Intergenerational effects of omega-6 fatty acids. 1. The reproductive rate of Border Leicester × Merino ewes is influenced by the diet fed to their dams around conception

The proportion of female lambs was previously higher when Merino dams were fed a diet high in omega-6 (n-6) based on oats and cottonseed meal compared with low in n-6 based on silage around mating. The effect of maternal diet on the reproductive success of the female offspring from these dams has not previously been examined. The aim of the present study was to determine whether the reproductive rate of Border Leicester × Merino ewes was higher when their Merino dams were previously fed a diet high in n-6 compared with low in n-6 around conception. Merino dams were fed diets based on either silage low in n-6 or oats and cottonseed meal high in n-6 fatty acids for ~40 days pre-mating only or 40 days pre-mating and 17 days post-mating in each of 2 years. The reproductive performance (proportion pregnant and fetuses conceived) of their Border Leicester × Merino ewe offspring born in each year was examined at their first mating. Ewe lamb birthweight and fat score at the time of mating was not significantly affected by the diet fed to their dams around mating. The proportion of Border Leicester × Merino ewes pregnant was not different, however the number of fetuses per ewe was significantly (P = 0.002) higher when their dams were fed a High n-6 compared with a Low n-6 diet around mating (1.64 ± 0.05 vs 1.42 ± 0.05 fetuses/ewe pregnant, respectively). The reproduction rate of ewes may be affected by diet fed to their dams in the peri-conceptional period and could be associated with fetal programming.

The influence of peri-conception and first trimester dietary restriction of protein in cattle on meat quality traits of entire male progeny

Primiparous Santa Gertrudis heifers were used to evaluate the effects of gestational dietary protein content on meat quality traits of 20month old bull progeny (n=40). At -60d before AI, heifers were randomly allocated to HIGH or LOW protein diet (HPERI and LPERI). From 24dpc, half of each treatment group changed to an alternative post-conception HIGH or LOW protein diet (HPOST and LPOST). LPERI and LPOST diets resulted in higher shear force of the semitendinosus muscle than HPERI (P=0.053) and HPOST (P=0.003), respectively. Heat-soluble collagen in the semitendinosus muscle was lower (P=0.019) for LPERI than HPERI. Collagen and tenderness of the longissimus muscle were not affected by dam nutrition (P>0.05). Color, pH, sarcomere length, cooking loss, compression values, desmin and troponin-T degradation, fiber type, intramuscular fat and polyunsaturated fatty acid content were not affected by dam nutrition during the peri-conception and first trimester gestational period (P>0.05).