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Sow performance in response to natural betaine fed during lactation and weaning-to-35 d post-insemination during non-summer months
This study was conducted to evaluate the effect of feeding natural betaine during lactation and weaning-to-35 d post-insemination on subsequent sow reproduction during non-summer months. This study is a counterpart to the experiment conducted during the summer, in which feeding 0.20% betaine during lactation decreased wean-to-estrus interval and increased subsequent litter size. A total of 627 sows were allocated by parity (300 parity 1 and 2 sows (young) and 327 parity 3 to 6 sows (mature)) to a 2 x 2 factorial arrangement of treatments. Factors included betaine supplementation: 1) in lactation (0 or 0.2%) and 2) from weaning through early gestation (0 or 0.2%). Lactation diets were corn-soybean meal based with 10% rice bran, 6.0% wheat middlings, and contained 651 ppm of choline, 3.31 g SID Lys/Mcal ME and a SID Met+Cys:Lys ratio of 0.56. Gestation diets were corn-soybean meal based with 30% wheat middlings, 15% rice bran, and contained 651 ppm choline, 1.82 g SID Lys/Mcal ME and a SID Met+Cys:Lys ratio of 0.69. Data were analyzed using the MIXED procedure of SAS and GLM was used for dichotomous variables. Average temperature was 22.9±1°C during lactation and 23.7±0.6°C during the weaning-to-35 d post-insemination period. Betaine fed in lactation did not affect ADFI (P=0.155; 4.85 vs. 4.96 kg/d), sow ADG (P=0.939; -0.102 vs. -0.098, kg/d), litter gain (P=0.687; 47.19 vs. 47.74, kg), and number of pigs weaned (P=0.622; 10.74 vs. 1078) compared to the control. Supplementation of betaine during lactation to young, but not mature, sows reduced the percentage of no-value (<3.62 kg BW) pigs (interaction, P=0.036; 10% vs 25%). Feeding betaine after weaning to young sows reduced the percentage of sows returning to estrus (P=0.002; 91.94 vs. 98.00%), but did not affect mature sows (P=0.51; 98.15 vs. 99.40%). Post hoc analysis showed that wean-to-estrus interval was reduced (P=0.022) for parity 2 and 3 sows fed betaine after weaning (6.15 vs. 8.41 d). Supplementation of betaine during lactation reduced farrowing rate in mature sows (P=0.001; 78.06 vs. 91.43) but not young sows (P=0.60; 82.69 vs. 80.63%). The reduction in farrowing rate was driven by a greater cull percentage for reproductive reasons (P=0.005; 14.03 vs. 4.3%). Feeding betaine post-weaning reduced total pigs born (P=0.017; 12.79 vs 13.54). Results suggest that the use of 0.2% betaine during lactation and post-weaning did not benefit sow performance and subsequent litter size, as was the case for summer-bred sows in the previous study.
Keywords: betaine, sows, lactation.