Growth and reproductive performances of New Zealand White and Hyplus rabbits raised in Ninh Binh province of Vietnam
 

Mai Thi Thom¹, Dinh Van Binh², Nguyen thi Huyen¹, Nguyen Xuan Trach¹

¹ Hanoi University of Agriculture, Gialam, Hanoi, Vietnam

² Goat and Rabbit Research Center, Son Tay, Hanoi, Vietnam

 

Abstract

A study was conducted to compare growth and reproductive performances of rabbits of two breeds, viz. New Zealand White and Hyplus, which were raised in a new rabbit breeding farm in Ninh Binh province (Vietnam). Growth was observed from weaning (30 days of age) to 90 days of age by weghing 35 heads of each breed every ten days. Reproductive performance was evaluated in terms of age and weight of the doe at first estrus and at first mating, conception rate, estrous cycle length, gestation length, and number of litters/doe/year. Litter parameters included number born per litter, live births per litter, litter size at 21 and 30 days of age, litter weight at birth and average weight at birth, at 21 and 30 days of age, and survial rate to weaning. Results showed that New Zealand White and Hyplus rabbits grew normally under the local conditions with the ADG being highest for the period of 30-40 days of age (54.99 and 55.56g/head/day, respectively), then gradually going down. From 40 days of age afterward Hyplus rabbits had higher ADGs compared to New Zealand White rabbits (P<0.05). The two breeds also showed normal reproductive performances with Hyplus performing better than New Zealand White in most of the observed litter parameters (P<0.05).

Key words: Growth, Hyplus, New Zealand White, rabbits, reproduction

Introduction

With the efficient use of forage based diets, combined with their capacity to produce multiple offspring of rapid growth, rabbits have a tremendous capacity to produce animal protein for human consumption without competing for grains as fossil fuel costly feed (Leng, 2006). Therefore, more and more research and development activities have been undertaken to improve rabbit production in Vietnam in order to meat the growing demand for meat and to make better utilization of local resources for sustainable rural development (Dinh Van Binh, 2002, 2008). A number of exotic rabbit breeds from different sources have been introduced into the country. Evaluation of performances of the introduced exotic rabbit breeds kept under the local physical and husbandry conditions would be of significance for appropriate breeding as well as feeding strategies. The present paper reports a study on growth and reproduction of New Zealand White and Hyplus rabbits which have been raised in a rabbit breeding farm recently established in Ninh Binh province (Vietnam).

Materials and methods

New Zealand White and Hyplus kids were weaned at 30 days of age and thereafter were fed on a diet comprising grown forages and a commercial compound pelleted feed produced by Goyomarch-NIAH Ltd. The pellets contained 2550 Kcal ME, 16% CP and 11% crude fiber. The growing rabbits from 31 to 90 days of age were weighed individually every ten days before the morning feeding for growth study in terms of liveweight and average daily gain (ADG).

Reproduction of the doe was assessed in terms of age and weight at first estrus and at first mating, conception rate, estrous cycle, gestation, and number of litters/doe/year. Litter parameters included number born per litter, live births per litter, litter size at 21 and 30 days of age, litter weight at birth and average weight at birth, at 21 and 30 days of age, and survial rate to weaning.

Heat detection was made by direct observation twice per day at 8am and 4pm. Natural mating was applied on detection of heat. Pregnancy was dignozed by manual palpation on days 12 of mating. The doe was weighed at first estrus and first mating.

Data were subjected to t-student test to make comparison between the two breeds for each observed parameter.

Results and Discussion

Growth

Liveweight data presented in Table 1 show a normal growth pattern of the two rabbit breeds. Of the two, Hyplus always showed a heavier liveweight and the difference became statistically significant (P<0.05) and larger and larger from 50 days of age afterward.

According to Dinh Van Binh (2004), New Zealand White rabbits raised in Son Tay (Hanoi) weighed 700, 2000, and 2800g at 30, 60, and 90 days of age, respectively. That is the New Zealand White rabbits raised in Ninh Binh showed their lighter liveweights. It may be due to a fact that the young rabbits had been born during a spell of very cold weather at the beginning of 2008 and also because of that cold weather the mother rabbits had not received enough green forage to produce enough milk for the kids.

The average daily gain (ADG) of the two breeds was gradually reduced over periods of time since weaning. In all of the periods of observation, Hyplus rabbits had higher ADGs than New Zealand rabbits. Except for the first ten days, the diference in ADG in the other periods was statistically significant (P<0.05).

Reproduction

The observed reproductive parameters of the doe are given in Table 3, which shows that does of the two breeds exhibited normal reproductive physiology (Dinh Van Binh, 2002). Hyplus does had significantly higher age and weight at first estrus. Gestation was longer in Hyplus does (31.43 vs 30.7 days, P<0.05). Other parameters (estrous cycle, age and weight at first mating, conception rate, and number of litters/doe/year) were not significantly different between the two breeds (P>0.05).

Table 4 shows normal litter parameters of the two breeds in terms of number born per litter, live births per litter, litter size at 21 and 30 days of age, litter weight at birth, at 21 and 30 days of age. However, the survial rate was low, making the litter size reduced over time up to weaning. The survival rates (78.52% and 79.01%) were lower than those previously reported by Dinh Van Binh (2002) being 83-85.7%. This may be due to the spell of chilly weather at the beginning of 2008. All of the observed parameters were higher in Hyplus compared to New Zealand White with most comparisons being statistically significant (P<0.05).

Conclusions

From the above observations it can be concluded that

New Zealand and Hyplus rabbits showed fairly good growth under the local conditions of Ninh Binh rabbit breeding farm with the ADG being highest for the period of 30-40 days of age (54.99 and 55.56g/head/day, respectively) and gradually going down thereafter. From 40 days of age onward Hyplus had significantly higher ADGs compared to New Zealand White (P<0.05).

The two breeds of rabbits showed normal reproductive performances under the local conditions with Hyplus performing better than New Zealand White in most litter parameters (P<0.05)

References

Dinh Van Binh 2002: Achievements over 20 years of rabbit production research and development. Proceedings of the scientific workshop to commemorate 50^th anniversary of the National Institute of Animal Husbandry (NIAH) of Vietnam. Agricultural Publishing House. Hanoi

Dinh Van Binh 2004: Annual Scientific Report. Goat and Rabbit Research Center. Sontay. Hatay.

Dinh Van Binh 2008: Research and development projects of rabbits in Vietnam. Proceedings of the International Workshop on organic rabbit farming based on forages, held on 25-27 November 2008, Cantho University, Cantho City, Vietnam.

Leng R A 2006: Digestion in the rabbit-a new look at the effects of their feeding and digestive strategies.  Workshop-seminar on "Forages for Pigs and Rabbits" MEKARN-CelAgrid, Phnom Penh, Cambodia, 22-24 August,  2006. Article # 18. Retrieved October 7, 2008, from http://www.mekarn.org/proprf/leng.htm.

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