Pattern of feed intake and associated metabolic and endocrine changes differentially affect postweaning fertility in primiparous lactating sows.

  title={Pattern of feed intake and associated metabolic and endocrine changes differentially affect postweaning fertility in primiparous lactating sows.},
  author={Louisa J Zak and John R. Cosgrove and Frank Xavier Aherne and George R. Foxcroft},
  journal={Journal of animal science},
  volume={75 1},
Effects of differential patterns of feed intake during lactation, associated metabolic and endocrine changes, and reproductive status after weaning were investigated in 26 primiparous sows suckled by six piglets. Sows were fed to appetite (Group AA; n = 9) from d 1 to 28 of lactation or restricted to 50% from d 22 to 28 (Group AR; n = 9) or from d 1 to 21 (Group RA; n = 8). Sow weight, backfat, and litter weights were recorded weekly. After weaning sows were tested twice daily for onset of… 

Figures and Tables from this paper

Reproductive, metabolic, and endocrine responses to feed restriction and GnRH treatment in primiparous, lactating sows.

Although exogenous GnRH therapy restored LH secretion in feed-restricted sows, it did not improve overall reproductive performance and paradoxically, GnRH treatment in lactation seemed to suppress the expected LH and FSH responses to weaning.

Duration of lactation, endocrine and metabolic state, and fertility of primiparous sows.

Overall, embryonic survival, not ovulation rate, seems to be the limiting factor for potential litter size in the second parity, and endocrine and metabolic data indicate that the mechanisms affecting reproductive performance may differ between the two weaning systems.

Restricted feed intake in lactating primiparous sows. I. Effects on sow metabolic state and subsequent reproductive performance.

Overall, catabolism negatively affected litter weaning weight and embryonic development of the next litter, but the extent to which individual sows used tissue mobilisation to support these litter outcomes was highly variable.

Lactation weight loss in primiparous sows: consequences for embryo survival and progesterone and relations with metabolic profiles.

Positive consequences of lactational weight loss in mildly feed-restricted primiparous sows for embryonic survival are shown and it is shown that these consequences seem only mildly related with metabolic alterations during lactation and not with metabolic alteration during subsequent gestation.

Selective protein loss in lactating sows is associated with reduced litter growth and ovarian function.

It is suggested that no decline in lactational performance or ovarian function when a sow loses approximately 9 to 12% of its parturition protein mass, however, progressively larger decreases in animal performance are associated with a loss of larger amounts of body protein mass at parturitions.

Protein (lysine) restriction in primiparous lactating sows: effects on metabolic state, somatotropic axis, and reproductive performance after weaning.

Evidence is provided that protein (lysine) restriction throughout lactation alters circulating concentrations of somatotropic hormones and insulin at the end of lactation and has a negative impact on postweaning ovulation rate.

Effects of pre-weaning energy substitutions on post-weaning follicle development, steroid hormones and subsequent litter size in primiparous sows.

It is suggested that increasing circulating insulin and glucose concentrations during late lactation or a week of metabolic recovery positively improves subsequent litter size in primiparous sows.

Influence of feed intake during pregnancy and lactation on fat body reserve mobilisation, plasma leptin and reproductive function of primiparous lactating sows.

Increased feed intake during pregnancy increased live weight, backfat thickness, and estimated body lipid and protein on days 4 and 25 of lactation and resulted in lower feed intake and higher lipid mobilisation during lactation without a detrimental influence on milk production.

Effects of feeding level during lactation on FSH and LH secretion patterns, and follicular development in primiparous sows.

It is demonstrated that feed restriction of primiparous sows during lactation affects not only LH, but also FSH, as well as lactational follicular growth.

Dietary energy source at two feeding levels during lactation of primiparous sows: II. Effects on periestrus hormone profiles and embryonal survival.

It is concluded that altering feeding level during lactation or dietary energy source from farrowing until d 35 of subsequent pregnancy did not affect embryonic development and embryonal survival.



Effect of restriction of energy during lactation on body condition, energy metabolism, endocrine changes and reproductive performance in primiparous sows.

It is concluded that restriction of feed intake during lactation affected body condition and metabolism of primiparous sows, but reproductive performance and productivity were not affected.


As expected, low-level feeding in lactation resulted in a greater body weight and backfat loss and peak LH levels achieved after UnKH injection did not differ significantly.

Relationship between lactation-associated body weight loss, levels of metabolic and reproductive hormones and weaning-to-oestrous interval in primiparous sows.

The group of sows with higher weight loss during lactation tended to have a higher farrowing weight and higher pre-weaning plasma prolactin levels, especially at weaning, and the L-gr sows had higher plasma insulin and lower plasma cortisol concentrations, especially when compared with H-Gr sows.

Effect of feed intake during lactation and after weaning on sow reproductive performance

To study the effects of feed intake during lactation and after weaning on reproductive performance, 89 second-parity Lacombe sows were allowed 6 kg feed d−1 (H) or were restricted to 3 kg feed d−1

Enhancement of ovulation rate in gilts by increasing dietary energy and administering insulin during follicular growth.

It is concluded that increases in ovulation rate produced by dietary energy and insulin are not necessarily accompanied by changes in gonadotropins or estradiol.

Effect of nutrition on embryonal mortality in gilts: association with progesterone.

The timing of the change in feed allowance after mating is crucial for demonstrating effects of nutrition on embryonal survival in gilts, and progesterone may mediate these effects.

Effect of delayed breeding on the endocrinology and fecundity of sows.

Litter size increased by breeding Parity 1 and 2 sows at second rather than at first estrus, and predicted changes in fat and protein during lactation, in the absence of any significant changes in sow weight or backfat During lactation and between weaning and breeding.

Nutritional and lactational regulation of fertility in sows.

  • G. Foxcroft
  • Biology, Medicine
    Journal of reproduction and fertility. Supplement
  • 1992
Data from studies involving treatment with exogenous gonadotrophins or luteinizing-hormone-releasing hormone (LHRH) indicates that ovarian sensitivity is not compromised during lactation in sows, and there is still very little direct evidence for the mechanisms by which the metabolic state of lactating sows affect fertility after weaning.