Adrenocortical Response in Cows after Intramuscular Injection of Long‐Acting Adrenocorticotropic Hormone (Tetracosactide Acetate Zinc Suspension)

The objectives of this study were first to show adrenocortical response to a long‐acting adrenocorticotropic hormone preparation (tetracosactide acetate zinc suspension) (ACTH‐Z) and its effect on adrenocortical function in beef cows ( Experiment 1 ) and second to apply the ACTH‐Z challenge in dairy cows based on cortisol concentrations in milk collected at routine milking ( Experiment 2 ). In Experiment 1 , four beef cows in luteal phase were challenged with ACTH‐Z, and plasma cortisol concentrations were determined for 48 h after the injection at 30‐min to 2‐h intervals. A rapid ACTH test was conducted 3 days before and 2 h after the completion of ACTH‐Z injection for 48 h to investigate the effect on adrenocortical function. Plasma cortisol concentrations increased significantly 30 min after ACTH‐Z injection (p < 0.001), and the high cortisol levels were maintained for approximately 10 h after the injection. In Experiment 2 , eight dairy cows were subjected to ACTH‐Z challenge 1–2 weeks and 4–5 weeks post‐partum. Blood and milk samples were taken at morning and afternoon milking. All the cows showed a significant increase in cortisol concentrations in plasma as well as in skim milk 8 h after ACTH‐Z injection 1–2 weeks and 4–5 weeks post‐partum (p < 0.001). There was a significant correlation between plasma and skim milk cortisol concentrations 8 h after ACTH‐Z challenge (r = 0.74, p < 0.001). The results obtained in this study suggest that elevated levels of plasma cortisol are maintained for approximately 10 h after ACTH‐Z treatment without adverse effect on adrenocortical function and a long‐acting ACTH‐Z challenge based on cortisol concentrations in milk, which were collected at the morning and the afternoon milking, can be a useful tool to monitor adrenocortical function in cows.     

Involvement of PAPP‐A and IGFR1 in Cystic Ovarian Disease in Cattle

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been shown that intra‐ovarian factors, such as members of the insulin‐like growth factor (IGF) system, may contribute to follicular persistence. The bioavailability of IGF to initiate its response by binding to specific receptors (IGFRs) depends on interactions with related compounds, such as pregnancy‐associated plasma protein A (PAPP‐A). The aim of this study was to determine IGFR1 and PAPP‐A expression both in follicles at different stages of development and in cysts, to evaluate the roles in the etiopathogenesis of COD in cattle. The mRNA expression of PAPP‐A was higher in granulosa cells of large tertiary follicles than in cysts, whereas the protein PAPP‐A present in the follicular fluid from these follicles showed no differences. Although no PAPP‐A mRNA expression was detected in smaller tertiary follicles, in their follicular fluid, this protease was detected in lesser concentration than in cysts. The mRNA expression of IGFR1 was lower in granulosa cells from cystic follicles than in those from tertiary ones. However, the protein expression of this receptor presented the highest levels in cystic structures, probably to increase the possibility of IGF response. The data obtained would indicate that animals with COD have an altered regulation of the IGF system in the ovary, which could be involved in the pathogenesis of this disease in cattle.     

Chemical composition of walnuts (Juglans regia L.) grown in New Zealand

Walnuts (Juglans regia L.) werecollected during the 1997 harvest from 12 differentcultivars of trees grown in a replicated trial in anexperimental orchard at Lincoln University. Two UScommercial cultivars (Tehama and Vina), three Europeancommercial cultivars (Esterhazy, G139, G120) and eightNew Zealand selections (Rex, Dublin's Glory, Meyric,Stanley, 150, 151, 153) were evaluated. The total oilcontent ranged from 62.6 to 70.3% while the crudeprotein ranged from 13.6 to 18.1%. Dietary fiberranged from 4.2 to 5.2% while the starch content madeup no more than 2.8% of the remaining portion of thekernel. The amino acid content of the walnuts wassimilar between cultivars and the patterns ofessential amino acids were characteristic of a highquality protein.     

Effects of nitrate‐, ammonium‐, and organic‐nitrogen‐based fertilizers on growth and yield of tomatoes

Mineral and organic fertilizers contain different forms and amounts of nitrogen (N), which can affect yield and product quality. The aim of this study was to determine appropriate amounts of N applied as nitrate (NO ), ammonium (NH ), and organic N (a mixture based on chicken manure) for optimal growth and quality of tomatoes. A pot experiment with sand as substrate was established in a greenhouse with six‐week‐old tomato plants (Lycopersicon esculentum Mill. cv. “Armada”). Nitrogen was applied in nutrient solutions at different NO : NH ratios combined with different chloride levels (NO ‐dominated, NO = NH at low Cl^–, NO = NH at high Cl^–, and NH ‐dominated, respectively) or as organic N at four N‐application rates (250, 500, 750, 1000 mg N plant^–1 week^–1). No significant differences in shoot biomass and yields of red tomatoes were observed between NO ‐ or NH ‐fed plants. Nitrogen rates above 750 mg N plant^–1 week^–1 did not significantly increase marketable fruit yield, but enhanced shoot‐biomass production. The NH ‐N‐dominated treatments (which also had high Cl^– concentrations) showed increasing incidence of blossom‐end‐rot (BER)‐infected fruits. In the organic‐N treatments, shoot‐biomass production and yields were lower than in the inorganic‐N treatments, but fruit quality was good with few BER‐infected fruits. The results show that with a total N supply below 750 mg N plant^–1 week^–1, NH can be used as equivalent N source to NO , resulting in equivalent yields of marketable fruit under the conditions in this experiment.     

Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985–2004)

AIMS: To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions.

METHODS: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome.

RESULTS: All horses except one were less than 12 months old. Standardbreds were over-represented in the population studied. Sixteen horses (72%) had been administered anthelmintics, including pyrantel (n=8), ivermectin (n=7), and trichlorphon (n=1), within 24 h prior to the onset of colic. Of the 25 cases reviewed, 16 had simple obstructive ascarid impactions (SOAIs), and nine had complicated obstructive ascarid impaction (COAI) including volvulus (n=6) or intussusception (n=3), both concurrent with ascarid impaction of the small intestine. Short-term survival (discharge from hospital) occurred in 79% of horses treated for SOAI, and was 64% for all horses. Long-term survival (>1 year) occurred in 33% of horses with SOAI, and the overall long-term survival was 27% for all horses. Formation of adhesions was the most frequent finding associated with death for horses that did not survive long-term.

CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of anthelmintic treatment within 24 h of the onset of colic in this study population (72%) was higher than that previously reported. Resistance of P. equorum to ivermectin recently reported in Ontario may be associated with increased ascarid burdens, predisposing horses to ascarid impaction. The long-term survival of these horses was better than that reported previously.     

Effects of hyperimmune equine plasma on clinical and cellular responses in a low-dose endotoxaemia model in horses

Endotoxaemia is a major cause of equine morbidity, and plasma from horses immunised against Escherichia coli is used in its treatment. The aim of this study was to determine the effects of hyperimmune plasma on the clinical and leukocyte responses, including production and activity of TNFα, in an in vivo endotoxin challenge model. Pre-treatment with hyperimmune equine plasma had no significant effect on peak total plasma TNFα concentration (occurring 90min after the administration of 30ng/kg LPS). However, the bioavailable (unbound) TNFα measured by bioassay was significantly reduced in plasma-treated horses (1044.44±193.93pg/ml at 90min) compared to saline treated controls (1373.92±107.63pg/ml; P=0.05). Therefore, although pre-treatment with hyperimmune equine plasma did not significantly modify the clinical signs of endotoxaemia in this model, there was some evidence of reduced TNF bioactivity, which may be due to factors in the plasma which bind and reduce the activity of this cytokine.     

Stream types in Idaho: An approach to classification of streams in natural areas

Five types among small streams are described: ephemeral streams, spring streams, and three types among permanent streams. Key features used to designate stream type are order, gradient, pattern of flow, and substrate which are readily identifiable, nonvariable characteristics. Type designation is supported on an ecological basis by analysis of extensive collections of aquatic plants and invertebrates.