MORPHO-BIOMETRICAL STUDY OF ROVE GOATS - III - HORNS LENGTH (HL) IN BOTH SEXES AND INDEXES OF SEXUAL DIMORPHISM OF HORNS (ISDH)

In a flock of Rove goats based in the Maures region, at Le Plan de Suv iere, parish of Collobrieres, Department of Var (South of France) the growth curves of horn length (FIL) from 75 females and 11 males have b een studied using a monomolecular mathematical mode which describes th e phase of decreasing growth. The equation of the model is X = A-Be-kt X being the measure of the parameter, k the rate of relative growth, A the ordinate of the asymptote and B a constant such as (A-B) = X(0). In the previous article of the series [3, 11], it was shown that the asymptotic value A could be taken as the practical value at maturity f or each measurement. For HL, this asymptotic value A can also be used at least provisionally as a practical value at maturity, by default. T he length of hems at maturity in Rove males (90.2 cm) is higher than i n buch of the Montecristo breed (50 to 60 cm) but below that of Pyrene an Ibex (Capra pyrenaica) from 2 Spanish populations (respectively 117 and 103 cm). On the contrary in the females one obtains respectively 29 and 17 cm in Ibex versus 44 cm in the Rove. Two indexes of sexual d imorphism of hems have been defined : ISDHA = A(male)/A(female) and IS DHk = k(male)/k(female) for the length of horn at maturity and for the rate of growth. The indexes are higher in Ibex (6.01 and 0.69 for res pectively IDSHA et IDSHk) than in Rove (respectively 4.09 and 0.26). B ecause of their observed wide ranges of variation Horn Length (HL) and indexes of sexual dimorphism of horn (ISDH) may be of interest to dis criminate biometrically species of the genus Capra and breeds of domes ticated goats.