Fernanda Almeida and George Foxcroft
Alberta Pork Research Centre / Department of Agricultural, Food and Nutritional Science; University of Alberta, Edmonton, AB, Canada, T6G 2P5
Reproductive efficiency is an important goal in the swine industry, and is represented by the number of pigs weaned per sow per year. Gilts represent a group in the breeding herd which deserves special attention, as they contribute disproportionately to overall unproductive days, leading to a reduction in breeding herd efficiency for the swine producers.
In gilts, a positive relationship exists between feed intake and ovulation rate, and gilts are therefore usually fed to appetite during the estrous cycle preceding mating ("flush feeding"). Conversely, it has been demonstrated that even short periods of feed restriction in the prepubertal gilt produce inhibitory effects on ovarian development. The effect of different patterns feeding on fertility are still unclear.
This experiment was conducted to demonstrate the interactions between different patterns of nutrition and reproduction in gilts. Twenty three pairs of littermate gilts were allocated to one of the three treatment groups as follows: HH- animals fed high plane of nutrition throughout the 21 D cycle(until breeding); HR- animals fed high plane from D1 to D7, restricted from D8 to D15, and fed high plane again from D16 until breeding; RH- animals restricted from D1 to D7 and then fed the high plane until breeding. The animals were slaughtered on D28 of pregnancy, the reproductive tract recovered and ovulation rate and embryonic survival recorded. Results are shown in Table 1.
Table 1. Effects of different planes of nutrition on gilt fertility.
| Treatment | Ovulation Rate 1 | # Embryos 1 | Embr. Surv.(%) 1 |
| HH | 17.2 + 0.64 | 14.5 + 1.0 | 84.8 + 4.7 a |
| HR | 18.4 + 0.70 | 12.8 + 1.1 | 68.7 + 5.0 b |
| RH | 17.7 + 0.67 | 15.0 + 1.1 | 83.3 + 4.9 a |
1 Mean + SEM
a,b Means with different superscripts within columns differ (P<0.05).
Implication: Regulating metabolic state of cyclic gilts through controlled feed intake can be used
to study effects on subsequent fertility. This will contribute to a better understanding of the
interactions between nutrition and reproduction, and to the nutritional management of breeding
sow herds.