scholarly journals Genetic merit for fertility traits in Holstein cows: II. Ovarian follicular and corpus luteum dynamics, reproductive hormones, and estrus behavior

2012 ◽  
Vol 95 (7) ◽  
pp. 3698-3710 ◽  
Author(s):  
S.B. Cummins ◽  
P. Lonergan ◽  
A.C.O. Evans ◽  
S.T. Butler
2019 ◽  
Vol 102 (5) ◽  
pp. 4651-4661 ◽  
Author(s):  
S.G. Moore ◽  
S.B. Cummins ◽  
S. Mamo ◽  
P. Lonergan ◽  
T. Fair ◽  
...  

2012 ◽  
Vol 95 (3) ◽  
pp. 1310-1322 ◽  
Author(s):  
S.B. Cummins ◽  
P. Lonergan ◽  
A.C.O. Evans ◽  
D.P. Berry ◽  
R.D. Evans ◽  
...  

2014 ◽  
Vol 97 (9) ◽  
pp. 5543-5557 ◽  
Author(s):  
S.G. Moore ◽  
S. Scully ◽  
J.A. Browne ◽  
T. Fair ◽  
S.T. Butler

2012 ◽  
Vol 57 (No. 3) ◽  
pp. 108-114 ◽  
Author(s):  
V. Zink ◽  
J. Lassen ◽  
M. Štípková

The aim of this study was to estimate genetic parameters for female fertility and production traits in first-parity Czech Holstein cows and to quantify the effect of using this information on the accuracy of a selection index in seven different scenarios. In order to estimate genetic (co)variance components, the DMU software running an AI-REML algorithm was used. The analyses were made using a series of bivariate animal models. The pedigree included 164 125 animals and it was set up using a pruned animal model design. The present study included the following female fertility traits for the first lactations: calving to the first insemination (CF), days open (DO), calving from the first to the last insemination (FL), and milk production traits: milk production (MLK), kg of fat (FAT), and kg of protein (PROT). The heritability for all the investigated fertility traits was low and close to 0. Moderate heritabilities for production traits ranging from 0.20 (MLK) to 0.23 (PROT) were estimated. The strongest unfavourable correlation was found between PROT and DO (0.49). Other estimated correlations between fertility traits and production traits were moderate, ranging from 0.26 to 0.41. The results of this study evidence that cows with the poorest genetic potential for reproductive performance are those having high genetic potential for milk production and milk components. The results also show that the number of days from calving to new pregnancy depends on the production level. Seven investigated scenarios using selection index theory show a clear trend for increasing accuracy when more fertility traits were added as well as when higher numbers of daughters with information on reproduction traits per sire were available.  


2018 ◽  
Vol 50 (8) ◽  
pp. 1913-1920 ◽  
Author(s):  
Jose C. Leyva-Corona ◽  
Javier R. Reyna-Granados ◽  
Ricardo Zamorano-Algandar ◽  
Miguel A. Sanchez-Castro ◽  
Milton G. Thomas ◽  
...  

2020 ◽  
Vol 32 (2) ◽  
pp. 130
Author(s):  
M. Oliveira ◽  
R. Santos ◽  
R. Chebel ◽  
D. Demetrio

Excessive heat affects the fertility of high production lactating cows, and reduced pregnancy rates (PR) are observed during summer and early fall. Embryo production programs are used to produce more calves from high genetic merit animals, but could it also increase fertility by bypassing all the negative variables affecting the embryo development before Day 7 (oocyte development, ovulation, fertilization, early embryo development)? The data from AIs and embryo transfers (ET) between June 2017 and May 2019 were analysed. June, July, August, September, and October were called critical months (first-service AI conception rate dropped below 44%). The cows were located at Maddox Dairy in Riverdale, CA, USA, a Holstein herd that milks 3500 cows with a 305-day mature-equivalent milk production of 12 800 kg. First- and second-lactation cows were enrolled in a Presynch-Ovsynch oestrus-synchronization program and scheduled for the first AI at 86 days after calving or to receive an embryo 7 or 8 days after the expected heat. The embryos were produced invivo or invitro from Holstein donors and were transferred fresh or frozen. Blood was sampled on Day 30 after expected heat day (23 days after embryo transfer), and pregnancy was detected by the IDEXX PAG Bovine Pregnancy Test. Table 1 summarises the results, where ET PR% is the number of pregnant cows divided by the number of cows that received and embryo. All the cows synchronized for AI were bred, but only cows with the presence of a corpus luteum (CL) on ET day received an embryo. The presence of a CL was not detected in 28.7% (471/1642) of the cows (32.2% in the critical months and 25.7% in the others). Unfortunately, we could not detect the presence of a CL by ultrasonography every time we transferred embryos, so the nonovulation rate might be overestimated. The cows without a CL were considered open and used to calculate the adjusted PR (AdjPR%). Embryo transfer PR is superior to that of AI, especially during the critical months. Fresh invivo embryos have the most impact. When the cows without CLs are considered open, the difference between AI and ET is still evident for fresh invivo embryos. Besides producing animals with higher genetic merit, depending on the type of embryo used, ET can increase fertility in lactating Holstein cows, especially during the critical months. The other benefit of using ET is that cows that do not ovulate are synchronized right away, which is not the case for AI cows. Table 1.AI×embryo transfer in lactating Holstein cows1 from June 2017 to May 20192 Item Critical months (June to October) Other months (November to May) All year %PR n Adj PR% n %PR n Adj PR% n %PR n Adj PR% n Artificial insemination 41.2% 896 41.2% 896 47.7% 1767 47.7% 1767 45.5% 2663 2663 Fresh invivo embryo 62.7% 373 47.5% 493 69.5% 262 55.3% 329 65.5% 635 50.6% 822 Frozen invivo embryo 59.3% 221 44.8% 292 59.4% 256 47.3% 322 59.3% 477 46.1% 614 IVF fresh embryo 47.9% 167 36.2% 221 54.0% 363 43.0% 456 52.1% 530 40.8% 677 Total embryos 58.5% 761 44.2% 1006 60.2% 881 47.9% 1107 59.4% 1642 46.1% 2113 1Lactating Holstein cows, first and second lactation, first service, Presynch-Ovsynch, 85 DIM. 2PR%=the number of pregnant cows divided by the number of cows that received and embryo; AdjPR%=adjusted pregnancy rate.


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