Mortality Pattern of Broiler Rabbits in an Organized Farm in Bihar, India

Broiler rabbit production is a profitable venture and practiced in many countries in the world and as well as in India also (Chakrabarti et al., 2014a). The broiler rabbit contribute to improving the nutrition and the economy of small holder families, both as a source of animal protein and as a source of extra income through sale of live animals (Chakrabarti et al., 2014b). But, mortality of animals causes a great economic loss to the farmers. The mortality pattern of animals in a farm in different months or seasons is very important clue for future strategy to combat the incidences of various diseases and for prevention also (Jamuna et al., 1995). Pasupathi et al., (2014) opined that in rabbit farming, litter size and litter weight are the important economic traits which are to be genetically improved for obtaining maximum productivity and increased profitability. However, pre and post-weaning mortality in rabbits limits the production potential and lower the income generation through rabbit farming. Therefore, maintaining higher economic efficiency necessitates higher survival rate of rabbits. Successful broiler rabbit farming depends on low mortality and maximum number of live rabbit in a year. Rashwan and Marai (2000) noticed that pre and post weaning mortality until marketing limits the crop of rabbits in kilograms and a lower income would be obtained. Lebas et al., (1988) observed that pre-weaning mortality up to 5-7% of the young as stillborn and 16-20% dies before weaning. Urosevic et al., (1986) and Peeters (1988) reported mortality rates in rabbit is 12 to 20% but, it may reach up to 50% in 4 to 8 weeks of age, while mortality in rabbits above 3 months is rare. The report of rabbit mortality in a farm due to various diseases and seasonal variation is very scanty. Therefore, the present study was undertaken to find out the incidences of various rabbit diseases and mortality in an organized institutional farm.

The present study was conducted in the experimental rabbit farm of ICAR Research Complex for Eastern Region, Patna located at 25°35'37" N latitude and 85°05’ E longitude and at an altitude of 51.8 m above mean sea level. The climate of the experimental site is semi-arid with dry hot summer and winter. May and June are the hottest months with mean daily maximum temperature ranging from 31 to 41°C. Mean annual rainfall is 1200 mm, of which 80% occurs during southwest monsoon. The mean daily pan evaporation reaches a high of 8.0 mm per day in June and a low of 1.7 mm per day in January. The institute was maintaining a broiler rabbit farm with 364 rabbit comprising Newzealand White (194) and Soviet Chinchilla (170) breed. The rabbits were reared under uniform managemental conditions by housing them individually in clean metallic cages, fitted with feeders and waterers and kept inside well ventilated shed with cemented floor or in colony system. 50% mash feeding and 50% roughage feeding was practiced. Isonitrogenous concentrate mixtures with 16% crude protein and 70% total digestible nutrients were prepared with conventional feed ingredients like maize, wheat bran, deoiled rice bran, soya bean meal, ground nut cake, rice husk, fish meal, mineral mixture, common salt and offered in morning at 9 am. The green roughages were given ad libitum at 3 pm daily. The greens were Berseem, (Trifolium alexandrinum), Dhub grass (Cynodon dactylon) and Oat (Avena sativa). Ad libitum clean drinking was provided throughout the year. Routine deworming and coccidiostat was administered regularly to prevent parasitic diseases. During the three years (October, 2011 to September, 2014) study period in total 364 rabbits were under observation. The seasonal variation viz. (pre-monsoon (March, April, May), monsoon (June, July, August), post-monsoon (September, October, November) and winter (December, January, February), in regards to mortality (seasonal classification in Bihar adopted from Chakrabarti and Kumar (2014), disease incidences, young and adults, sex variation, breed, housing system etc were recorded. The incidences of disease and mortality of rabbits were diagnosed through pathological examination and postmortem findings. The data were analysed as per Snedecor and Cochran (1995). The descriptive statistics and χ² test were used to explain the statistical significance.

Out of 364 rabbits reared in institute farm, in total 63 rabbits (17.31%) were died due to various diseases during the three years period from 2011 to 2014. Among the 17.31% animals, 10.17% were Newzealand White and 7.14% were Soviet Chinchilla rabbits. The coccidiosis (3.02%), green slime disease (2.20%), haemorrhagic tracheitis (1.92%), enteritis (1.65%), pneumonia (1.37%) and peritonitis (1.37%) were the main causes of mortality in broiler rabbits (Table 1). The other ailments that affected were ear cancer (0.82%), gastroenteritis (0.82%), stomach infection (0.82%), cardinogenic shock (0.55%), stomach impaction (0.55), kidney infection (0.55%), limb injury (0.27%), ascites (0.27%), cystitis (0.27%), abscess in abdominal cavity (0.27%), rupture of liver and gall bladder (0.27%) and Injury of eye and blindness (0.27%).
 

       
Previous workers reported that coccidiosis is an important omnipresent parasitic disease and causes high mortality in commercial farms (Coudert, 1979; Khalil, 1980; Lang, 1981; Emara, 1982; Hegazi, 1988). Cheema et al., (1990) observed hepatic coccidiosis is a fatal disease and causes death within 3 to 4 days. Sharma et al., (1996) and Risam et al., (2004) observed pneumonia and enteritis were the major causes for mortality in Angora rabbits. Lukefahr et al., (1984) found pre-waning losses due to enteritis and pneumonia. Cheeke (1987) and Gergis et al., (1992) reported respiratory ailments are common among domestic rabbits. The findings of these workers corroborate the present findings.
       
It was observed in present study that the Soviet Chinchilla rabbits were less (7.14%) affected than the Newzealand white (10.16%) (Table 2). The mortality of male rabbits (6.04%) were less than the female rabbits (11.26%) and mortality of young were higher (11.54%) than the adults (5.77%). Pasupathi et al., (2014) observed mortality pattern in New Zealand White rabbit as 9.05% in adult, 9.74% in grower and 8.47% in kits mortality in Tamilnadu whereas, Das and Nayak (1991) in Odisha (36.89%), Bhasin and Singh(1995) (35.0%), Ghosh(2009) in West Bengal(29.87%) and Thakkar et al., (2019) (38.39%) in Gujarat, reported  higher mortality in Soviet Chinchilla rabbits. Dhara et al., (2009) observed 16.13% and 7.69% mortality respectively during pre-weaning and post-weaning period among Newzealand White rabbits in West Bengal. Risam et al., (2004) reported higher mortality in young Angora rabbits in Himachal Pradesh. Das (2012) reported that breed wise higher mortality was observed in New Zealand White breed of rabbit (22.12%). Sex wise higher mortality was in female (20.48%). Age wise mortality revealed that highest mortality was in finisher (21.49%). Etiology of disease indicated that highest mortality was due to coccidiosis (5.62%).Chandra et al., (2013) found that the overall mortality of Angora rabbits in Sikkim was 37.81% and the highest mortality was recorded in young ones (26.67%). In present study the mortality of male rabbits (6.04%) was less than the female rabbits (11.26%). This may be due to rearing of more female than the male rabbits. Pasupathi et al., (2014) opined that the mortality pattern in rabbits is highly variable. In the present study better health management practices that were followed in the farm might have reduced the mortality rate of broiler rabbits.
 

       
The seasonal variation in mortality of rabbits was observed in present study. In monsoon season mortality was maximum i.e. 6.32% whereas, in post-monsoon it was 5.49%, pre-monsoon 3.02% and in winter it was only 2.47%, respectively (Table 3). Ghosh (2009) reported lowest percentage of mortality in monsoon (19.52%) and highest in summer months (33.33%) followed by winter months (26.39%). Das (2012) observed season wise highest mortality was in summer (17.90%). The present study is in contrary to the study of Ghosh (2009). These observations of present study were more or less corroborating with the study of record noted by Gulterio et al., (1988). Pasupathi et al., (2014) opined that the season of kindling also plays a vital role in survivability of the kits. Chandraet_al(2013) observed higher mortality in rainy season in Angora rabbits in Sikkim might be due to the heavy rainfall and humidity and sudden change in environment temperature and humidity leading to stress to the animals. Thakkar et al., (2019) noticed that the various environmental factors like year and season influence the mortality in rabbit kits, while mortality rate among rabbits is about 5 to 8%. Other reporters like Jamuna et al., (1995) and Ramakrishna et al., (2004) also observed similar incidence of mortality in rabbits.
 

The Soviet Chinchilla rabbits were less susceptible and comparatively better performer in regards to disease resistance. Rabbits are generally susceptible to parasitic and other diseases including coccidiosis. Periodic treatment with coccidiostat and hygiene is most essential part for a rabbit farm. Regular monitoring and health care management is prerequisite criteria for any livestock farm. A successful broiler rabbit farm should have less disease incidences and less mortality of animals. If hygiene and sanitation is properly maintained in a rabbit farm, the mortality of rabbits may be restricted to a minimum level.

The author is thankful to the Director, ICAR Research Complex for Eastern Region, Patna, Bihar, India for providing necessary facility for the research work. The present study was carried out under the institute research project entitled ‘Adaptability and management study of rabbit in Bihar (ICAR-RCER/ DLFM/ 2011/ 109) and data was compiled from institute farm records.