Effect of protective coats on physiological parameters of Angora goats exposed to cold, wet and windy conditions

 

J.H. Hoon, M.A. Snyman* & M. van Heerden

Grootfontein Agricultural Development Institute, Private Bag X529, Middelburg (EC), 5900, South Africa

*Email: Gretha Snyman

 

High mortality rates of Angora goats during periodic cold climatic spells cause considerable annual monetary loss in the mohair industry. Various measures are taken to prevent losses during cold spells, of which kraaling of goats in sheds is the most common practice. However, the extensive nature of Angora goat farming and the new labour legislation decreased the viability of this practice. Other practices to prevent losses have been done in the past, with varying success rates. Some Angora goat producers have also made use of coats for protection against the elements. The aim of this study was to determine the effect of protective coats on rectal, skin and subcutaneous temperature, heart rate, respiratory rate, shivering score and serum glucose level of Angora goats exposed to cold, wet and windy conditions. The study was conducted at the Grootfontein Agricultural Development Institute on 24 ten-month-old castrated male Angora goat kids during 2009 and on 30 nine-month-old castrated male Angora goat kids in 2010. For the 2010 trial, temperature data loggers were implanted under the skin on the back between the shoulder blades of all animals. The data loggers recorded half-hourly subcutaneous temperatures for a two-month period from middle June to middle August 2010. Rectal temperature of animals in both the Coats and Control groups declined during both the 2009 and 2010 cold stress trial periods. Rectal temperature of the Coats group was 1.91 °C higher (36.49 ± 0.45) than the Control group (34.58 ± 0.45; P<0.05) at the end of the trial in 2009. Coats group animals showed, on average, a 2.21 °C less drop in rectal temperature than the Control group (P<0.05). A similar trend was observed in 2010. Differences were also obtained in skin temperature between the two groups. The most pronounced difference was between skin temperature recorded on the shoulder and britch. The Coats group animals had higher skin temperatures on their shoulders and britches over the entire trial period (P<0.05). Their shoulder skin temperature increased by 0.85 °C over the trial period, while that of the Control group decreased by 1.24 °C. The animals protected with coats had much lower daily temperature amplitudes than the Control group animals during the early days of the 2010 trial, when they were just shorn. As the hair length increased, the differences in daily amplitude between the groups diminished. After four weeks’ hair growth, there were no significant differences in subcutaneous temperatures of Coats and Control group animals. Animals in both the Coats and Control groups showed an increased heart rate over the first two hours of the trial, after which it decreased to below the initial values at the end of the trial period. Serum glucose levels of animals in both groups showed a marked drop towards the end of the trial period to 1.33 ng/ml and 1.66 ng/ml in the Coats and Control groups respectively. It is concluded that the coats provide sufficient protection to newly shorn Angora goats during adverse weather conditions for it to be implemented in practice.

 

Published

Proceedings 45th SASAS congress, East London