A study on the performance of fryer rabbits under different systems of rearing

P Jaya Laxmi, B Ramesh Gupta, M Gnana Prakash, B Ekambaram and P Amareswari

Department of Animal Genetics and Breeding, College of Veterinary Science, Rajendranagar, Hyderabad, India
drprasad_vet@yahoo.co.in

Abstract

Rabbits belonging to four genetic groups were utilized to study their preweaning performance and post weaning performance under two rearing systems viz. cage system and backyard system(a low cost housing system). Analysis of variance of the preweaning litter weights and litter sizes revealed significant differences between the genetic groups.

The overall means for litter weight at birth and weaning were 281 and 1296g respectively and 5.52 and 3.81 for the litter size at birth and weaning respectively. Among the four genetic groups the litter weights and litter sizes were lowest in APAU-fawn while the litter weights and litter sizes of the other 3 genetic groups viz., New Zealand White, Flemish Giant and Soviet Chinchilla were higher but did not differ significantly among themselves. Post weaning body weights revealed significant effect of genetic group on the body weights at 4, 6, 8 and 16 weeks of age. The fryers reared in backyard system were heavier by 70 gms (12.3%) over their counterparts grown in cages at 6 weeks of age. Even at the age of 4, 8, and 16 weeks, the fryers reared in backyard weighed heavier than those kept in cages, although the difference was statistically not significant. All the interaction effects studied were not significant indicating that both sexes of all the breeds are equally suitable for backyard system of rearing.  

Hence this preliminary study on backyard rabbit rearing in Andhra Pradesh have given encouraging results to recommend backyard system of rearing which is a low cost / low investment enterprise for the farmer to improve the nutritional status of the family and also to obtain some supplementary income.

Key words: back yard housing, body weight, genetic groups, systems of rearing

Introduction

Rabbits are becoming increasingly popular as an additional source of animal protein to meet the ever increasing demand from the ever growing human population. Rabbits have several advantages as a meat producing animal in view of their smaller body size, high prolificacy, shorter generation intervals and ability to convert low quality roughages into nutritious meat (Cheeke 1986), which is tender, delicious, rich in Omega-3 fatty acids and low in cholesterol fats (McCroskey 2000).

The fryer rabbits (bunnies ear marked for selling for meat) are traditionally reared in cages after weaning age of four to six weeks, until the market age of 12 to 16 weeks.  If, such fryer rabbits are reared in groups under backyard system (a low cost housing system), the cost on pucca sheds and cages can be minimized. Thus the net profit from fryer rabbit rearing can be increased. The information on growth performance of fryer rabbits reared in backyard system in comparison with those reared traditionally in wire mesh cages is scanty. Therefore, the present study on the performance of four fryer rabbit breeds reared under backyard system and in cages was undertaken to compare their post weaning body weights.

Materials and methods 

Data on 67 litters for pre-weaning performance and on 171 bunnies for post weaning body weights belonging to New Zealand White, Flemish Giant, Soviet Chinchilla and APAU-fawn (a synthetic breed under selection for its fawn colour) born during May to November 2006 were utilized. The data on litter weights were recorded at birth and weaning (4 weeks age) while, the post weaning body weights were obtained at 6, 8 and 16 weeks of age. The litter and body weights were measured using a digital weighing balance with an accuracy of 0.1g. 

At weaning time, about 50 per cent of the bunnies of a litter were randomly chosen for rearing in backyard system and the remaining were reared in cages. In the backyard system, the rabbits were left freely in a chain link mesh enclosure with thatched roof that is similar to the backyard of a house with the enclosure. The enclosure measuring 15 x 30 ft was used to rear 30 bunnies in the present study. Care is taken to see that the bunnies are provided with sufficient space to move and to have access to the complete pen freely.  In the cage system, the bunnies were given a space of 1 sq ft/weaned bunny until the age of 16 weeks. The bunnies were placed in Californian type cages (step cages) measuring 3ft x 2ft with a height of 1.5 ft.. Six bunnies were placed in each cage such that 1 square feet floor area was given to each weaned bunny in the cages.  The concentrate feed comprising of ground Maize, Groundnut cake and wheat bran in the ratio of 2:1:1 was fed ad libitum in feeding troughs made of mud to the weaned bunnies. To take care of mineral and vitamin deficiencies, 1kg of mineral and vitamin mix was added to every 100 kg of concentrate feed. In addition, fresh cut Lucerne green fodder was fed daily and was made available throughout the day.

Concentrate feed and water was provided to the bunnies all the time in feed and water troughs both in cage as well as backyard system. No medicine was used on any of the bunny during the experimentation period.  The effects of genetic group, rearing system, sex of bunny and the interactions of genetic group x rearing system, genetic group x sex of bunny and rearing system x sex of bunny were studied as per Snedecor and Cochran (1986).

Results and discussion 

Analysis of variance of the pre-weaning litter weights and litter sizes revealed significant differences between the genetic groups (Table 1).

The mean litter weights and litter sizes at birth and at weaning according to the genetic groups are presented in Table 2.

The overall means for litter weight at birth and weaning were 281 and 1296g respectively and 5.52 and 3.81 for the litter size at birth and weaning respectively. Among the four genetic groups the litter weights and litter sizes were lowest in APAU-fawn, which was a synthetic breed under selection for its fawn colour, while the litter weights and litter sizes of the other 3 genetic groups viz., New Zealand White, Flemish Giant, Soviet Chinchilla  were higher but did not differ significantly among themselves.

Results of the analysis of variance of the post weaning body weights presented in Table 3  revealed significant effect of genetic group on the body weights at 4, 6, 8 and 16 weeks of age, while the rearing system had significant influence on the body weight at 6 weeks of age only.

The influence of sex of bunny was found to be non-significant at all the ages. All the interaction effects studied were not significant.

The mean body weights of individual fryers at 4, 6, 8, 16 weeks of age along with their standard errors are detailed in Table 4.

The mean body weights at 4, 6 and 16 weeks were  highest in APAU-fawn, a synthetic breed evolved by crossing  New Zealand White, Grey Giant and Local White rabbits followed by Flemish Giant, New Zealand White and Soviet Chinchilla. The higher body weights in APAU fawn could be due to the smaller litter size both at birth and at weaning since the bunnies born in smaller litters get more milk and better maternal care during their pre-weaning period, resulting in better pre-weaning growth and consequently, weigh higher during post-weaning period also, in comparison to those born in larger litters. The higher body weights in APAU-Fawn could also be attributed to hybrid vigor.

Results of the present study indicated that there are significant differences among the breeds in their body weights at  4, 6, 8 and 16 weeks of age in both cage and backyard rearing systems indicating the significant variation in the genetic makeup of these genetic groups, offering scope for selection for improved body weights. The rearing system was found to have significant effect on the body weight at 6 weeks age but not at the other ages studied. The fryers reared in backyard system were heavier by 70 gm (12.3%) over their counterparts grown in cages at 6 weeks of age. Even at the age of 4, 8, and 16 weeks, the fryers reared in backyard weighed heavier than those kept in cages, although the difference was statistically not significant. The effect of sex on the body weights at various ages was also found to be non significant which revealed the absence of sex dimorphism in fryer rabbits. Since the genetic group x rearing system interaction was found to be non–significant, all the breeds are equally suitable for backyard system of rearing. Since the genetic group x sex interaction was also not significant, both the sexes are having similar body weights in all the breeds studied. Similarly, the non-significant rearing system x sex interaction indicated that both the sexes are well and equally adapted to the backyard rabbit rearing as in the cage system.  Nguyen Quang Suc et al (1996), while studying the effect of housing system (cage versus underground shelter) on performance of rabbits on farms reported higher growth rates and body weights in rabbits reared in under ground shelter, when compared to those reared in cages on account of lower temperatures in underground shelter.

A similar free-range system of rearing was reported from Uganda by Lukefahr (1998) where farmers allowed their rabbits to graze for forage on their farms during the day, and in the evening they were collected and placed in small huts(with forage provided) as a safeguard against predators and thieves. Lukefahr and Cheeke (1991) suggested that in areas, where rabbit meat is not widely consumed or marketed, small-scale rabbit projects should be initiated on a backyard family basis, since the ultimate goal of rabbit raising was to provide more meat at the family level. In the present study, it was observed that there were no specific health or managemental problems associated with backyard system.

Hence this preliminary study on backyard rabbit rearing in Andhra Pradesh has given encouraging results to recommend backyard system of rearing which is a low cost / low investment enterprise for the farmer to improve the nutritional status of the family and also to obtain some supplementary income.

References   

Cheeke P R 1986 Potentials of rabbit production in tropical and subtropical agricultural systems. Journal of Animal Science 63 1581–1856 http://jas.fass.org/cgi/reprint/63/5/1581

Lukefahr S D 1998 Rabbit production in Uganda: potential versus opportunity. World Rabbit Science 6(3-4):331-340 http://www.wrs.upv.es/files/journals/vol%206_3_4_lukefahr.pdf

Lukefahr S D and P R Cheeke 1991 Rabbit project development strategies in subsistence farming systems, FAO   World Animal Review No 69 http://www.fao.org/docrep/U5700T/u5700T0d.htm

McCroskey R 2000 Raising Rabbits in the Pacific Northwest. Canadian Centre for Rabbit Production Development. Surrey, BC Canada V4N 3T7

Nguyen Guang Suc, Dinh Van Binh, Le Thi Thu Ha and Preston T R 1996 Effect of housing system (cage versus underground shelter) on performance of rabbits on farms. Livestock Research for Rural Development Volume 8, Article retrieved May 17,2008 from  http://www.lrrd.org/lrrd8/4/suc84.htm

Snedecor and Cochran 1986 Statistical methods.The Iowa State Univ.press, Ames.Iowa, USA 

Received 17 May 2008; Accepted 16 January 2009; Published 5 August 2009

Go to top