Effect of flaxseed supplementation on metabolic state,endocrine profiles,body composition and reproductive performance of sows

Objective:To assess the effect of flaxseed supplementation on metabolic profile,endocrine concentrations,non-esterified fatty acids(NEFA),body composition variables,and reproductive performance of sows.Methods:All the 21 crossbred Large White Yorkshire sows were considered in the study period starting at day 1 of current farrowing when the feeding of specific supplemental ration was started until the day of subsequent farrowing(days 150-155)and were equally allocated into three groups.Group 1 served as the control group and followed their normal feeding schedule.Group 2 and group 3,in addition to their normal feeding schedule,were supplemented with flaxseed at a rate of 0.5%and 1.0%of the dry matter,respectively.Blood samples were collected 15 days prior to farrowing,on the day of farrowing(day 0),at weekly intervals until day 28 of lactation and at monthly intervals during gestation to harvest the plasma.Plasma was used to assess the metabolic and endocrine status of sows.Body weight of each sow and individual birth weight of all piglets born were measured.Results:Flaxseed supplementation led to decrease in plasma cholesterol and triglyceride levels in the supplemented groups than in the control group(P<0.05).Plasma estradiol-17βlevel was higher in group 2 than that in group 1 and 3 on day 90 of the gestation period(P<0.05).The mean plasma level of insulin-like growth factor 1 was higher in group 3 than that in group 1 and 2 both in late lactation(day 28)as well as in early gestation(day 30)(P<0.05).Plasma NEFA and weight gain were greater in sows of group 2 and 3 compared to those fed with the normal control diets(P<0.05).The proportion of pregnant sows relative to sows bred was 100.0%in group 2 and 3 and 85.7%in the control group.Piglet mortality was lower in group 2 and 3 compared to group 1(P>0.05).Conclusions:Flaxseed improves endocrine profiles,NEFA concentrations and body weight,resulting in better pregnancy rate and litter size.

Heritabilities and genetic and phenotypic correlations of litter uniformity and litter size in Large White sows

Litter uniformity, which is usually represented by within-litter weight coefficient of variation at birth （CVB）, could influence litter performance of sows and the profitability of pig enterprises. The objective of this study was to characterize CVB and its effect on other reproductive traits in Large White sows. Genetic parameters and genetic correlation of the reproductive traits, including CVB, within-litter weight coefficient of variation at three weeks （CVT）, total number born （TNB）, number born alive （NBA）, number born dead （NBD）, gestation length （GL）, piglet mortality at birth （Mo）, piglet mortality at three weeks （M3）, total litter weight at birth （TLW0）, and total litter weight at three weeks （TLW3） were estimated for 2 032 Large White litters. The effects of parity and classified litter size on CVB, CVT, TNB, NBA, NBD, GL, M0, M3, TLW0, and TLW3 were also estimated. The heritabilities of these reproductive traits ranged from 0.06 to 0.17, with the lowest heritability for CVB and the highest heritability for TLW0. Phenotypic and genetic correlations between these reproductive traits were low to highly positive and negative （ranging from -0.03 to 0.93, and -0.53 to 0.93, respectively）. The genetic correlations between TNB and CVB, and between M0 and CVB were 0.32 and 0.29, respectively. In addition, CVB was significantly influenced by parity and litter size class （P〈0.05）. All the results suggest that piglet uniformity should be maintained in pig production practices and pig breeding programs.