Relationships among treatment for respiratory tract disease, pulmonary lesions evident at slaughter, and rate of weight gain in feedlot cattle.

OBJECTIVE: To quantify the effects of treatment for clinical respiratory tract disease and pulmonary lesions identified at slaughter on rate of weight gain in feedlot cattle. DESIGN: Prospective longitudinal study. ANIMALS: 469 feedlot steers. PROCEDURE: Clinical respiratory tract disease was monitored between birth and slaughter. Steers were weaned at approximately 6 months old and entered into the feedlot for a mean of 273 days. Mean daily weight gain (MDG) was monitored during the feeding period. Lungs were collected at slaughter and evaluated for gross lesions indicative of active or resolved pneumonia. RESULTS: Mean daily weight gain during the feeding period was 1.30 kg, and ranged from 1.16 to 1.46 kg within individual pens. Thirty-five percent of steers received treatment for respiratory tract disease between birth and slaughter, whereas 72% had pulmonary lesions evident at slaughter. Among steers treated for clinical respiratory tract disease, 78% had pulmonary lesions, whereas 68% of untreated steers had pulmonary lesions. Pulmonary lesions at slaughter were associated (P < 0.01) with a 0.076-kg reduction in MDG during the feeding period. Treatment for clinical disease was not associated with MDG after adjustment for the effect of pulmonary lesions. CLINICAL IMPLICATIONS: Treatment of clinically affected feedlot cattle may be inadequate to prevent significant production losses attributable to respiratory tract disease.

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.

Serum gamma-glutamyltransferase activity and protein concentration at birth and after suckling in calves with adequate and inadequate passive transfer of immunoglobulin G.

In an effort to characterize the activity of serum gamma-glutamyltransferase (GGT) in newborn calves before and after suckling and to explore the usefulness of serum GGT as an indicator of failure of passive transfer in calves, blood samples were collected from the first calves of 48 cows at the time of birth and at 1 day of age. Serum was harvested, and concentrations of IgG and protein and activity of GGT were determined. Morbidity and mortality events were monitored from birth to weaning. Calves suckling colostrum had 10 and 1.3 times greater serum concentrations of IgG and protein, respectively, and a 26 times greater serum activity of GGT, compared with concentrations at birth. Increases in GGT activity and protein concentration were correlated to increases in IgG concentration. Calves classified as having failure of passive transfer (< 800 mg of IgG/dl) had a 9.5 times greater risk of becoming sick prior to weaning, compared with calves determined to have partial failure of passive transfer and clinically normal calves (P = 0.0004). The sensitivity and specificity of a cutoff value of 200 IU of GGT/L of serum for diagnosing failure of passive transfer were 80 and 97%, respectively. The sensitivity and specificity of a cutoff value of 4.2 g of protein/dl serum for diagnosing failure of passive transfer were 80 and 100%, respectively. The Kappa values for diagnosis of failure of passive transfer, using serum concentrations of IgG vs activity of GGT, IgG vs protein, and GGT vs protein, were 0.72, 0.86, and 0.79, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)