Ingenhoff L, Hall E, Ranjbar Ni S, House J K
Livestock Veterinary Teaching and Research Unit, Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, New South Wales 2570, Australia.
Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia.
Aust Vet J. 2017 Apr;95(4):110-117. doi: 10.1111/avj.12573.
To determine the effects of ovarian structures present at Ovsynch™ enrolment, disease history, lactation variables and times bred on pregnancy per fixed-time artificial insemination (FTAI) following fixed-time insemination after Ovsynch and to determine the relationship between the size of ovarian follicular structures and concurrent presence of a corpus luteum (CL).
The study was conducted in a 3000-cow Holstein dairy herd. Over a 6-month period, 886 non-pregnant cows were examined by transrectal ultrasound and enrolled into 1132 Ovsynch events. Enrolled cows were synchronised using an Ovsynch-56 protocol. At enrolment, both ovaries were scanned by transrectal ultrasound to identify and record the presence and size of ovarian structures. Cows that did not return to oestrus were pregnancy tested 32-38 days post-insemination. Univariable and multivariable generalised linear mixed models (GLMMs) were used to determine the effect of each variable on pregnancy per FTAI. A univariable GLMM was also used to analyse the relationship between size of the dominant follicular structure and concurrent presence of a CL.
CL size (P = 0.039) and presence of a luteal cyst (P = 0.002) at Ovsynch enrolment significantly increased the odds of pregnancy. Occurrence of lameness (P = 0.035) or mastitis (P = 0.008) between calving and enrolment significantly decreased the odds of pregnancy. Neither the presence nor size of a follicular structure significantly affected the odds of pregnancy, although cows with larger follicular structures were less likely to have a concurrent CL (P < 0.001).
Presence of luteal tissue at Ovsynch enrolment and recent disease events affected pregnancy per FTAI in cows inseminated after Ovsynch.
确定在Ovsynch™程序开始时存在的卵巢结构、疾病史、泌乳变量以及配种次数对Ovsynch程序后定时人工授精（FTAI）的妊娠率的影响，并确定卵巢卵泡结构大小与黄体（CL）同时存在之间的关系。
该研究在一个拥有3000头奶牛的荷斯坦奶牛群中进行。在6个月的时间里，通过经直肠超声对886头未怀孕的奶牛进行检查，并将其纳入1132次Ovsynch程序。纳入的奶牛使用Ovsynch - 56方案进行同期发情处理。在程序开始时，通过经直肠超声对两侧卵巢进行扫描，以识别并记录卵巢结构的存在情况和大小。未发情的奶牛在授精后32 - 38天进行妊娠检测。使用单变量和多变量广义线性混合模型（GLMMs）来确定每个变量对每次FTAI妊娠率的影响。还使用单变量GLMM来分析优势卵泡结构大小与CL同时存在之间的关系。
在Ovsynch程序开始时，CL大小（P = 0.039）和黄体囊肿的存在（P = 0.002）显著增加了妊娠几率。产犊至程序开始期间出现跛行（P = 0.035）或乳腺炎（P = 0.008）显著降低了妊娠几率。卵泡结构的存在与否及大小均未对妊娠几率产生显著影响，尽管卵泡结构较大的奶牛同时存在CL的可能性较小（P < 0.001）。
在Ovsynch程序开始时黄体组织的存在以及近期的疾病事件影响了Ovsynch程序后授精奶牛的每次FTAI妊娠率。
