Growth performance and carcass composition of lambs infused for 28 days with a growth hormone-releasing factor analogue.

A human growth hormone-releasing factor analogue, [DesNH2Tyr1,D-Ala2,Ala15]hGRF(1-29)NH2 (GRF-A), was infused s.c. into lambs for 28 d to determine its effects on growth performance and carcass composition. Twenty crossbred wethers weighing 47.0 +/- .5 kg were implanted with 7-d osmotic minipumps at weekly intervals. Minipumps contained either vehicle (dimethyl sulfoxide:H2O, 1:1) or GRF-A, released at a rate of 208 pmol (or .7 micrograms).h-1.kg-1. During the infusion period, plasma GH levels were increased (P less than .01) in GRF-A-treated wethers compared with control wethers (15.0 vs 9.3 ng/ml) and were higher on days that closely followed minipump implantation. Plasma IGF-I and hepatic IGF-I RNA concentrations were similar in lambs of both groups. Analogue treatment improved feed conversion (4.9 vs 5.8 kg dry matter/kg gain, P less than .05), increased average daily gain (.35 vs .30 kg, P = .05) and had no effect on feed intake, wool growth and body, carcass, selected organ and pituitary weights. Carcasses from GRF-A-infused lambs had less adjusted fat depth, a lower percentage of fat and a higher percentage of protein (P less than .05) than carcasses from control lambs. Magnitude of most effects of GRF-A on carcass measurements were correlated with the mean GH level that a lamb had during the infusion period. In conclusion, s.c. infusion of GRF-A improved feed utilization and altered carcass composition of feeder lambs in a relatively short period of time (28 d).     

Interrelationships between energy intake and endogenous porcine growth hormone administration on the performance, body composition and protein and energy metabolism of growing pigs weighing 25 to 55 kilograms live weight

Thirty-six barrows were used in a 2 X 3 factorial experiment to investigate the effects of porcine growth hormone (pGH) administration (USDA-pGH-B1; 0 and 100 micrograms.kg body weight-1.d-1) and three levels of feeding of a single diet (EI; ad libitum, 1.64 and 1.38 kg/d) on the performance, body composition and rates of protein and fat deposition of pigs growing over the live weight phase 25 to 55 kg. Raising EI resulted in linear increases in growth rate and in protein and fat accretion but had no effect on the feed to gain ratio (F/G). Carcass fat content and carcass fat measurements also increased with EI, whereas carcass protein and water decreased (P less than .01). Growth hormone administration resulted in improvements in growth rate (16 to 26%), F/G (23%), protein deposition (34 to 50%) and increases in carcass protein and water at each level of feeding, but reduced ad libitum feed intake (P less than .01), carcass fat content (P less than .01) and carcass fat measurements (P less than .01). Estimated maintenance energy expenditure was increased by pGH administration (2.02 vs 1.72 Mcal digestible energy/d). Results indicate that the effects of pGH on growth performance and energy and protein metabolism were largely independent of, and additive to, the effects of energy intake.     

Interrelationships between exogenous porcine somatotropin (PST) administration and dietary protein and energy intake on protein deposition capacity and energy metabolism of pigs

Exogenous porcine somatotropin (PST) administration stimulates protein deposition and inhibits lipogenesis, resulting in dose-related improvements in growth performance and reduction of carcass fat content. However, the associated impacts of this technology on dietary nutrient requirements and energy partitioning between maintenance, protein, and fat remain unclear. Studies with pigs between 25 and 60 kg body weight indicate that, because of unknown improvements in amino acid utilization and(or) in the energy available for protein synthesis, only marginal increases in dietary protein percentage are required to support 20 to 25% improvements in protein deposition induced by PST administration. In contrast, an increased dietary protein concentration is required to support maximal protein deposition in pigs 60 to 100 kg. Exogenous PST administration increased the maintenance energy requirement and altered the relationship between energy intake and protein deposition, although the magnitude of these changes and the consequent effects on expression of dietary protein (amino acid) requirements was influenced by gender. Albeit limited, information suggests that PST alters nutrient demand at the tissue level. Information of this type will form the basis for rational decisions concerning the method for expression of dietary nutrient requirements (% vs g/d) for PST-treated pigs. Further quantitative information is required on the effects of PST dosage on the relationship of protein deposition to energy intake and on any underlying changes in amino acid utilization and metabolism.     

Tolerance of young turkey poults to various combinations of dietary furazolidone and salt.

Three feeding trials were conducted to study the tolerance of young turkey poults to furazolidone and to various combinations of salt and furazolidone in the diet. Poults of mixed sexes tolerated up to 0.03% dietary furazolidone from hatch to six weeks of age without harmful effects as judged from the data on mortality rate, feed intake, body weight and plasma composition. High mortality with cardiac dilation and ascites occurred in poults fed the same basal diet containing 0.05 or 0.07% furazolidone. Mortality was positively related to levels of dietary furazolidone, and occurred mainly between two and four weeks of age. The cumulative feed intake and body weight of these poults were significantly lower than those of the control poults at six weeks of age. There was indication of decreased renal function in poults on high furazolidone intake and the mechanism of furazolidone-induced cardiac dilation is discussed. Mortality rate, incidence of cardiac dilation with ascites and heart, liver and body weights and feed efficiency were similar in poults fed diets containing 0.022% furazolidone and varying levels of salts (0.5, 1.0 or 1.5%) compared with the control fed the same basal diet containing 0.5% salt from hatch to eight weeks of age. It is concluded that a starter diet containing 0.022% furazolidone and up to 1.5% salt does not affect the performance of poults from hatch to eight weeks of age.     

The development of a fluidic controlled ventilator for the horse

SUMMARY The system consists of a modified Campbell ventilator driving a large ‘bellows in a bottle’ which connects with a large animal circle system incorporating a carbon dioxide absorber. Tidal volumes up to 14 litres can be achieved while fresh gas flow into the circle can be kept as low as 6 litres per minute.     

In vitro screening of novel treatments for Aphanomyces invadans

Forty‐nine compounds were tested in vitro for fungicidal activity against hyphae of the fish‐pathogenic Oomycete fungus, Aphanomyces invadans. These comprised: (a) chemicals with previous reported activity against Oomycete fungi; (b) chemicals in use in Asia to treat ulcerative disease outbreaks; (c) commercial biocides and fungicides; (d) natural products with potential antimicrobial activity; and (e) surfactants tested separately and in combination with some of the above treatments. No compounds tested proved as effective as malachite green, but some low‐toxicity natural compounds and particular surfactants showed potential for further studies. Some compounds that are currently in use in Asian aquaculture were shown to have no effect on A. invadans hyphae at recommended treatment rates. A range of compounds that demonstrated activity against the mycelium were selected for further testing in a zoospore motility assay. Lower treatment concentrations were required to inhibit zoospore motility than were required to inhibit hyphal growth. Zoospore activity ceased within 1 h of exposure to 2.5 parts per million (p.p.m.) coconut diethanol‐ amide; 1.25 p.p.m. propolis + 0.5 p.p.m. 13/6.5; 5 p.p.m. neem (Azadirachta siamensis) seed extract + 0.01 p.p.m. OP10; 20 p.p.m. tea tree (Melaleuca alternifloria) oil; and 25 p.p.m. D‐limonene + 0.05 p.p.m. E‐Z‐Mulse^TM. The treated spores were shown to be non‐viable in culture medium. Selected compounds were further tested for ability to inhibit zoospore production by A. invadans mycelium over a 72‐h period. In toxicity trials, silver barb, Barbodes gonionotus (Bleeker), exposed to 2.5 p.p.m. coconut diethanolamide; 2.5 p.p.m. OP10; 0.5 p.p.m. E‐Z‐Mulse^TM; 20 p.p.m. neem seed extract + 0.5 p.p.m. OP10; and 5 p.p.m. D‐limonene + 0.5 p.p.m. E‐Z‐Mulse^TM suffered no mortalities and no obvious behavioural changes. Similarly, rainbow trout, Oncorhynchus mykiss (Walbaum), exposed to 25 p.p.m. propolis + 1 p.p.m. OP10; 10 p.p.m. neem seed extract + 0.01 p.p.m. 13/6.5; and 10 p.p.m. D‐limonene + 0.01 p.p.m. OP10 suffered no mortalities and no obvious behavioural changes.     

An atypical lymphoma of T-cell lineage in the thorax of an aged cow.

An aged beef cow was presented for signs of thoracic disease. A complete clinical and diagnostic workup suggested neoplasia. Postmortem examination revealed a lymphoma of T-cell lineage confined solely to the thoracic cavity, predominantly in lung tissue. The diagnosis was based on light and electron microscopy, immunohistochemistry, and negative bovine leukemia virus and bovine immunodeficiency virus results.     

GRANULOMATOUS AND NEOPLASTIC DISEASES OF THE SKIN OF HORSES

Lesions encountered in a clinicopathological study of cutaneous lesions resembling 'swamp cancer' from horses in North Queensland included 37 cases of subcutaneous phycomycosis, 5 of which were also infected with Habronema sp larvae. In addition 9 cases of primary cutaneous habronemiasis, 58 sarcoids, 12 fibromas, 8 fibrosarcomas, 10 squamous cell carcinomas, 4 haemangiomas, 3 melanomas, 1 papilloma, 1 palpebral adenocarcinoma and 7 cases of simple granulation were diagnosed. Subcutaneous phycomycosis resulted in the most extensive lesions. These were rapidly growing and provided the poorest prognosis of all conditions studied. The incidence of phycomycosis in north Queensland was high in comparison to more temperate areas and appeared to be related to the wetter seasons. Young horses were more commonly affected. A fungus isolated from 3 phycomycotic lesions was tentatively identified as Hyphomyces destruens as no sporulation was observed.