, beta-endorphin, and cortisol in pigs.

The effect of mimicking prepartum concentration of estradiol-17 beta on the inflammatory response to endotoxin in gilts was studied. The study was performed in a split-litter design and comprised 5 pairs of littermates. A catheter was inserted into the jugular vein 2 days prior to the start of the study. In each pair, 1 littermate was treated IM with 2.5 mg of estradiol-17 beta/75 kg of body weight, and the other littermate was given peanut oil IM as a control. The day after treatment, all gilts were challenge-exposed with a Salmonella typhimurium-derived endotoxin (1 microgram/kg, IV) and the inflammatory response to challenge exposure was monitored. There was no effect of estradiol treatment on the transient clinical signs of endotoxemia or on the increase in rectal temperature. The increase in blood concentrations of prostaglandin F2 alpha, metabolite and cortisol after endotoxin challenge exposure was not affected by estradiol. Decrease in number of circulating blood mononuclear cells and polymorphonuclear leukocytes was not changed by estradiol treatment. Taken together, mimicking prepartum concentration of estradiol did not affect either the magnitude or the kinetics of the inflammatory response to endotoxin in gilts. Relevance of these findings to development of endotoxin-mediated diseases, such as the postpartum agalactia syndrome, needs further study.

Ochratoxin A (OA) was incorporated in the diets of growing gilts (mean body weight, 20.1 kg) at a concentration of 2.5 mg of OA/kg of feed and was fed continuously for 35 days. Humoral and cell-mediated immunologic measurements were evaluated to determine the effects of OA on immune function in swine. Cutaneous basophil hypersensitivity to phytohemagglutinin (PHA), delayed hypersensitivity to tuberculin, PHA-induced lymphocyte blastogenesis, interleukin-2 production, total and isotype immunoglobulin concentrations, antibody response to chicken RBC, and macrophage activation were used to evaluate immune function. Gilts treated with OA had reduced cutaneous basophil hypersensitivity response to PHA reduced delayed hypersensitivity to tuberculin, decreased stimulation index for lymphoblastogenesis, decreased interleukin-2 production when lymphocytes were stimulated with concanavalin A, and decreased number and phagocytic activity of macrophages. Differences were not observed for total and isotype immunoglobulin concentrations, or humoral hemagglutination (chicken RBC) titer. These data indicate that OA may suppress cell-mediated immune response in growing swine.

Specimens of the uterine tube epithelium (ampulla) were obtained from 20 healthy, prepubertal, ovariohysterectomized gilts. A 2 to 3% proportion of atypical cilia was observed. Of 6,600 transversely sectioned cilia, 122 (1.8%) had microtubular disorganization, whereas 444 of 48,080 totally examined cilia (0.9%) were compound, 104 (0.2%) were swollen, and 44 (0.09%) were intracytoplasmic.

A corn culture of Fusarium roseum was added to a standard corn-soybean swine gestation ration. Low, middle, and high dosage mixed feeds contained 7, 38, and 64 mg of zearalenone/kg of feed (7, 38, and 64 ppm) and 0.5, 2.5, and 4.5 mg of deoxynivalenol/kg, respectively. Control feed was the standard ration without added F roseum corn culture. Mature gilts were bred by natural service and fed control or F roseum molded feed from 3 to 34 days after breeding. The main effect of the molded feed was an inhibition of fetal development, with decreased numbers of fetuses present in treated animals at slaughter (38 to 43 days after breeding). Normal litters were present in 7 of 8 control animals, in 2 of 4 gilts given the low-dosage feed, in 1 of 4 gilts given the medium dosage, and in 0 of 4 given the high-dosage feed. Corpora lutea were maintained in all treated animals, as evidenced by serum progesterone concentrations. Serum estradiol concentrations were decreased in gilts in the middle- and high-dosage groups. The genital system of the gilts fed low- and middle-dosage feeds had a gross and microscopic appearance similar to that of the pregnant controls and reflected prolonged progesterone stimulation. Morphologic changes in the genital system of the high-dosage group were intermediate between changes induced by progesterone and those induced by estrogen. Clinical signs of hyperestrogenism and partial feed refusal were noticed in only some of the high-dosage group animals.

Objective-To use mathematical modeling to assess the effectiveness of control strategies for porcine reproductive and respiratory syndrome (PRRS) virus on a swine farm. Sample-A hypothetical small, medium, or large farrow-to-weaning swine farm in the Midwestern United States. Procedures-Stochastic models were formulated to simulate an outbreak of PRRS on a farm. Control strategies assessed in those models included none (baseline) and various combinations of mass immunization, herd closure, and gilt acclimatization. Nine different models resulting from the combination of low, moderate, or high PRRS virus virulence and small, medium, or large herd size were simulated. A stabilized status, the outcome of interest, was defined as the absence of positive PCR assay results for PRRS virus in 3-week-old piglets. For each scenario, the percentage of simulations with a stabilized status was used as a proxy for the probability of disease control. Results-Increasing PRRS virus virulence and herd size were negatively associated with the probability of achieving a stabilized status. Repeated mass immunization with herd closure or gilt acclimitization was a better alternative than was single mass immunization for disease control within a farm. Conclusions and Clinical Relevance-Repeated mass immunization with a PRRS modified-live virus vaccine with herd closure or gilt acclimitization was the scenario most likely to achieve a stabilized status. Estimation of the cost of various PRRS control strategies is necessary.