Relationships between Carcass Quality and Temperament in Beef Cattle Rhonda C. Vann MAFES-Brown Loam Experiment Station- Raymond, MS

Introduction Economic implications associated with livestock temperament have not been fully determined (Grandin, 1994). Some producers do, in fact, consider temperament to be an important trait when selecting cattle for purchase (Elder et al., 1980). However, in many instances, genetic trait selection is often one-sided in the quest for a specific trait.

Introduction Within the cattle industry we have daily interactions with cattle which are influenced by the temperament of the animal. Many concerns can arise, which include animal handler safety, damage to equipment and facilities, injury of animal, etc. Several studies have reported reduced animal productivity related to temperaments (Voisinet et al., 1997).

Objectives The objectives of this study were to evaluate effects of exit velocity (EV, m/s), chute temperament score (CS) and pen temperament score (PS) and measure relationships between EV, CS and PS at two times near weaning with carcass traits and Warner-Bratzler Shear force (WBS) values in feedlot steers.

Chute Temperament Score 1 – calm – no movement 2 – restless, shifting 3 – squirming, occasional shaking of the squeeze chute or scale 4 – continuous vigorous movement and shaking of the device 5 – 4 plus rearing, twisting or violently struggling Voisinet et al., 1997

Pen Temperament Score 1 – nonagressive, docile, walks slowly, can approach slowly, not excited by humans or facilities. 2 – slightly aggressive, runs along fences, will stand in corner if humans stay away, may pace fence. 3 – moderately aggressive, runs along fences, head up and will run if humans come closer, stops before hitting gates and fences, avoids humans. 4 – aggressive, runs away, stays in back of group, head high and very aware of humans, may run into fences and gates even with some distance, will likely run into fences if alone in pen. 5 – very aggressive, excited runs into fences, runs over humans and anything else in path, “crazy”.

Experimental Procedures Angus crossbred calves (n=58) were assigned a pen score, then calves were weighed on a platform scale and assigned a chute score. Calves were then released into a hydraulic squeeze chute and restrained. While in the squeeze chute a blood sample was collected from tail vessel and then serum harvested for analysis of circulating cortisol concentrations.

Experimental Procedures Exit velocity from the squeeze chute was measured by a laser timing device (FarmTek) over approximately 1.83 m from the chute (m/s). Measurement one (T1) occurred 21 d after weaning and the second measurement (T2) 90 d later. Least square means were obtained from PROC MIXED procedure with a model which included breed of sire and age of dam for all variables. The model for carcass and feedlot traits also included harvest date.

Mean Exit Velocity for Pen Scores Pen Score T1LS MeanStd. Error 1 (n=3)2.20 xy (n=30)1.71 y (n=16)2.27 x (n=5)2.00 xy (n=4)2.75 x 0.42 xy Column means with different superscripts differ P < 0.05.

Mean Exit Velocity for Pen Scores Pen Score T2LS MeanStd. Error 1 (n=6) (n=28) (n=17) (n=6) (n=0) P < 0.001

Mean Exit Velocity for Chute Scores Chute Score T1LS MeanStd. Error 1 (n=10)2.63 x (n=27)1.94 y (n=19)1.92 y (n=2)2.26 xy (n=0) xy Column means with different superscripts differ P <

Mean Exit Velocity for Chute Scores Chute Score T2LS MeanStd. Error 1 (n=24) (n=26) (n=7) (n=0) 5 (n=0)

Influence of sire breed on measurements ItemAngus-SiredBrangus -Sired Weight T1 (kg) ± ± Weight T2 (kg) ± ± Feedlot End Weight (kg) ± ± Feedlot Gain (kg) ± ± WBS (kg)2.69 ± ± 0.28

Influence of sire breed on measurements ItemAngus-SiredBrangus -SiredP-value EV T1 (m/s)1.29 ± ± 0.36 EV T2 (m/s)1.80 ± ± 0.47 Intrasmuscular fat (%) 2.87 ± ± 0.12< 0.06 Carcass Rib fat (cm) 1.71 ± ± 0.25< 0.05 USDA Yield Grade 3.12 ± ± 0.32< 0.06

Warner-Bratzler Shear Force Values

Cortisol concentrations for chute and pen temperament scores

Results Breed of sire (AN or BN) was not a significant source of variation for EV, CS or PS, or carcass traits of longissimus muscle area (LMA); however, Brangus-sired steers had greater intramuscular fat (IMF; P < 0.06) at weaning and greater carcass LMA per hundred weight (P = 0.03) a higher USDA yield grade (P < 0.05).

Results The correlation coefficient (r) between EV and PS at T1 were 0.56 (P < 0.001) and at T2 were 0.61 (P < 0.001). The r between EV at T1 and WBS were 0.28 (P < 0.03) and EV at T2 and WBS were 0.34 (P < ). The r between EV and CS at T2 were 0.43 (P < 0.008).

Results The r between PS at T1 and WBS was 0.24 (P < 0.07) and at T2 was 0.35 (P < 0.08). The r between PS and cortisol at T1 was 0.28 (P < 0.04) and at T2 was 0.29 (P < 0.03).

Results The regression coefficients between EV and WBS at T1 was 0.37 kg (P < 0.04) and at T2 was 0.57 kg (P < ). The regression coefficients between PS and WBS at T1 was 0.39 kg (P < 0.07) and at T2 was 0.47 kg (P < 0.008).

Conclusions Breed of sire did not influence chute exit velocity, chute or pen temperament scores. Although the correlation coefficients between exit velocity and temperament scores were significantly different from zero the magnitudes were only moderate, however they were consistent across the various measures of temperament.

Conclusions As exit velocity and pen temperament scores increased WBS values also increased.

Three Year Data Compilation Angus crossbred steers (n=220) were assigned a PS, CS, and EV as described previously. Assessments of temperament were performed at weaning (PS, CS, EV 1) and again prior to departure to the feedlot (PS, CS, EV 2). Steers were harvested at the completion of the feedlot feeding period and carcass data collected as well as steaks collected for shear force after a 14 d aging period.

Three Year Data Compilation An overall temperament score, which comprised all measures of temperament, both subjective and objective were created {(EV+PS+CS)/3} and utilized in the statistical analysis. This compiled temperament score was divided into three categories: 1 = calm; 2 = intermediate; and 3 = temperamental (excitable).

Three Year Data Compilation Sire breeds consisted of Brangus, Angus and Hereford. Least square means were obtained from the Proc MIXED procedure of SAS with main effects of sire breed, individual sire, calf breed, and previous grazing regimen. Partial correlation coefficients were obtained using the Manova option of the Proc GLM procedure of SAS accounting for sire breed, individual sire, calf breed and previous grazing regimen.

Three Year Data Compilation Individual sire influenced (P < 0.04) pen (PS) and chute score (CS), exit velocity and cortisol concentrations at weaning, and PS (P < 0.02) and EV (P = 0.076) prior to departure to the feedlot, yield grade (P < 0.03), carcass marbling score and quality grade (P < 0.001).

Three Year Data Compilation Breed of sire influenced carcass weight, KPH (P < 0.08) and carcass rib fat and YG (P < 0.03). Breed of sire also influence PS at weaning and prior to departure to the feedlot (P < 0.03).

Three Year Data Compilation The correlation between weaning temperament and shear force values were 0.23 (P = 0.065); PS and CS prior to shipment to the feedlot and shear force values 0.22 (P = 0.069) and 0.23 (P = 0.062), respectively. As the compiled temperament score at weaning increased shear force values increased (P = 0.033).

Shear Force values for PS and CS at weaning and prior to departure to the feedlot

Shear Force values for compiled weaning temperament score

Three Year Data Compilation Pen scores at weaning were highly correlated with pen scores prior to shipment to the feedlot 0.45 (P = 0.002); exit velocity at weaning was correlated with exit velocity prior to shipment to the feedlot (P = ); CS at weaning were correlated with CS prior to shipment to the feedlot (P = 0.012).

Three Year Data Compilation Individual sires have direct effects on carcass quality as assessed by marbling score and quality grade and carcass yield grade. Measures of temperament whether subjective (pen and chute scores) or objective (exit velocity) are repeatable and moderately correlated at different management time points.

Conclusion Individual sire did influence all measurements of temperament and carcass quality and yield grade. These studies as well as other data (not reported here) indicate that disposition needs to be a consideration along with the other selection traits when making bull or mature cow or replacement heifer purchases which brings new animals into your cattle operation.

Conclusion This research is ongoing and in the near future we will be including investigations on the effects of temperament on immunity and health status of the animal as well as effects on reproductive efficiency in beef cattle. Our hope is that producers and the cattle industry utilize disposition in selection of animals which will be more productive in their respective environments (i.e. choose steers that will perform better in a feedlot situation and etc.).

Collaborators Dr. Ron Randel, TAMU-Overton Dr. Scott Willard, Mississippi State University Dr. Tom Welsh, TAMU-College Station Dr. Joe Paschal, TAMU-Corpus Christi Dr. Mike Brown, WTAMU Dr. Ty Lawrence, WTAMU Entire Crew at Brown Loam Experiment Station

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