Methionine requirement of pigs between 5 and 20 kilograms body weight.

Four nursery experiments were conducted using a methionine (Met)-deficient feather meal-corn-soybean meal-dried whey basal diet (20% CP; 3,250 kcal of ME/kg, .11% choline, .19% Met, 1.00% cystine) supplemented with lysine, tryptophan, and histidine to determine the Met requirement of 5- to 10- and 10- to 20-kg pigs. Based on a true Met digestibility value of 81.6% estimated by a pig ileal digestibility assay, the Met-deficient basal diet contained .155% of digestible Met. A preliminary experiment (Exp. 1) indicated that pigs fed the Met-deficient basal diet when fortified adequately with Met could produce weight gains similar to those of pigs fed a 20% CP practical corn-soybean meal-dried whey diet. In Exp. 2 and 3, crossbred pigs weighing 5.8 kg initially were fed diets containing graded levels of digestible Met between .195 and .355%. Average daily gain increased quadratically (P less than .05) as the level of Met increased. When the data of Exp. 2 and 3 were examined together, the digestible Met requirement of 5- to 10-kg pigs was estimated to be .255% of the diet. In Exp. 4 and 5, crossbred pigs averaging 10 kg were fed digestible Met concentrations ranging from .155 to .315%. Average daily gain increased quadratically (P less than .05). The digestible Met requirement of 10- to 20-kg pigs was estimated at .255% for maximal weight gain, which was similar to that of 5- to 10-kg pigs. Assuming an 89% digestibility of Met in practical corn-soybean meal diets, the total Met level needed in practice would be .29%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of media to isolate Staphylococcus aureus from teat skin and milking unit liners.

Four procedures were compared for isolation of Staphylococcus aureus from swabbing solutions of teat skin and milking unit liners from commercial dairies. In 2 procedures, 0.1 ml of swabbing solutions were added to either 5 ml Vogel-Johnson or Baird Parker broth media and enriched at 37 degrees C, 4 h. Following enrichment, 0.1 ml culture was transferred to modified Baird-Parker agar and incubated at 37 degrees C, 48 h. In the other 2 procedures, 0.1 ml of swabbing solution was directly placed on either blood or modified Baird-Parker agar plates and incubated at 37 degrees C 48 h. Combining results from all methods, Staphylococcus aureus were isolated from 72 of 913 (7.9%) skin samples, and 34 of 268 liners (12.6%). On average, 43.1% (31/72) of the S. aureus isolates were found by the enrichment in liquid Vogel-Johnson procedure. The average isolation percentage for other methods ranged from 19.4% to 25.0%. Isolation of S. aureus from milking unit liner or teat skin swabbing solutions was approximately twice as likely after enrichment in Vogel-Johnson liquid media as opposed to other methods of isolation. This indicates that enrichment in Vogel-Johnson liquid media improved recovery of S. aureus from swabbing solutions.     

Characteristics of Haemophilus pleuropneumoniae Isolates and Some Epidemiological Findings on Porcine Haemophilus Pleuropneumonia in Saskatchewan

Thirty isolates of Haemophilus pleuropneumoniae from clinical and slautherhouse cases of porcine Haemophilus pleuropneumonia in Saskatchewan as well as six isolates from British Columbia and Ontario were subjected to cultural, biochemical, serological and antibiotic sensitivity tests. All strains were Gram-negative pleomorphic rods or coccobacilli which grew only in the presence of V factor and all produced porphyrin from delta-aminolaevulinic acid. Biochemically, the organism was positive for urease, O-nitrophenyl-β-D-galactopyranosidase and the fermentation of sucrose, mannitol, dextrose, lactose and xylose, but was usually negative for indole. Most strains of H. pleuropneumoniae were sensitive to chloramphenicol, furamazone, carbenicillin and ampicillin, but only about 50% were sensitive to tetracycline. Serotype 5 was more common than serotype 1 or the untyped strains among Saskatchewan isolates. In addition, serotype 3 was identified from British Columbia.

Retrospective epidemiological studies showed that Haemophilus pleuropneumonia occurred and recurred on farms in the Saskatoon and adjoining districts, serviced by the diagnostic laboratories of the Western College of Veterinary Medicine and that the disease was more common among three month old pigs during the fall-winter season.

     

Effect of age and sex on the eviscerated yield,muscle and edible offal of a commercial broiler strain

1. Comparisons of the effects of age (up to 364 d) and sex on the rate of growth, eviscerated yield, blood loss and yield of skin, breast, thigh and drumstick muscles, heart, liver and gizzard have been made on a commercial British broiler strain.

2. Male broilers grew linearly up to 76 d whereas the females grew more slowly after 35 d. At 364 d the difference in live body weight was small.

3. Up to 56 d, males had a slightly higher eviscerated yield. There was no significant difference between the sexes beyond this age.

4. The proportional yield of breast muscle was variable with age, whereas that of thigh and drumstick increased with age in the male, particularly at 175 and 364 d.

5. After 35 d the proportion of skin was larger in females, whereas the gizzard as a proportion of live body weight in both sexes decreased rapidly between 21 and 76 d. Blood loss during killing was always higher in male broilers after 21 d.     

Antibacterial effect of chloramphenicol, thiamphenicol and florfenicol against aquatic animal bacteria

The minimum inhibitory concentration (MIC) was measured to evaluate the antibacterial activities of chloramphenicol (CP), thiamphenicol (TP) and florfenicol (FFC) against the aquatic bacterial isolates from soft-shell turtles, fish and shellfish. Amoxicillin (AMPC), oxytetracycline (OTC) and oxolinic acid (OA) were included to compare with above protein synthesis inhibitors. The results showed that the order of MIC range of the isolates from soft-shell turtles for tested drugs was OA>FFC, CP>TP> AMPC, OTC. The percentage of the resistant strains indicated that OA was the lowest (7.14%) and OTC was the highest (85.07%). The order of antibacterial activity against the isolates from fish was OA>FFC>CP>AMPC>OTC>TP. The percentage of the resistant strains revealed that OA (13.64%) and OTC (80.91%) were the lowest and the highest, respectively. For the isolates from shellfish, the order of antimicrobial activity was OA>CP, FFC>AMPC, OTC, TP. TP showed the greatest percentage of the resistant strains (58.7%), but that of OA was the lowest (4.35%). The most common resistant patterns of the isolates from turtles, fish and shellfish were AMPC-OTC, CP-TP-AMPC-OTC, and FFC-CP-TP-AMPC-OTC, respectively. There were partially-complete resistance of the resistant isolates among CP, TP and FFC. The findings indicated that previous treatment might affect the choice of drug to use for aquatic bacterial diseases.     

Persistence of cellulitis-associated Escherichia coli DNA fingerprints in successive broiler chicken flocks

Avian cellulitis in broiler chickens is primarily caused by Escherichia coli. Previous research found that the E. coli isolates of cellulitis origin were unique to each ranch, suggesting that these E. coli were endemic within the ranch environment. To test the hypothesis that the E. coli associated with cellulitis are endemic in the litter of the broiler house, we designed a study to determine whether E. coli DNA fingerprints associated with cellulitis persist over successive flocks that are grown in the same house. In addition, we assessed the impact of different cleaning and disinfection strategies on this persistence. Two broiler houses were followed on each of five farms over 3-4 flocks. A total of 353 E. coli isolates from cellulitis lesions were analyzed in this study, and 314 of these isolates (89%) were DNA fingerprinted by PFGE. In each ranch, there were several DNA fingerprint patterns that were present over successive flocks, regardless of the cleaning and disinfection strategy utilized. Isolates persisted as long as 191 days, implying that these E. coli are capable of persisting in the broiler house environment for long periods of time. In addition, these E. coli isolates were associated with cellulitis lesions in successive flocks. Thus, the isolates of E. coli that are associated with cellulitis in broiler chickens appear to be endemic in the litter environment of the broiler house.     

Pemphigus foliaceus in association with systemic lupus erythematosus, and subsequent lymphoma in a cocker spaniel

A seven-year-old neutered male cocker spaniel was presented with an 11-month history of generalised bacterial dermatitis. There were skin lesions over the entire body, which were round, slightly raised and encrusted. Skin biopsies were collected and the histological findings were consistent with pemphigus foliaceus. Immunohistochemical staining by the indirect immunoperoxidase method was positive, with desmosomal deposition of immunoglobulin (Ig) G. Haematological analysis revealed a regenerative anaemia and profound thrombocytopenia, while a Coombs' test was positive for polyvalent canine Coombs' reagent and anti-dog IgG. An antinuclear antibody test was positive, with a titre of 10,240. An ophthalmic examination demonstrated low tear production (keratoconjunctivitis sicca). Seven months after initial referral, the dog was re-presented with severe generalised peripheral lymphadenopathy. Radiographic evaluation of the thorax and abdomen revealed enlarged cranial mediastinal and sublumbar lymph nodes. Tru-Cut biopsy from an enlarged lymph node confirmed the diagnosis of lymphoma, which was phenotyped as a B-cell tumour. The diagnosis in this case was systemic lupus erythematosus, with the unusual feature of pemphigus foliaceus, and subsequent development of B-cell lymphoma. The case adds further to knowledge of the protean clinical presentations of canine autoimmune diseases and provides additional evidence for the potential association between autoimmunity and immune-system neoplasia in this species.     

In vitro detection of equine arteritis virus from seminal plasma for identification of carrier stallions

Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU/ml. In vitro detection of EAV by virus isolation supplemented with RT-PCR using seminal plasma was proved to be an effective alternative to the standard test mating as a diagnostic method for carrier stallions.     

Safety of selamectin in dogs

Selamectin is a broad-spectrum avermectin endectocide for treatment and control of canine parasites. The objective of these studies was to evaluate the clinical safety of selamectin for topical use in dogs 6 weeks of age and older, including breeding animals, avermectin-sensitive Collies, and heartworm-positive animals. The margin of safety was evaluated in Beagles, which were 6 weeks old at study initiation. Reproductive, heartworm-positive, and oral safety studies were conducted in mature Beagles. Safety in Collies was evaluated in avermectin-sensitive, adult rough-coated Collies. Studies were designed to measure the safety of selamectin at the recommended dosage range of 6-12mgkg(-1) of body weight. Endpoints included clinical examinations, clinical pathology, gross and microscopic pathology, and reproductive indices. Selected variables in the margin of safety and reproductive safety studies were subjected to statistical analyses. Pups received large doses of selamectin at the beginning of the margin of safety study when they were 6 weeks of age and at their lowest body weight, yet displayed no clinical or pathologic evidence of toxicosis. Similarly, selamectin had no adverse effects on reproduction in adult male and female dogs. There were no adverse effects in avermectin-sensitive Collies or in heartworm-positive dogs. Oral administration of the topical formulation caused no adverse effects. Selamectin is safe for topical use on dogs at the recommended minimum dosage of 6mgkg(-1) (6-12mgkg(-1)) monthly starting at 6 weeks of age, and including dogs of reproducing age, avermectin-sensitive Collies, and heartworm-positive dogs.     

Effect of water restriction on equine behaviour and physiology

Six pregnant mares were used to determine what level of water restriction causes physiological and/or behavioural changes indicative of stress. Nonlegume hay was fed ad libitum. During the first week of restriction, 5 l water/100 kg bwt was available, during the second week 4 l/100 kg bwt and, during the third week, 3 l/100 kg bwt. Ad libitum water intake was 6.9 l/100 kg bwt; at 3 l/100 kg bwt water intake was 42% of this. Daily hay intake fell significantly with increasing water restriction from 12.9 +/- 0.75 kg to 8.3 +/- 0.54 kg; bodyweight fell significantly for a total loss of 48.5 +/- 8.3 kg in 3 weeks. Daily blood samples were analysed; osmolality rose significantly with increasing water restriction from 282 +/- 0.7 mosmols/kg to 293.3 +/- 0.8 mosmols/kg bwt, but plasma protein and PCV did not change significantly. Cortisol concentrations fell from 8.1 ng/ml to 6.4 ng/ml over the 3 week period. Aldosterone fell from 211.3 +/- 74.2 pg/ml to 92.5 +/- 27.5 pg/ml at the end of the first week. The behaviour of 4 of the 6 mares was recorded 24 h/day for the duration of the study. The only significant difference was in time spent eating, which decreased with increasing water restriction from 46 +/- 3% to 30 +/- 3%. It is concluded that water restriction to 4 l/100 kg bwt dehydrates pregnant mares and may diminish their welfare, but is not life- or pregnancy-threatening.