Effects of sarcoptic mange and its control with oil of Cedrus deodara, Pongamia glabra, Jatropha curcas and benzyl benzoate, both with and without ascorbic acid on growing sheep: assessment of weight gain, liver function, nutrient digestibility, wool production and meat quality.

Abstract

The aim of this study was to evaluate the therapeutic efficacy of commonly used acaricidal drugs in India and also to assess the effect of ascorbic acid as adjunct therapy in 72 growing sheep with sarcoptic mange, aged 5-6 months and weighing 20.4-31.7 kg. Eight replicates of nine animals were formed based on sex, and day 0 body weight. Drugs were applied locally on the affected parts daily and recovery changes in skin lesions were observed at the time of every application. L-ascorbic acid was administered intramuscularly. Skin scrapings were collected daily from each group and examined for the presence of mites. Body weights were measured every 10th day from day 0 to 60. Nutrient digestiblity was evaluated by studying digestibility coefficients for dry matter, crude protein, ether extract, crude fibre, nitrogen free extract, total carbohydrates and nutrient balance (nitrogen, calcium and phosphorus) for a 30-day period. The liver function was evaluated by bromosulphophthalein (BSP) dye retention time. The animals were shorn on day 60 post-treatment (PT). Meat quality assesment was carried out by killing sheep at 60 days PT and estimating pH, water-holding capacity (WHC), tenderness, muscle colour, rib eye area and fat thickness. The lambs treated with oil of Jatropha curcas ascorbic acid had significantly (P < 0.05) greater mean daily body weight gains (63.29 g) than the infected untreated control (41.10 g). This was also higher than the mean daily weight gain in other treated groups. Infected untreated sheep showed significantly (P < 0.01) reduced digestibility coefficients for dry matter, crude protein, crude fibre, ether extract and total carbohydrate, but no significant differences for nitrogen-free extract. Treated sheep had significantly higher positive nitrogen, calcium and phosphorus balances compared with infested untreated sheep. Oil of J. curcas plus ascorbic acid (OJC-AA) treated group was better over all other treated groups with respect to nutrient digestibility. The BSP test revealed significant (P < 0.05) increase in BSP retention time in sheep with sarcoptic mange. Post -treatment, the BSP retention time decreased in all treated groups and the decrease was maximum in OJC-AA treated group. The carcasses of sheep treated with OJC-AA had significantly (P < 0.01) higher water holding capacity, rib eye area and back fat thickness than the untreated infected control group. The muscle pH and tenderness values were significantly lower in OJC-AA treated group post-slaughter than infested untreated control group. Muscle colour of OJC-AA treated group was maximum bright red. The lambs treated with OJC-AA had significantly (P < 0.05) greater clean fleece weight and fleece yield than the untreated infected group. It is concluded that OJC was the better therapy for sarcoptic mange of sheep and ascorbic acid as adjunct therapy is advisable. OJC-AA therapy may be better from the point of view of improving two most important production parameters in sheep, that is, wool yield and meat production.