Hind body condition and weight in primiparous of Iberian red deer (Cervus elaphus hispanicus) with one, two or three years old at mating

Abstract

Several studies of mammals have examined the fitness consequences of the age of primiparity, due to primiparous hinds face a trade-off between reproductive effort at first breeding and body growth. Physical condition of hinds is the most important factor determining whether individuals became pregnant. In fact, in yearling hinds there is a positive effect of premating body weight on conception and the onset of puberty depends on her body weight. In addition reproductive effort at first breeding should reduce the amount of body reserves available for growth and maintenance, potentially reducing residual reproductive value.This study examined 103 primiparous hinds of Iberian red deer (Cervus elaphus hispanicus) with one (n=75), two (n=21), or three (n=7) years old at mating, from 1998 up to 2006. They were kept in a 30000 square meters opendoor in the Experimental Farm of Castilla-La Mancha University in Albacete (38° 57′ 10″ North, 1° 47′ 00″ West and 690m above sea level) and they had ad libitum access to food and water. Hinds were weighed weekly on a ± 50g electronic balance, and then they were driven to a small handling box to asses their body condition. General Linear Models were used to examine the effect of the age at first breeding on the following variables: hind weight at mating, precalving and postcalving, weight gain during gestation, weight lost at calving, mating body condition and calf birth weight. The GLMs performed showed a significant effect of hind age at first breeding on mating weight (coefficient: 7.15 ± 1.67; P <0.001), precalving weight (coefficient: 6.31 ± 1.83; P <0.01), and postcalving weight (coefficient: 6.17 ± 1.59; P <0.001), improving all of these variables with hind age. Mating body condition was affected by hind age (P <0.05) too, being greater in primiparous with one year at mating than in those hinds with two or three mating years. Also, the monthly trend in body condition during gestation was different in the three groups of hinds; in hinds with one year at mating body condition improved during two first months, beginning to decrease in the third month of gestation while in the other groups of hinds it was improving practically during all gestation.On the other hand, the minimum mating weight observed to achieve a successful reproduction was 53.5, 58.5, or 71kg in primiparous with one, two or three mating years respectively. Finally, no differences were observed between groups in weight gain during gestation, weight lost at calving or calf birth weight.