有道理 好好把握，好東西多交流總結作者: 珍愛 時間: 2010-6-5 22:24
擴群就用性控作者: apple12151007 時間: 2010-6-7 11:49
奶牛性控精液受胎率要低一些:wulai:作者: 嗷嗷叫的牛 時間: 2010-6-9 21:30
跟蹤配種效果能好些。作者: 李良彬 時間: 2010-6-10 19:18
選擇優秀的性控凍精在擴群時和優秀核心群的建立時使用是有必要的。受胎率可能會略低于常規凍精。作者: dbnts 時間: 2010-6-13 21:52
剛好有篇關于性控精液的文章，感興趣可以下載看一看Sex-sorted semen for dairy heifers: Effects on reproductive and lactational performances
The objectives of this study were to evaluate the effects of using sex-sorted semen for first AI of heifers on health and productivity during first lactation. Holstein heifers (herd A=227 and herd B=1,144) received first artificial insemination (AI) with sex-sorted semen (SX; n=343) or conventional semen (CS; n=1,028), and all heifers that displayed estrus after first AI were reinseminated with conventional semen up to 11 times before being culled. Age at first AI was 13.1±0.1 and 13.8±0.1 mo for SX and CS heifers, respectively, in herd A and 12.9±0.1 mo for both SX and CS heifers in herd B. Pregnancy per AI after first AI was greater for CS heifers than for SX heifers (51.8 vs. 40.2%). From heifers initially enrolled, 70.2% calved in herds A (n=188) or B (n=774) and first-lactation data were collected. Interval from first AI to calving was greater for SX heifers than for CS heifers (10.2±0.1 vs. 9.9±0.1 mo). Among heifers conceiving to first AI, SX heifers were more likely than CS heifers to deliver a female calf (85.7 vs. 47.7%), but because SX heifers were more likely to deliver a dead calf (8.8 vs. 3.4%), the difference in proportion of SX and CS heifers delivering a live female calf was smaller than expected (SX=79.1%; CS=47.2%). Rearing cost from first AI to calving was greater for SX heifers than for CS heifers ($775.3±6.7 vs. $750.0±5.9), but calf revenue tended to be greater for SX heifers ($142.0±7.2 vs. $126.7±6.4) and cost per female calf produced was smaller for SX heifers than for CS heifers ($−809.4±10.8 vs. $−1,249.7±10.9). Treatment did not affect calving difficulty, proportion of heifers needing assistance, and incidence of retained fetal membranes or metritis. Among heifers that conceived to first AI, however, SX heifers were more likely to be culled within 30 DIM (3.3 vs. 1.6%) and tended to be more likely to be culled within 60 DIM (5.5 vs. 3.4%) than CS heifers, but overall replacement cost was not different ($136.8±13.4). Total milk yield (9,245.5±84.7kg) and income over feed cost ($554.7±5.1) were not different. Overall economic return was greater for SX heifers than CS heifers ($−83.7±36.7 vs. −175.3±33.4). Use of sex-sorted semen for first insemination of virgin heifers reduced the cost per female calf produced and increased the economic return during the first lactation. http://www.journalofdairyscience.org/article/S0022-0302(10)00252-3/abstract