Feedlot performance of Brahman x Angus versus Angus steers during cold weather

Ten Angus and 10 Brahman x Angus F1 steers were used in a 184-d trial to compare feedlot performance during cold weather (-9 to 26 degrees C). Both groups of steers were exposed to the same environment for the same amount of time. All steers were fed for the same number of days regardless of frame score to avoid frame score x environment interactions. Brahman x Angus steers were 30.7 kg heavier (P less than .05) than Angus steers at the start of the trial. Differences in age (Brahman x Angus 40 d younger) for the two breed groups did not affect final live weight or carcass weight. Brahman x Angus steers consumed .2% less feed (P less than .05) as a percentage of BW than Angus steers; however, there was no difference in overall feed efficiency. Angus steers had a higher yield grade, more fat at the 12th rib (P less than .05), and graded 90% Choice; only 10% of the Brahman x Angus were graded Choice. Brahman x Angus steers were taller at the hip (P less than .05) and longer from first rib to aitch bone (P less than .05) and from thoracic vertebrae (T12/T13) to point of hock (P less than .05). Hide thickness determined at the neck, belly, and rump was found to be similar (7.7 mm) between the two groups. Sample hair weight and diameter did not differ between groups. Fiber, fat, protein, and DM digestibility coefficients were similar between groups but Brahman x Angus feces had a higher DM content.(ABSTRACT TRUNCATED AT 250 WORDS)     

Resistance of Pasteurella multocida A:3,4 to phagocytosis by turkey macrophages and heterophils

A virulent field isolate and 2 vaccine strains of Pasteurella multocida A:3,4 were compared for resistance to phagocytosis by turkey macrophages and heterophils, using in vitro assays. The least virulent vaccine strain (M-9) was phagocytosed to a greater degree than was the field isolate or the other vaccine strain (Clemson University). All 3 bacteria differed significantly from each other in the amount of capsular material present as measured by polycationic ferritin labeling and electron microscopy. Removal of the capsule with hyaluronidase resulted in a significant increase in phagocytosis of the field isolate.     

Relationship between virulence and adherence of various enterotoxigenic Escherichia coli strains to isolated intestinal epithelial cells from Chinese Meishan and European large white pigs

In vitro adherence to intestinal epithelial cells by enterotoxigenic Escherichia coli strains bearing K88, K99, F41, or 987P adhesins and of their variants not bearing adhesins (K88-, K99-, or F41-) was investigated in European Large White and Chinese Meishan pigs. Possible relationship between adherence and virulence was also examined. The K88-positive (K88+) strain strongly adhered to intestinal epithelial cells from 26 of 28 Large White pigs. This strain had previously been found to be highly virulent for Large White pigs. The only surviving pig was of nonadherent phenotype, and cells from 4 dehydrated moribund pigs had strong adherence. By contrast, the same K88+ strain found previously to have little pathogenicity for Meishan pigs adhered with variable intensity to cells from 17 of 23 Meishan pigs; correlation was not evident between adherence and virulence. The K99+ F41+ strain of porcine origin and the F41+ strain generally adhered strongly to cells from 24 and 23 Meishan pigs, respectively, and to cells from 25 of 26 Large White pigs. Correlation was not found between adherence and virulence for the 2 strains. A K99+ F41+ strain of bovine origin adhered to cells from 20 of 22 Meishan and 22 of 23 Large White pigs, and a K99- F41+ variant adhered to cells from 19 of 23 Meishan and 23 of 24 Large White pigs. The adhesin-negative variants never adhered to intestinal epithelial cells. Strain 987 known not to readily produce 987P adhesin after in vitro growth never adhered to cells during the test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of nutrition and body condition on pituitary, ovarian, and thyroid function of nonlactating beef cows

Nonpregnant Hereford cows (n = 70) were used to determine the effect of nutrient intake and body condition on reproductive and thyroid function. Body condition scores (BCS; 1 = emaciated; 9 = obese) of cows averaged 5.0 +/- .2 on July 1, and cows were fed for 4 mo either to lose weight and BCS (thin; n = 22), to maintain weight and BCS (moderate; n = 24), or to gain weight and BCS (fat; n = 24). After November 1, cows received a complete ration to maintain weight and BCS. Cows were slaughtered in December (six thin, eight moderate, and eight fat cows) or the subsequent March (16 cows per group). Before slaughter, cows were given two injections of prostaglandin F2 alpha (PGF) 11 d apart. Six days after the second PGF injection, cows were simultaneously treated with 100 micrograms of gonadotropin releasing hormone (GnRH; i.m.) and 100 micrograms of thyrotropin releasing hormone (TRH; i.v.) and serum samples were obtained. The BCS of cows at slaughter (8 d after PGF) averaged 3.4, 5.3, and 7.1 (P less than .01) and carcass energy content averaged 243, 432, and 714 Mcal (P less than .01) for thin, moderate, and fat cows, respectively. Wet ovarian (P less than .001) and corpora lutea (P less than .01) weights were heavier for fat cows. Content of LH in the pituitary gland and concentrations of thyroxine (T4) in serum after GnRH/TRH were not influenced by nutrient intake or BCS. However, thin cows had greater concentrations (P less than .05) of LH in serum after GnRH/TRH than did moderate or fat cows. We conclude that nutrient intake and body energy reserves of beef cows influenced ovarian function and LH in serum after treatment with GnRH.     

Susceptibility of Chinese Meishan and European large white pigs to enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, K99, or F41

Conventionally raised Chinese Meishan and European Large White pigs were intragastrically challenge exposed with 2.1 x 10(10) enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, F41, or F41 plus K99. In response to challenge exposure with the K88-positive (K88+) organisms, 96% of Large White pigs died within 48 hours, whereas none of the Meishan pigs died. Both breeds of pigs had similar susceptibility to strains bearing 987P or F41. Lastly, Meishan pigs were found to be more susceptible than Large White pigs to a strain expressing K99 and F41. In pigs with diarrhea, challenge-exposure strains intensively colonized the jejunum (10(8) to 10(10) bacteria/g of tissue) and, to less extent, the duodenum (except K88+ strain, which comprised 10(8)/g). In most cases, jejunal concentrations of the challenge-exposure strains were substantially lower in pigs that did not have diarrhea. Half the resistant Meishan pigs eliminated the K88+ strain from the intestines. Colostral antibody titer that agglutinated challenge-exposure strains did not differ between Meishan and Large White gilts. Results indicate that resistance of pigs to the K88+ strain did not extend to enterotoxigenic strains bearing other well-known factors. They indicate, in addition, that genetic resistance to K88+ strains described in pigs in Europe may exist in pigs in China.     

Aortic stenosis: clinical findings in six cats

Congenital aortic stenosis was diagnosed in six cats. Clinical findings included dyspnoea, systolic murmurs with maximal intensity at the left apex or right sternal border, and cardiomegaly with congestive heart failure. Some clinical features of feline aortic stenosis were similar to those observed in cats with hypertrophic cardiomyopathy. Definitive diagnosis was obtained by angiographic imaging of a discrete, consistent subvalvular obstruction, Doppler-echocardio-graphy, or by necropsy. Although, two of the cats were diagnosed at ages older than usually reported, the overall prognosis for cats with aortic stenosis was poor. Four of the six cats died or were euthanased within one year of the onset of clinical signs.     

Rapid infection in market-weight swine following exposure to a Salmonella typhimurium-contaminated environment

OBJECTIVE: To evaluate the possibility of swine becoming infected with Salmonella Typhimurium when housed for 2 to 6 hours in an environment contaminated with Salmonella, similar to a lairage situation prior to slaughter. ANIMALS: 40 crossbred market pigs with an approximate body weight of 92 kg. PROCEDURE: Five trials were conducted (8 pigs/trial) in simulated lairage conditions. Superficial inguinal, ileocecal, and mandibular lymph nodes, cecal contents, distal portion of the ileum, and fecal samples were obtained from each pig after 2 (n = 10), 3 (10), and 6 (5) hours of exposure to an environment contaminated with feces defecated by 10 pigs intranasally inoculated with nalidixic acid-resistant Salmonella Typhimurium (chi4232). In addition, 5 control pigs that were not exposed were also evaluated in the same manner. RESULTS: Feces deposited on the floor by intranasally inoculated swine were mixed with water to form slurry with a resulting load of approximately 10(3) colony-forming units of Salmonella Typhimurium/g of material. Eight of 10, 6 of 10, and 6 of 6 pigs exposed to the slurry for 2, 3, or 6 hours, respectively, had positive results for at least 1 sample when tested for the specific strain of Salmonella Typhimurium. CONCLUSIONS AND CLINICAL RELEVANCE: Pigs can become infected during routine resting or holding periods during marketing when exposed to relatively low amounts of Salmonella organisms in the preslaughter environment. Intervention at this step of the production process may have a major impact on the safety of pork products.     

Animal-derived feeds as possible vectors for bovine spongiform encephalopathy (BSE) in Germany. 1. Comparative risk assessment for a single animal food of animal origin

The occurrence of BSE cases in Germany after the ban of meat and bone meal for ruminant feed in 1994 requires a detailed investigation of animal derived feedstuffs regarding their specific risks as vectors for the disease. Accepting the theory that BSE is a prion transmitted disease, the theoretical infectious potential was calculated for animal derived feedstuffs. This calculation was based on the assumption, that risk material (brain, spinal cord) of one clinically diseased cattle was rendered in the process as established in Germany (133 degrees C, 3 bar, 20 min) or, alternatively, that one diseased animal was slaughtered resulting in normal processing of the by-products for human food production. From this risk assessment it became obvious that meat and bone meal was one, but probably not the most important source for the spreading of BSE. Taking into account the high sensitivity of calves it can be speculated that certain products, e.g. from bone processing (bone meal) and fat melting (mixed animal fats), commonly used for the formulation of milk replacers, might have been more important as pathways. As it can't be excluded retrospectively that infected meat and bone meal was imported from the UK, this non-calculable influence may have been related to the significance of the other products. The calculation model underlines that efficient removal of specified risk material (brain, spinal cord) and adequate processing (133 degrees C, 3 bar, 20 min) or alternatively other equivalent treatments of fats are prerequisites for minimising the risk of feed borne transmission of BSE by animal derived feedstuffs. The epidemiological consequences are part of a subsequent paper.     

Importation of parasites by tourism and animal trading

International transport of animals is associated with an enhanced risk of import of a number of parasite species that are not endemic in Germany. Pets accompany tourists on journeys all over the world, but in particular to southern Europe, and dogs are increasingly imported from (sub-)tropical countries for reasons of animal welfare. Veterinary practitioners are thus confronted with parasites that are unusual in their patients. The specific transmission routes determine whether an imported parasite is able to become endemic. Although parasites eradicated in Germany such as Trypanosoma equiperdum and Tritrichomonas foetus may be principally imported they are unlikely to re-establish due to the current epidemiological conditions. Imported animals that harbour parasites which may occur naturally but are currently rare in Germany are a potential source of increased infection risk. Certain areas in Germany have probably become endemic for Babesia canis and the respective vector tick Dermacentor reticulatus has been found. Whether other vector borne parasitic diseases such as leishmaniosis or heartworm disease have the potential to spread into Germany is still a matter of debate.