Reproductive indices and performance of captive reared grasscutters (<i>Thryonomys swinderianus Temminck</i>)

Abstract

Two male and 8 female grasscutters were severally observed and paired to characterize certain indices of reproduction as important requirements for successful propagation of the animal in captivity. Observations on some of the reproductive indices are reported. Grasscutter possesses some specialized stages of courtship and coitus that were not readily available for observation Females openly showed no receptivity to all courtship moves by male. 71% of the mating exercises were however successful, resulting in 36 youngs from 9 litters, comprising 20 females and 16 males. Mean gestation length was 163.11 ± 1.58 days (Range 152-170 days). Litter size ranged from 2 to 7 (X = 4.00 ± 0.52, n= 9). Baby grasscutters were born with eyes opened, body fully haired and teeth well developed and capable of inflicting painful bites. Mean birth weight of litters was 117.70 ± 34.08g. Male birth weights were generally heavier (X = 118.10 ± 27.70g) than females (X = 100.90 ± 27.50g). Litter size and weight at birth were negatively correlated (r = - 0.42) and not significant (P>0.05). Breeding occurred in January, March, April, June, July, November and December. About 67% of the parturition occurred at night. Breeding success among other things affirmed the feasibility of commercial rearing of the grasscutter to supplement the prevailing inadequate animal protein supply in the country.

Keywords: Grasscutter, rearing, captivity, reproduction performance