Within the breeding herd the weaning-to-estrus interval (WEI) has a major effect on overall reproductive efficiency. It affects the non-productive days (NPD), the success of accurate heat detection and timing of insemination, subsequent litter size, the replacement rate in a farrowing group and the culling rate within the sow herd. Within current North American production systems, young growing sows in the first parities often pose the biggest challenge. First and second litter sows can be difficult to maintain within a farrowing group because of extended or variable WEI, poor rebreeding performance and\/or small subsequent litter sizes. Early weaning can worsen the situation. These problems are often attributed to loss of body condition, and thus body tissue reserves, due to the large metabolic demands of lactation on the young growing sow. There is ample evidence that changes in live weight and body composition can have profound effects on reproduction. However, there is also evidence that reproductive performance can be affected without obvious changes in body condition. Differences in nutrient partitioning between growing and mature sows, mediated through metabolic hormones, may impact on levels of reproductive hormones and consequent reproductive performance. In an effort to better understand the fundamental differences between growing and mature sows in control of post-weaning reproduction, comparisons of first and fifth litter sows from farrowing through early gestation were part of an intensive research study conducted at the University of Manitoba Glenlea Swine Research Unit. It has been proposed that modern genotype gilts are more likely to remain in the breeding herd if they begin their breeding life with greater body tissue reserves (i.e. are more mature), than is currently common practice. Our results along with our own research herd performance support this concept. While early-weaned 1st parity sows in the current study demonstrated variability in weaning-to-estrus interval (WEI) and subsequent reproductive performance, this is not a common problem in our herd. Reproduction and WEI following 18 to 21 day lactation are comparable to multi-parous sows. In conclusion, our data is consistent with the theory that variability in WEI and subsequent reproductive performance of early-weaned 1st parity sows is linked to body tissue reserves and catabolism during late gestation as well as throughout lactation. It also points to the need for ongoing research with modern genotypes to determine more appropriate feeding and management strategies to realize their reproductive potential and optimize longevity in the breeding herd.<\/p>\n","protected":false},"excerpt":{"rendered":"
Within the breeding herd the weaning-to-estrus interval (WEI) has a major effect on overall reproductive efficiency. It affects the non-productive days (NPD), the success of accurate heat detection and timing of insemination, subsequent litter size, the replacement rate in a farrowing group and the culling rate within the sow herd. Within current North American production […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[930],"tags":[4658,8882,26599,10033,2471,2349,2344,4564,1972,2472,23351,11492,2800,527,4659,25161,5886,103,6904,46,108,102,20007,105,3322,14804,269,129,5620,61,818,1318,6559,1978,48,10859,8921,63,16262,17743,27282,18599,4660,14980,1533,104,96,35,17291,20911,4874,6053,2446,3790,77,4661,1301],"class_list":["post-4146","post","type-post","status-publish","format-standard","hentry","category-production","tag-wei","tag-al","tag-anxious-sow-farrowing","tag-arc","tag-body-condition","tag-breed","tag-breeding","tag-comparison","tag-condition","tag-culling","tag-daytime-farrowing-swine","tag-definefarrowing-group","tag-early-weaning","tag-efficiency","tag-embryo","tag-eucalyptus-oil-swine-feed","tag-farrow","tag-farrowing","tag-fee","tag-feed","tag-feeding","tag-gestation","tag-gh","tag-gilt","tag-gilts","tag-hal","tag-heat","tag-hormones","tag-insemination","tag-lactation","tag-litter","tag-litter-size","tag-longevity","tag-loss","tag-management","tag-nat","tag-npd","tag-performance","tag-pl","tag-prod","tag-production","tag-replacement","tag-reproductive-efficiency","tag-search","tag-size","tag-sow","tag-sows","tag-swine","tag-swine-research","tag-t","tag-tan","tag-use","tag-variability","tag-weaned","tag-weaning","tag-weaning-to-estrus-interval","tag-weight"],"_links":{"self":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/4146","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/comments?post=4146"}],"version-history":[{"count":0,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/4146\/revisions"}],"wp:attachment":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/media?parent=4146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/categories?post=4146"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/tags?post=4146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}