Goat placental efficiency determination by comparing litter weight to the surface area of the cotyledons
S. Ocak, S. Ogun, Z. Gunduz, H.Onder
Anim Reprod, vol.12, n4, p.920-926, 2015
Abstract
The relationship between placental component weights and litter related factors was investigated in 81 Damascus goats. The aim was to extensively compare cotyledonary traits to ascertain the main influencial factors in placental efficiency (PE). Every cotyledon in the placenta was measured for surface area, weight and depth in order to link any possible correlations to birth weight (BW), birth type (BT) and sex. Twins, especially the mixed gender ones, were shown to have far more efficient placentas than singletons. A new efficiency parameter, cotyledon efficiency (CE) was used to measure the effectiveness of the cotyledons to further understand PE. A Newly adopted method was used to measure the individual and total surface area of all the cotyledons on the placenta of each animal, rather than just determining the total number and weight of the cotyledons. Where in earlier studies it was thought that cotyledon number was the main factor affecting litter weight (LW) and consequently kid survivability, this study showed that the size of the cotyledons and their surface area interrelationships were a feature with far more influence in the placental exchange, producing heavier and healthier offspring. Birth type significantly affected (P < 0.001) BW, LW, placental weight (PW), and total cotyledon surface area (TCSA). High positive correlation (r = 0.75) was observed between CE and PE. This association was affected by BT, where the correlation remained high for twins (r = 0.829) and poor (r = 0.470) for singles. A strong negative correlation (r = -0.79) was seen between CE and TCSA. Results indicated that the total weight of the cotyledons, whilst an integral component of the placental weight, was not the main indicator of its efficiency but its surface area was, suggesting that larger cotyledons were far more efficient than the equivalent sum of smaller cotyledons. Further investigation is needed to ascertain the main factors influencing the promotion of larger cotyledons in the placenta
Keywords
cotyledon efficiency, goats, litter weight, placenta weight.