Maximising embryo production in endangered sheep breeds: in vitro procedures that complement in vivo techniques

A preliminary study of the effects of organic farming on oocyte quality in ewe lambs

This study tested whether feeding Rasa Aragonesa ewes certified organic feed, from 15 days before mating until lamb weaning, improved oocyte quality and in vitro maturation (IVM) and fertilization (IVF) performances of the offspring. In a second experiment, ovaries from ewe lambs that were bred on an organic farm and were of the same breed were compared with those from conventionally bred animals. The number (± standard error of the mean) of healthy oocytes per ewe lamb did not differ significantly between organic (12.2 ± 3.3) and conventionally (13.6 ± 4.0) fed ewes. Ovaries from ewe lambs born on an organic farm had significantly (P < 0.0001) more healthy oocytes per ewe lamb (39.6 ± 5.2) than did those born on a conventional farm (25.0 ± 4.2), and higher IVM (76.5% vs. 53.1%, P < 0.0001) and IVF (97.3 vs. 91%, P < 0.05) rates. In conclusion, this preliminary approach to the study of the effect of organic procedures on the sheep oocyte quality indicates that the total integration in the complete organic system improved the oocyte quality of ewe lambs, although organic feeding alone was insufficient to improve quality.

The effect of periconceptional undernutrition of sheep on the cognitive/emotional response and oocyte quality of offspring at 30 days of age

Maternal periconceptional undernutrition is associated with altered development and increased risks of adverse outcomes in the offspring. This circumstance is normal in flocks under extensive farming systems, which depend on natural forage resources. The aim of this study was to determine the effect of periconceptional undernutrition in sheep on behavioral and reproductive aspects of the offspring. Eighty ewes were synchronized in estrus and allocated to two groups (n=40) to be fed diets that provided 1.5 (C) or 0.5 (L) times the requirements for maintenance. Ewes were mated and 7 days later fed the control diet until lambing. One month after lambing, 32 lambs were exposed to tests to determine their cognitive and emotional responses. Six ewe lambs were euthanized and in vitro maturation and fertilization procedures were performed. L ewes presented a significant reduction in prolificacy and fecundity (P<0.05) in comparison with C ewes. Mean LW at lambing of L lambs was significantly higher than C lambs (C: 3.80 ± 0.11; L: 4.24 ± 0.15 kg, P<0.05). Lambs born from C ewes spent more time walking than L lambs (P<0.05) in the isolation test, revealing a decrease in the locomotor activity of lambs born from undernourished ewes around conception. Ewe lambs from the undernourished ewes presented a total population of oocytes 2.3 times higher than ovaries from control ewe lambs (60.0 ± 7.8 v. 140.0 ± 18.5 oocytes; P<0.05). In conclusion, periconceptional undernutrition is able to produce an increment in the body weight and the oocyte population, and an alteration of the locomotor activity of the offspring.