Cria alpaca body weight and perinatal survival in relation to age of the dam

The present study with alpacas determined effect of dam's age on body weight and survival of cria during the first week of life. Pregnant dams (n = 424) and their crias were used in the study. Cria body weight (kg) was determined at time of placenta expulsion. Placenta weight and larger width were measured immediately after expulsion. Crias were monitored for the first week and a necropsy was performed if death occurred. Data were analyzed using analysis of variance. The body weight of crias at birth, the weight, and the largest width of placenta increased with age of the dam (P < 0.05), reaching a peak at 9 years and then declined progressively. Placental efficiency also increased with the dam's age, and showed a bimodal shape, peaking at 6- and 11-year-old dams (P < 0.05). Altogether, 398 crias survived and 26 died; of those 6 died of starvation, 5 of hypothermia, 4 were stillborn and the rest from other miscellaneous causes. More crias died from 2-year-old dams than from dams of any other age (P < 0.05). In addition, dead crias had lesser body weights (6.4 kg) than those of crias that survived (7.8 kg, P < 0.05). The weight and width of the placenta was similar for live and dead crias.