Effects of Calf Birth Weight, Sex, and Number of Calvings on Assigned Maternal Disposition Scores
Little work has been conducted to compare maternal disposition scores assigned to a heifer/cow after calving, and if these scores remain stable over consecutive calvings. The objective of this trial was to determine if calf birth weight, sex, and the number of calvings affects the cows maternal disposition scores. The fall data set included observations from 406 calvings, which were pure Angus (n = 316), pure Simmental (n = 75), or crosses of the two breeds (n = 43). The spring data set included observations from 550 calvings, which were Angus (n = 253) or Simmental (n = 338). All calvings occurred on pasture. The data set included date and time of birth, birth weight (kg), sex of the calf, and a maternal disposition score. The maternal disposition score was based on the cow’s reaction to both the calf and human interaction. The scale used to score cows ranged from one through five and was created at the ISU beef farm. Data was analyzed using PROC GLIMMIX. There were no observed differences for disposition score in either season when cows birthed heavier calves (P > 0.86), if the cow had a bull versus a heifer (P > 0.50) or the number of calvings that they experienced (P > 0.76). In conclusion, using this particular maternal disposition scoring, no observed changes in disposition score occurred with calf birth weight, calf sex or the number of calvings.