Stress and immunological response of heifers divergently ranked for residual feed intake following an adrenocorticotropic hormone challenge

Background: When an animal is exposed to a stressor, metabolic rate, energy consumption and utilisation increase primarily through activation of the hypothalamic-pituitary-adrenal(HPA) axis. Changes to partitioning of energy by an animal are likely to influence the efficiency with which it is utilised. Therefore, this study aimed to determine the physiological stress response to an exogenous adrenocorticotropic hormone(ACTH) challenge in beef heifers divergently ranked on phenotypic residual feed intake(RFI).Results: Data were collected on 34 Simmental weaning beef heifers the progeny of a well characterized and divergently bred RFI suckler beef herd. Residual feed intake was determined on each animal during the postweaning stage over a 91-day feed intake measurement period during which they were individually offered adlibitum grass silage and 2 kg of concentrate per head once daily. The 12 highest [0.34 kg DM/d] and 12 lowest[-0.48 kg DM/d] ranking animals on RFI were selected for use in this study. For the physiological stress challenge heifers(mean age 605 ± 13 d; mean BW 518 ± 31.4 kg) were fitted aseptically with indwelling jugular catheters to facilitate intensive blood collection. The response of the adrenal cortex to a standardised dose of ACTH(1.98 IU/kg metabolic BW~(0.75)) was examined. Serial blood samples were analysed for plasma cortisol, ACTH and haematology variables. Heifers differing in RFI did not differ(P = 0.59) in ACTH concentrations. Concentration of ACTH peaked(P 0.001) in both RFI groups at 20 min post-ACTH administration, following which concentration declined to baseline levels by 150 min. Similarly, cortisol systemic profile peaked at 60 min and concentrations remained continuously elevated for 150 min. A RFI × time interaction was detected for cortisol concentrations(P = 0.06) with high RFI heifers had a greater cortisol response than Low RFI from 40 min to 150 min relative to ACTH administration. Cortisol response was positively associated with RFI status(r = 0.32; P 0.01). No effect of RFI was evident for neutrophil, lymphocytes, monocyte, eosinophils and basophil count. Plasma red blood cell number(6.07 vs. 6.23; P = 0.02) and hematocrit percentage(23.2 vs. 24.5; P = 0.02) were greater for low than high RFI animals.Conclusions: Evidence is provided that feed efficiency is associated with HPA axis function and susceptibility to stress, and responsiveness of the HPA axis is likely to contribute to appreciable variation in the efficiency feed utilisation of cattle.     

Pharmacokinetics of liposomal encapsulated buprenorphine suspension following subcutaneous administration to cats

We investigated the effects of liposome encapsulation at prolonging the systemic exposure of buprenorphine following subcutaneous administration in cats. Seven healthy male cats were dosed intravenously with 0.02 mg/kg buprenorphine solution (STD‐BUP), followed 14 days later by a subcutaneous injection of 0.2 mg/kg buprenorphine as a liposomal suspension (SUS‐BUP) containing drug molecules both in liposomes and the suspending vehicle. Buprenorphine time plasma concentration data for both dosing routes were analyzed simultaneously with four compartmental models. Goodness of fit was assessed both graphically and with the Akaike information criterion. The time‐course of intravenous STD‐BUP was biphasic, with a 4.39 h average terminal half‐life. The subcutaneous SUS‐BUP produced plasma buprenorphine concentrations above 0.5 μg/L for more than 96 h, with three distinct peaks in the first 15 h. The model with best fit comprised a central and a peripheral compartment, plus three subcutaneous absorption compartments: one of dissolved drug molecules that were absorbed through a first‐order process, and two of liposome‐encapsulated drug molecules that were transferred to the solution compartment through separate zero‐order processes. Liposomes effectively prolonged the systemic exposure of buprenorphine in cats.     

Congenital pyloric stenosis in two kittens corrected by pyloroplasty

Abstract

Extract

Rural veterinary practice faces difficulties in many parts of the world. Falling farm incomes and increasing costs have sometimes resulted in reduced use of veterinary services. There seems to be widespread agreement that an increased emphasis on preventive medicine would improve the situation for both the farmer and his veterinarian. There appear to be no commonly agreed formal criteria for the development and evaluation of health programmes, either in human or veterinary medicine, but increasing attention is being paid to the problem(1) Anon Statistical indicators for the planning and evaluation of public health programmes: 11th report of the World Health Organisations expert committee on health statistics W. H. O. Tech. Reports No. 365 1971  [Google Scholar] (12) Morris, R. S. 1969. Assessing the ecnomic value of veterinary services to primary industries. Aust. vet. J., 45: 295–300.  [Google Scholar] (14) Morris, R. S. 1975. Criteria for the design and evaluation of bovine mastitis control systems. International Dairy Federation Proceedings, 85: 395–409. In [Google Scholar] (15) Schulberg, H. C., Sheldon, A. and Baker, F., eds. 1970. Program evaluation in the health fields, N.Y.: Behavioural Publications.  [Google Scholar], In some ways the evaluation of animal health programmes should be the easier, for there are fewer ethical problems and economic criteria are of paramount importance in rural practice.     

Experimental observations on prophylactic and therapeutic vaccination against foot-rot in sheep

Extract

I have taken as my subject for this address the topic, “Change”, and will deal with two aspects of change, one the challenge of change due to new knowledge and techniques and second the change we must make in our attitude to other agricultural disciplines and ancillary veterinary personnel.     

Selenium in New Zealand pastures

In grasses and clovers the highest concentrations of selenium were found in the leaves. The selenium content of different species in spring pastures on the same soil type did not vary widely although the slower growing and more deeply rooting species contained higher levels. The concentration of selenium in a pasture varied with time of the year, the lower levels being usually associated with conditions that stimulated rapid growth of the herbage, although factors other than growth rate were also involved. Lucerne appeared to be unusual in that in some areas it accumulated much higher levels of selenium than was found in other associated species. A very wide variation in levels of selenium in pastures growing on different soils has been observed (3-1500 ng/g).

Selenium-responsive unthriftiness in grazing lambs occurred where the selenium content of spring pastures was <20 ng/g. Pastures containing >30 ng/g were apparently adequate while intermediate levels were probably marginally deficient.     

Effect of N‐Acetylcysteine Supplementation on Intracellular Glutathione,Urine Isoprostanes,Clinical Score,and Survival in Hospitalized Ill Dogs

Background

Antioxidant depletion and lipid peroxidation have been correlated with disease severity and associated with poor outcomes.

Hypothesis/Objectives

Supplementing dogs with N‐acetylcysteine (NAC) during the first 48 hours of hospitalization will increase cysteine, normalize glutathione concentrations, and decrease the degree of lipid peroxidation associated with illness.

Animals

Sixty systemically ill hospitalized client‐owned dogs and 14 healthy control dogs.

Methods

Randomized investigator‐blinded, placebo‐controlled prospective study. Dogs were randomized to treatment with NAC (n = 30) versus placebo (n = 30). Antioxidants, urine 8‐isoprostane/creatinine (IP/Cr), and clinical score were determined before and after treatment with NAC. Glutathione, cysteine, and vitamin E concentrations were quantified using high‐performance liquid chromatography. Atomic absorption spectroscopy and enzyme‐linked immunosorbent assays were used to quantify selenium and isoprostane concentrations, respectively.

Results

Ill dogs had significantly lower vitamin E concentrations (27 versus 55 μg/mL; P = .0005) as well as elevated IP/Cr ratios (872 versus 399 pg/mg; P = .0007) versus healthy dogs. NAC supplementation significantly increased plasma cysteine (8.67 versus 15.1 μM; P < .0001) while maintaining glutathione concentrations. Dogs in the placebo group experienced a statistically significant decrease in glutathione concentrations (1.49 versus 1.44 mM; P = .0463). Illness severity and survival were unchanged after short duration NAC supplementation.

Conclusions

Ill dogs experience systemic oxidative stress. Supplementation with NAC during the first 48 hours of hospitalization stabilized erythrocyte glutathione concentrations. The clinical impact of this supplementation and glutathione concentration stabilization was undetermined.     

Hyperkeratosis and other complications in animals. Chlorinated hydrocarbons as possible causative agents.

Extract

This experiment was designed primarily to compare the efficacy of two heat-concentrated synthetic medium tuberculins, one prepared from strains of Mycobacterium bovis and the other from Mycobacterium tuberculosis, when used in tuberculin testing of cattle.     

Observations on calf scours in New Zealand

Extract

Scouring syndromes constitute a major disease group in dairy calves in New Zealand.     

Mange in pigs: A survey

Extract

Mange in pigs caused by Sarcoptes scabiei var. suis is reported to be common in New Zealand, but, to the writer's knowledge, no investigation has been made of the number of infested farms in any area.