Abstract #M38
Section: ADSA Production PhD Poster Competition (Graduate)
Session: ADSA Graduate Student (PhD) Production Poster Competition
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall B
Session: ADSA Graduate Student (PhD) Production Poster Competition
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall B
# M38
Relationship between ano-genital distance and fertility in Holstein cows.
M. Gobikrushanth*1, T. C. Bruinjé1, M. G. Colazo2, D. J. Ambrose1,2, 1Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, 2Livestock Research Section, Alberta Agriculture and Forestry, Edmonton, AB, Canada.
Key Words: ano-genital distance, height, fertility
Relationship between ano-genital distance and fertility in Holstein cows.
M. Gobikrushanth*1, T. C. Bruinjé1, M. G. Colazo2, D. J. Ambrose1,2, 1Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, 2Livestock Research Section, Alberta Agriculture and Forestry, Edmonton, AB, Canada.
The ano-genital distance (AGD) has been studied as a marker for genital development and fertility in rodents and primates. An inverse relationship between AGD (distance from anus to clitoris) and fertility in dairy cows was first reported in a preliminary study. Current objectives were to determine associations between (1) AGD and height at hip, and (2) categories of AGD and reproductive outcomes [pregnancy at 1st AI (P/AI), cumulative pregnancy at 120 DIM (P120), times bred, days open] in a larger population. AGD and height were measured in 573 cows (1st, 2nd and 3rd+ lactation [lac]; n = 203, 155 and 215) at 165 ± 4.3 DIM from 3 herds. The overall mean (±SEM) AGD and height were 132.3 ± 0.5mm (range, 96.0–170.0) and 149.6 ± 0.2cm (range, 138.0–161.0). Mean AGD and height, respectively, were shorter (P < 0.05) for 1st (125.8 ± 0.7mm and 149.2 ± 0.2cm) than 2nd (128.4 ± 0.7mm and 150.5 ± 0.2cm) and 3rd+ lac (128.6 ± 0.6mm and 150.6 ± 0.2cm). The overall correlation between AGD and height was very weak (r2 = 0.08; P < 0.01). The threshold AGD that predicted probability of P/AI (Receiver operating characteristic curve analysis) for 1st and 2nd lac cows were 126.0 (Sensitivity:61.9 and Specificity:66.4%), and 135.0 (Sensitivity:69.8 and Specificity:75.5%) mm, but AGD did not predict fertility in 3rd+ lac cows. Therefore, only 1st and 2nd lac cows were categorized into SHORT or LONG AGD (≤or > threshold for each lac). First lac cows of SHORT AGD (119.2 ± 0.7mm) group had greater (P < 0.05) P/AI (56.7 vs. 28.8%) and P120 (81.5 vs. 56.7%), fewer times bred (1.6 ± 0.1 vs. 2.5 ± 0.1) and days open (95.4 ± 5.9 vs. 125.7 ± 5.5d) than those in LONG AGD (136.2 ± 0.7mm). Similarly, 2nd lac SHORT AGD (125.6 ± 0.8mm) cows had greater (P < 0.05) P/AI (41.6 vs. 24.2%) and P120 (60.7 vs. 51.5%), fewer times bred (2.2 ± 0.2 vs. 2.6 ± 0.2) and days open (116.9 ± 6.3 vs. 147.7 ± 7.8 d) than LONG AGD (144.9 ± 1.0mm). Height did not differ between SHORT and LONG AGD cows in 1st and 2nd lac. In summary, AGD was very weakly associated with height, highly variable even among cows of similar lactation, and cows with shorter AGD were more fertile than those with longer AGD. The factors determining AGD in dairy cows remain to be explored.
Key Words: ano-genital distance, height, fertility
