Postpartum Maternal Behavior Score in Six Breed Groups of Beef Cattle over Twenty-Five Years

The objective of this study was to determine the effects of fixed sources of variation on postpartum maternal behavior score (MBS) in six breed groups of beef cows. Postpartum MBS were determined on 5070 births representing the progeny of 142 sires and 145 maternal grandsires used in purebred herds of the University of Arkansas Agricultural Experiment Station over a 25-yr period. Breed groups included Angus (n = 2073), Charolais (n = 549), Hereford (n = 722), Heritage Angus (n = 445), Polled Hereford (n = 981), and Red Poll (n = 300). Within 24 h of birth, a MBS was assigned as the handler obtained calf birth BW and body condition of each calf. Postpartum MBS were 1) very aggressive, 2) very attentive, 3) indifferent, and 4) apathetic. Variation in MBS across breeds was partitioned using a repeated measures model that included terms for an overall mean, year, breed, within breed, age of dam, sex of calf, body condition of calf, sire of calf, and maternal grandsire of calf. Across breed, important sources of variation (P<0.01) in MBS were year, age of dam, body condition of calf at birth, breed, sire within breed, and sire of dam within breed. Dams giving birth to calves in thin body condition had greater (P<0.01) mean MBS than dams giving birth to calves in average or fat body condition (2.34 vs 2.24 vs 2.19), respectively. These results suggest MBS is influenced by several sources of variation, which should be considered when evaluating maternal behavior in selection programs.