Recent work at the University of Alberta has shown that the performance of contemporary dam-line first parity sows is truly amazing! Even when primiparous sows are induced to lose large amounts of body tissues through imposed feed restriction during peak lactation, there is a relative lack of effect on many measures of post-weaning fertility. However, a second parity \u201cdip\u201d or lack of an increase in second litter size, is often observed in production. First and second parity sows subjected to \u201cskip-a-heat\u201d breeding (bred at the 2nd estrus after weaning, or \u201cskipped\u201d) exhibited an increase of two pigs born compared to sows bred at first post-weaning estrus but this increase in litter size also resulted in an accumulation of 21 non-productive days (NPD) and a 9% chance of sows not standing to be bred at 2nd estrus. Recent data on the changing reproductive characteristics of contemporary commercial sows suggested that the response to skip-a-heat breeding in first parity sow needs to be re-evaluated. This trial re-assessed the effect of breeding sows at 1st vs. 2nd post-weaning estrus on follicular development, size of the largest ovulatory follicle, ovulation rate and embryonic survival to day 30 in contemporary commercial sows. Results confirmed that under good management practices, high production performance is achievable: 95% of sows returned to estrus within 10 days; 98% of sows bred; 100% of sows \u201cskipped\u201d sows detected in heat; and a 92% conception rate. However, litter size at d 30 appeared to be limited because of lower embryonic survival in sows bred at first post-weaning estrus. The present study also confirmed that breeding first parity weaned sows at 2nd post-weaning estrus will negate the effects of the \u201csecond parity dip.\u201d Alternative methods to increase second parity litter size without the accumulation of the 22 NPD associated with \u201cskip-a-heat\u201d merits further investigation.<\/p>\n","protected":false},"excerpt":{"rendered":"
Recent work at the University of Alberta has shown that the performance of contemporary dam-line first parity sows is truly amazing! Even when primiparous sows are induced to lose large amounts of body tissues through imposed feed restriction during peak lactation, there is a relative lack of effect on many measures of post-weaning fertility. However, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[928],"tags":[8882,1784,2096,13816,19216,12251,2349,2344,516,4659,3356,103,6904,46,20007,269,61,818,1318,9633,48,10859,8921,5671,3465,15459,63,14,8927,33,1319,17743,27282,1533,8764,104,96,161,20911,4874,26223,6053,3790,77,2481],"class_list":["post-5573","post","type-post","status-publish","format-standard","hentry","category-welfare","tag-al","tag-alberta","tag-alternative","tag-ass","tag-assess","tag-born","tag-breed","tag-breeding","tag-breeding-sows","tag-embryo","tag-estrus","tag-farrowing","tag-fee","tag-feed","tag-gh","tag-heat","tag-lactation","tag-litter","tag-litter-size","tag-littersize-first-parity-sow","tag-management","tag-nat","tag-npd","tag-parity","tag-pea","tag-ped","tag-performance","tag-pig","tag-pig-wean","tag-pigs","tag-pregnancy","tag-prod","tag-production","tag-size","tag-skip-a-heat","tag-sow","tag-sows","tag-survival","tag-t","tag-tan","tag-the-effects","tag-use","tag-weaned","tag-weaning","tag-work"],"_links":{"self":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/5573","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=5573"}],"version-history":[{"count":0,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/5573\/revisions"}],"wp:attachment":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/media?parent=5573"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/categories?post=5573"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/tags?post=5573"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}