Phenotypic relationships between docility and reproduction in Angus heifers

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Show simple item record White, K. L. Bormann, Jennifer M. Olson, KC Jaeger, John Johnson, Sandra Downey, B. Grieger, David M. Waggoner, J. W. Moser, D. W. Weaber, Robert L. 2016-09-20T17:40:44Z 2016-09-20T17:40:44Z
dc.description Citation: White, K. L., Bormann, J. M., Olson, K. C., Jaeger, J. R., Johnson, S., Downey, B., . . . Weaber, R. L. (2016). Phenotypic relationships between docility and reproduction in Angus heifers. Journal of Animal Science, 94(2), 483-489. doi:10.2527/jas2015-9327
dc.description.abstract The objective of this study was to elucidate the phenotypic relationships between docility and first-service AI conception rate in heifers. Data (n = 337) collected from 3 cooperator herds in Kansas at the start of synchronization protocol included exit velocity (EV), chute score (CS), fecal cortisol (FC), and blood serum cortisol (BC). Data were analyzed using logistic regression with 30-d pregnancy rate as the dependent variable. The model included the fixed effect of contemporary group and the covariates FC, BC, EV, CS, BW, and age. Correlation coefficients were calculated between all continuous traits. Pregnancy rate ranged from 34% to 60% between herds. Blood cortisol positively correlated with EV (r = 0.22, P < 0.01), negatively correlated with age (r = -0.12, P < 0.03), and tended to be negatively correlated with BW (r = -0.10, P = 0.09). Exit velocity was positively correlated with CS (r = 0.24, P < 0.01) and negatively correlated with BW (r = -0.15, P < 0.01) and age (r = -0.12, P < 0.03). Chute score negatively correlated with age (r = -0.14, P < 0.01), and age and BW were moderately positively correlated (r = 0.42, P < 0.01), as expected. Older, heavier animals generally had better temperament, as indicated by lower BC, EV, and CS. The power of our test could detect no significant predictors of 30-d pregnancy for the combined data from all ranches. When the data were divided by ranch, CS (P < 0.03) and BW (P < 0.01) were both significant predictors for 30-d pregnancy for ranch 1. The odds ratio estimate for CS has an inverse relationship with pregnancy, meaning that a 1-unit increase in average CS will reduce the probability of pregnancy at ranch 1 by 48.1%. Weight also has a negative impact on pregnancy because a 1-kg increase in BW will decrease the probability of pregnancy by 2.2%. Fertility is a complex trait that depends on many factors; our data suggest that docility is 1 factor that warrants further investigation.
dc.rights Copyright © 2016. American Society of Animal Science.
dc.subject Beef Cattle
dc.subject Docility
dc.subject Fertility
dc.subject Genetics
dc.subject Pregnancy
dc.subject Cortisol
dc.title Phenotypic relationships between docility and reproduction in Angus heifers
dc.type Article 2016
dc.citation.doi 10.2527/jas2015-9327
dc.citation.epage 489
dc.citation.issn 0021-8812
dc.citation.issue 2
dc.citation.jtitle Journal of Animal Science
dc.citation.spage 483
dc.citation.volume 94
dc.description.embargo 2017-01
dc.contributor.authoreid jbormann
dc.contributor.authoreid kcolson
dc.contributor.authoreid jrjaeger
dc.contributor.authoreid sandyj
dc.contributor.authoreid dgrieger
dc.contributor.authoreid bweaber

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