Effect of Feeding Fat and Altering Weaning Schedule on Rebreeding in Primiparous Sows

Abstract

Primiparous sows that farrowed on a commercial farm during late summer in 1980 (n = 65) or late winter in 1981 (n = 62) and lactated 3 to 4 wk were used. Sows were assigned in a factorial experiment to one of two lactation diets (control or 10% fat-supplemented) and one of three periods (0, 2 or 5 d) of early weaning of the heaviest one-half of the litter. Days from weaning to estrus averaged 16.7 +/- 1.5 and 8.7 +/- 1.6 in summer and winter, respectively, and the season X diet interaction was significant for days from weaning to estrus and percentage of sows that exhibited estrus after weaning. In summer, supplementing diets with fat reduced the weaning-to-estrus interval from 20.9 +/- 2.1 to 12.6 +/- 2.1 d and increased percentage of sows in estrus by 10 d postweaning from 34 to 59. In winter, days from weaning to estrus tended to be greater and percentage of sows in estrus by 10 d postweaning tended to be less in sows fed fat-supplemented diets (10.3 +/- 2.5, 74%) than in sows fed control diets (7.1 +/- 2.9, 82%). Over both seasons, weaning one-half the litter 2 d early (2-d group) increased the percentage of sows in estrus by 10 d after weaning (77%) compared with 5-d (58%) or 0-d (51%) groups. Total litter weight at weaning was not affected by season, diet or days with one-half litter. However, piglets of lightest weight remaining on sows two or five extra days gained .09 +/- .03 kg/d more than lightest weight pigs in control (0-d) litters over the same interval. Early weaning of heaviest pigs may improve reproductive performance of primiparous sows in summer and winter, while supplementing lactation diets with fat may improve performance in summer, when weaning-to-estrus interval is longer than in winter.

Effects of Adding Fat to the Sow Lactation Diet on Lactation and Rebreeding Performance

“…Weekly metabolizable energy (ME) intake tended to be higher during wk I and 3, and was higher (P<.04) during wk 2 for sows fed diet F. No seasonal differences were noted for weekly feed intake, total feed intake or weekly ME intake. These results are consistent with work reported by Seerley et al (1981)in which no differences were noted in feed intake between sows fed control, 10% supplemental corn oil or 10% supplemental animal fat diets, and with ,~ work reported by Cox et al, (1983) where 10% dietary fat supplementation and season had no Z effect on daily feed intake. Added fat in the lactation diet increased daily ME intake in sows ,~ (Stahly et al, 1980).…”

“…Average weekly high temperature in the farrowing facility was approximately 3.0 C higher (P<.001) during the summer season (X=26.9 C) than during the winter season (X=23.8 C), which is slightly higher (2.3 C) r~ than the average daily high temperature in farrowing rooms between seasons reported by Cox et al (1983). Furthermore, average weekly temperature was an average of 1.8 C higher e~ (P<.001) (X=24.2 vs 22.4 C) and average z weekly temperature range was 2.7 C greater e~ (P<.001; X=5.5 vs 2.8 C) during S than in W. m m u, The higher average weekly temperature range is probably not of the magnitude necessary to affect feed intake, but may have affected lactation and rebreeding performance of sows due to a higher level of stress produced from Z higher environmental temperatures or wider Z temperature fluctuations in the farrowing o facility.…”

“…Sows fed diet C lost 10.8 kg; sows fed diet F lost 11.2 kg from <~ farrowing to weaning but sows tended to lose more weight during the lactation period in S (13.7 kg) than W (8.2 kg). Cox et al (1983) indicated that fat supplementation in the sow lactation diet had no effect on reducing weight loss during the summer, but during the winter, sows fed the 10% fat-supplemented diet lost more weight than sows fed the contrOl diet. However, Cox et al (1983) indicated that supplementing the diet with fat reduced the number of days to estrus following weaning in summer, but did not affect this interval in winter.…”

“…Further studies have indicated a reduction in farrowing rate ) and a lengthening of the rebreeding interval (Fahmy et al, 1979) during the summer. Cox et al (1983) observed a decrease in the weaning-to-estrus interval in sows fed diets containing 10% added fat during the summer months, while the addition of fat to the sow lactation diet had no effect on the interval from weaning to rebreeding during the winter.…”

“…Accepted October 15, 1985. 1982aCox et al, 1983;Kornegay and Thomas, 1983). Several researchers have studied the effects of adding fat to the sow's lactation diet on lactation performance as reviewed by Pettigrew (1981).…”