Phosphatase activity in avian mycoplasmas.

Fifty-four strains of avian mycoplasma representing 11 species or serotypes were examined for their phosphatase activity using two different methods. Both methods gave similar results. All of four strains of Mycoplasma anatis and six of M meleagridis and the type strain of serotype L were phosphatase positive. The other species gave variable reactions between strains and on different occasions of testing.     

Effect of long-term tetracycline exposure (drinking water additive) on antibiotic-resistance of aerobic gram-negative intestinal flora of rats.

A study was undertaken to determine the effect of 2 years of intermittent administration of tetracycline in drinking water on antibiotic resistance in the aerobic gram-negative enterobacteria of rats in a closed colony. The bacterial isolates examined were resistant to tetracycline and streptomycin. Minimal inhibitory concentrations of tetracycline and streptomycin for intestinal organisms were similar in all of the animals, regardless of whether the animals were sampled while they were given drinking water with added tetracycline or at intervals of 3, 8, and 9 months after the antibiotic was no longer added to the drinking water. Biochemical examination of the isolates from each principal showed that Escherichia coli was the predominant enteric organism. In conjugation experiments, all E coli and Klebsiella pneumoniae isolated transferred tetracycline and streptomycin resistance to an E coli K-12 recipient. Four different strains of rats that had not been treated with tetracycline (controls) were examined for tetracycline resistance. Tetracycline-resistant Proteus mirabilis was isolated from the intestines of these animals. Plasmid-mediated resistance could not be demonstrated. The E coli and P vulgaris isolates from these control animals were susceptible to tetracycline.     

Primary hyperparathyroidism in a dog.

A 6-year-old male Standard Poodle had hypercalcemia, hypophosphatemia, and a urinary concentrating defect. A parathyroid adenoma involving the left caudal parathyroid gland was surgically removed. Transient hypocalcemia followed, which resolved without treatment. A renal biopsy did not demonstrate renal parenchymal mineral deposition. Urinary concentrating ability returned after surgery.     

Fertility in buffaloes after oestrus synchronisation with cloprostenol and fixed time insemination.

Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.     

Polioencephalomalacia associated with canine distemper virus infection

Eight dogs with severe neurologic signs, including seizures, had polioencephalomalacia of the pyriform cortex, Ammon's horn and deep structures in the temporal lobe. The polioencephalomalacia was considered to be a consequence of canine distemper virus infection based on clinical signs, typical inclusions, the demonstration of viral antigens in the lesions and of characteristic paramyxovirus nucleocapsids by electron microscopy. Little evidence for neuronal destruction by direct viral activity was found. Selective nerve cell necrosis was attributed to ischemia (vascular lesions and seizure induced consumptive anoxia) and immune mechanisms. The selective involvement of the rhinencephalic structures was thought to be related to the mode of entry and spread of the virus.     

Fascicular nerve biopsy in the dog

A nerve fascicular biopsy technique that preserves the functional integrity of the parent nerve is reported in the dog. Fascicular biopsies from ulnar and peroneal nerves did not produce clinical sensory or motor deficits. Electrodiagnostic testing for the modalities of latency, duration, amplitude, and conduction velocities were not markedly altered after fascicular biopsies. Morphometric analysis of muscle fiber types, delineated by histochemic techniques, revealed no statistical (P greater than 0.05) difference between muscles from biopsied or control limbs. Fascicular biopsies resulted in small neuromas in all dogs.     

Reducing the proportion of animal protein in feed for rainbow trout (Salmo gairdneri). 2. Supplementation of methionine and lysine

Continuing previous investigations, two test feedstuffs whose fishmeal content had been reduced to 5% and which were supplemented with 4.5 g methionine and 5.0 g lysine per kg resp. 6 g methionine and 6 g lysine per kg were proofed in comparison with a fattening feed for trout as customary in trade and with a fish meal content of 35%. The content of animal protein in the control feed was at least 75% (crude protein content 41%), in test feed I at most 35% (crude protein content 35.4%), in test feed II at most 17% (crude protein content 33.9%). All feedstuffs had the same energy content. The tests were made with rainbow trout (Salmo gairdneri) of 80...100 g at the beginning and at water temperatures of 11...12 degrees C. They were conducted over a period of 112 days. After giving the same amount of feed, growth of and feed expenditure for the fish feed with the test feedstuffs were less suitable than of those fish which had received the control feed. Concerning the protein efficiency ratio, the productive protein value and the energetic expenditure too, the best results were achieved with the control feed.     

Factors affecting dystocia and offspring vigour in different sheep genotypes

Birth difficulty and poor lamb vigour are significant causes of perinatal lamb mortality. In this study we investigated whether sheep breeds differing in appearance, muscularity and selection history also had differences in dystocia and lamb vigour, and considered some of the factors that may contribute to the variation in these traits. Data were collected at birth from a total of 3252 lambs of two terminal sire breeds selected for lean growth (Suffolk [S], n = 500 and Texel [T], n = 1207), from a Hill breed (Scottish Blackface [B], n = 610), which has been mainly selected for hardiness, and a crossbred (Mule × T [M], n = 935) representing a maternal line. For each lamb the degree of assistance at delivery, lamb presentation, amount of assistance to achieve successful sucking, sex, litter size and birth weight were recorded. T lambs required the most, and B and M lambs the least assistance at birth, S lambs were intermediate (% lambs assisted: T = 55.7, S = 30.7, B = 22.7, M = 24.9, P < 0.001). T and S lambs were equally likely to be malpresented at birth (29% of births) and more likely to be malpresented than B or M lambs (20%; P < 0.001). In T and S breeds lambs requiring veterinary assistance at delivery were mainly heavy and singleton lambs, whereas in B and M breeds these were exclusively low birth weight lambs in multiple litters. Although heavier lambs needed greater birth assistance, T lambs were lighter than S and M lambs, but heavier than B lambs (birth weight (kg): S = 4.66, M = 4.56, T = 4.32, B = 3.67, P < 0.001). S lambs were more likely to require assistance with sucking than other breeds, and T lambs also required more assistance than B or M lambs (% lambs assisted to suck: S = 56.0, T = 31.6, M = 19.8, B = 18.4, P < 0.001). Heavier lambs were more likely to suck unaided than lighter lambs (P < 0.001). The data suggest that the two terminal sire breeds, selected narrowly for greater productivity (muscle growth and conformation), are more likely to experience birth difficulty and poorer lamb vigour than the breed selected for hardiness, or the cross breed. Whether these effects arise as a consequence of genetic selection (e.g. for specific lamb conformation), or as a result of management practices to achieve selection goals (e.g. increased intervention at lambing) is unknown. Specific actions to improve birth difficulty and lamb vigour, such as including these traits in the selection index, would be beneficial in improving the welfare of ewes and lambs of the terminal sire breeds.