Chute Score Research Articles

13 Effects of an acclimation protocol during the handling events of the 7 d CO-synch + CIDR protocol on temperament and reproductive performance of Bos taurus commercial beef heifers

Abstract It has been previously reported that cattle temperament significantly impacts fertility to estrous synchronization (ES) protocols. In addition, enrolling heifers to acclimation protocols following weaning resulted in improved reproductive parameters with an increased proportion of acclimated heifers reaching puberty earlier when compared with non-acclimated cohorts. The objective of the present experiment was to assess the effects of an acclimation protocol during the handling events of an ES on changes in temperament and fertility to the ES protocol in Bos taurus commercial beef heifers. A total of 361 Angus-influenced commercial heifers from 5 different locations were enrolled in the experiment. Before enrolling heifers in the 7-d CO-Synch + CIDR protocol (d -10), individual heifers were evaluated for reproductive tract score (RTS), and chute score (CS) and stratified to receive acclimation (TRT) or to serve as control (CTRL). On d -10, heifers from TRT and CTRL groups received ear tags of different colors and individuals from CTRL and TRT were kept together in their pastures. Before each handling event of the ES (d 0,7,10), TRT heifers were sorted from CTRL and submitted to acclimation, which consisted of running heifers through the handling facilities without catching individuals in the restraining chute. Treatment heifers were then comingled with CTRL heifers, and all heifers were brought to the handling facilities for the ES event. Individual CS and exit velocities (EV) were recorded for all animals at all days (-10,0,7,10). Chute scores were recorded in a 1 to 5 scale, where 1 = calm, no movement; 2 = restless movements; 3 = frequent movement, vocalization; 4 = constant moving, vocalization, shaking of the chute; 5 = violent, continuous struggling. Individual estrus detection patch scores were assessed at the day of fixed-time artificial insemination (FTAI) based on percentage of activation, where 0 = lost; 1 = less than 25% activated, 2 = less than 50% activated, 3 = less than 75% activated, 4 = more than 75% activated. Pregnancy status was determined by rectal ultrasonography approximately 40 d after FTAI. Estrus detection patch scores did not differ between CTRL and TRT heifers (P = 0.1906). In addition, pregnancy rates to FTAI did not differ between TRT and CTRL heifers (56.81% and 52.74%; P = 0.3563). Reproductive tract scores (P = 0.777), EV (P = 0.9607) and CS (P = 0.990) did not differ between CTRL and TRT on d -10. However, CS, but not EV was decreased on d 7 (P = 0.001) and 10 (P = 0.0002) for TRT heifers when compared with CTRL. We conclude that enrolling heifers to an acclimation protocol during the handling events of the ES protocol was effective at decreasing excitability of heifers by the day of FTAI, as evidenced by decreased CS observed for TRT heifers on d 7, and 10 but did not support an increase in fertility to the ES protocol.

101 Effects of moderate exercise regimen on reproductive development of replacement beef heifers reared in drylots at a high stocking density

Abstract This experiment evaluated growth and reproductive development of beef heifers reared at a high stocking density and provided with access to an exercise area. The experiment was replicated over 2 yr, with a total of 180 Angus × Brahman heifers. Each year, 90 heifers were ranked by age (264 ± 1 d) and body weight (BW; 200 ± 2 kg) on d 0, and assigned to a) 1 of 6 drylot pens (10 × 14 m pens; 10 heifers/pen) resulting in a stocking density of 14 m2/heifer (DENS), or b) 1 of 3 paddocks (2-ha paddocks; 10 heifers/paddock) resulting in a stocking density of 2,000 m2/heifer (CON). On d 15, 3 DENS pens were randomly selected and given access to an exercise area (DENS-EX) for 1 h three times weekly. Negligible forage was available for CON heifers, whereas all heifers received the same limit fed diet which averaged 13 kg/heifer daily of a corn-based diet. Heifer shrunk BW was recorded after 16 h of feed and water withdrawal on d -3 and 225 for BW gain calculation. Heifer temperament (chute score, exit velocity, and temperament score) were evaluated on d 0 and 225. Heifers were also fitted on d 0 with a pedometer behind their shoulder and an ear tag (CowManager, Select Sires, Plain City, OH) to record behavioral responses. Each week, pedometer results were recorded, and blood samples were collected for puberty evaluation via plasma progesterone. Heifers from CON had more (P < 0.05) steps per week compared with DENS and DENS-EX (23,973, 6,706, and 12,354 steps/week, respectively; SEM = 1,247), and DENS-EX heifers had more (P < 0.05) steps per week compared with DENS. Heifers from CON spent more (P < 0.05) time ruminating and eating compared with DENS and DENS-EX. No treatment effects (P ≥ 0.91) were detected for heifer BW gain (0.820, 0.815, and 0.824 kg/d for CON, DENS, and DENS-EX, respectively; SEM = 0.016). Heifers from DENS had greater (P ≤ 0.05) exit velocity and temperament score on d 225 compared with DENS-EX and CON. Heifers from DENS experienced delayed puberty attainment (treatment x day; P < 0.01) compared with DENS-EX and CON. A greater (P ≤ 0.05) proportion of CON heifers were pubertal by day 105 compared with DENS and DENS-EX (30.0, 11.6, and 15.0%, respectively; SEM = 6.5), whereas a greater (P < 0.05) proportion of CON and DENS-EX heifers were pubertal by d 154 compared with DENS (61.7, 66.7, and 43.3%, respectively; SEM = 6.5). Results from this experiment demonstrate that providing heifers with an exercise area alleviated the negative effects associated with high stocking density on their reproductive development. This work is supported by the USDA-NIFA AFRI program (#2021-67015-34083).

130 Effect of an appeasing substance application on growth, stress, handling quality and reproduction of Bos indicus beef heifers synchronized to fixed-time AI

Abstract This experiment evaluated the effects of an analogue of bovine appeasing substance (BAS) on growth, stress, handling quality, and reproduction of Nellore heifers. Twenty-nine heifers [body condition score (BCS) = 4.84 ± 0.13; body weight (BW) = 371 ± 0.77 kg; 23 ± 2 months of age)] were assigned to 1 of 2 treatments: 1) Saline solution (0.9 NaCl; n = 14) or BAS (Secure Cattle, IRSEA Group, Quartier Salignan, France; n = 15). Both solutions were applied topically in the nuchal skin area (5 mL/heifers) at the beginning (d -9) of the fixed-time artificial insemination protocol (FTAI). Heifers were allocated in two different pastures according to the treatment (one pasture per treatment) for 15 d (time of action of BAS) and then combined in a single group (both treatments in the same pasture). Heifers were inseminated on d 0, and BW and BCS were collected on d -9 and 40. The temperament in the squeeze chute (entry and exit scores; scale 1 – 3; chute score; scale 1 – 5; greater values mean more reactive heifers) and blood samples were collected on d -9, 0, 7, 14 and 30. The percentual of aggression, accident, and dirtiness in the perineal region were evaluated on d 0 along with time to inseminate, estrus expression scores (scale 1 – 3; 1 = no expression, 2 = low expression, 3 = greater expression), and dominant follicle size. The corpus luteum size was measured on d 7 and 14, and the pregnancy and embryo size on d 40. The BAS vs. Saline-treated heifers tended to have greater BW change (23.6 vs. 20.8 ± 1.03 kg; P = 0.09) and had greater BCS change (0.05 vs. -0.21 ± 0.05; P < 0.01). The BAS vs. Saline-treated heifers tended to have lesser entry scores (1.42 vs. 1.67 ± 0.09; P = 0.09) and percentual of dirtiness in the perineal region (48.3 vs. 71.1 ± 8.67 %; P = 0.06), and no effects of treatment were detected (P ≥ 0.39) for chute score, exit score, aggression, accident and time to inseminate. The BAS vs. Saline-treated heifers had greater estrus scores (2.00 vs. 1.27 ± 0.21; P = 0.03), and no effects were detected (P ≥ 0.11) for ovarian variables, pregnancy rate, and conceptus size. Furthermore, no treatment effects were detected (P ≥ 0.25) for serum concentration of cortisol and plasma concentration of haptoglobin, ceruloplasmin, and progesterone. Therefore, BAS application at the beginning of the FTAI protocol could decrease the temperament and dirtiness in the perineal region and increase the growth and estrus expression of beef heifers.

PSIII-19 Effect of Hemp (Cannabis sativa) Supplementation on Vital and Behavioral Responses of Weaned Beef Cattle

Abstract Weaning induces stress to both cows and calves and hence, reduces growth performance and behavioral characteristics. The objective of this study is to evaluate the effect of industrial hemp supplementation on the vital and behavioral parameters on calves. Twelve (12) apparently healthy calves, with average body weight of 600 lb and ages 6 months were used for this study. These calves were randomly divided into four (4) groups of three calves per group and hemp was supplemented. Group 1 (20/200 mg normal concentrate for 4 weeks, CC), group 2 (14 days feeding normal concentrate pre-weaning and 14 days of feeding 20/200 mg industrial hemp CH), group 3 (14 days of industrial hemp supplementation pre-weaning and 14 days of normal concentrate HC) and group 4 (4 weeks of hemp supplemented feed). Vital and behavioral vparameters were measured once per week, for two weeks pre-weaning and two weeks post-weaning. Temperature was measured using thermometer, pulse rate was measured using stethoscope and respiratory rate by costo-abdominal movement. The chute score, exit score and vocalization were observed scored and recorded. The rectal temperature decreased from week 1 to week 2 and thereafter increased significantly but where higher in the hemp supplemented groups. The respiratory rate decreased in all the groups from week 1 to week two and there after increased significantly in all the groups but least in the (HH and HC) hemp supplemented groups. The heart rate also increased steadily across the hemp supplemented group with the normal range. The chute score elaborated a greater percentage of calmness, greater percentage of walking proportion and greater percentage of non-vocalizers in the hemp supplemented groups compared with the non-hemp supplemented group. It was concluded that hemp supplementation at pre- and post-weaning could improve the thermoregulation, respiratory efficiency and cardiac function as well as improving the behavior of the calves at weaning.

PSXIV-25 Investigating the Relationship Between Maternal Protectiveness and Temperament in Beef Cattle

Abstract Observations were made on 73 dams on two ranches in Colorado and one in Wyoming during the spring 2022 calving season to investigate the relationship between temperament and calf protection. The objective was to compare temperament scores to the distances of protective behavior performed by the dam as the observer moved closer to the pair. The protective actions of the cow were: Approach (alerted by raising her head to presence of the observer), Protective (moved between observer and calf), Vocalization (called to calf), and Closest (closest distance the observer reached before the pair moved away). Temperament scores included chute score, exit score, exit velocity, and blood lactate. One hundred percent of the dams alerted to the presence of the observer, twenty-five percent (n = 18) moved between the observer and the calf, and sixty-three percent (n = 46) vocalized to their calf. Thirty-five (47.9%) dams allowed the observer to touch the calf, categorized as Touch, while the other thirty-eight (52.1%) walked away from the observer before contact with the calf, categorized as No Touch. In a linear model using Touch/No Touch as the predictor and the continuous variables of Approach, Protect, Vocalize, Closest, exit velocity, and blood lactate; only closest (P < 0.001) and exit velocity (P = 0.011) had significant differences (P < 0.05) between the means. Dams that allowed the observer to touch the calf, on average, exited the chute with greater velocity (P = 0.01). Blood lactate and exit velocity were predictors in a mixed model with Ranch as a random factor with Touch/No Touch as the outcome; no significant difference was found (P > 0.05). The Kruskal-Wallis test was performed individually on Approach, Protection, Vocalization, and Closest with predictor values of Ranch, date of birth (DOB), and hair whorl. A significant difference (P = 0.04) appeared between the medians of Closest when grouped by hair whorl; dams with abnormal hair whorls moved away from the observer at a greater distance. When divided by Ranch, there were differences (P < 0.001) in the average chute score. This study suggests that dams with a faster exit velocity are approachable in the field. Exit velocity is not a good indicator of how close an observer can get to a calf in the field. Attraction to novelty could have a larger role than previously thought in temperament. No impactful relationships were observed between the temperament of a dam and her maternal protectiveness. Ranchers can continue selecting for docile temperament without fear of decreasing maternal protection.

Effects of an Appeasing Substance Application at Weaning on Growth, Stress, Behavior, and Response to Vaccination of Bos indicus Calves.

An analog of a bovine-appeasing substance (BAS) was previously demonstrated to have calming effects, and it could be an alternative to alleviate the stress caused by weaning. Thus, the objective of this study was to evaluate the effects of BAS administration at weaning on growth, stress, behavior, and response to vaccination of Nellore calves. Eighty-six Nellore calves (40 females and 46 males) were abruptly weaned and randomly assigned into 1 of 2 treatments: (1) saline solution (0.9% NaCl; n = 43) and (2) BAS (Secure Catte, IRSEA Group, Quartier Salignan, France; n = 43). The solutions were topically applied (5 mL/calf) to the nuchal skin area of each animal. On d 0, before treatment application, calves were vaccinated against infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI3) virus, and bovine viral diarrhea virus types 1 and 2 (BVDV-1 and 2). Calves from each treatment were kept in different pastures for 15 d (time of BAS action) and then moved to a single pasture. Body weight (BW), blood samples, and temperament in the chute (entry score, chute score, and exit score) were collected on d 0, 3, 8, 15, 51, and 100, and behavior on pasture on d 1, 2, 4, 5, 6, 7, and 9. Calves assigned to BAS vs. Saline treatment tended to have greater BW on d 15 (p = 0.10), tended to have lower entry scores on d 8 and 51 (p = 0.10), and chute scores on d 8 (p = 0.07), and had lower exit scores on d 8 (p = 0.02). Calves assigned to BAS vs. Saline treatment also had greater time grazing on d 7 and 9 (p < 0.01), eating concentrate on d 2, 5, and 6 (p = 0.05), walking on d 1, 2, 5, and 9 (p < 0.01), standing and ruminating on d 2, 7 and 9 (p < 0.01), and playing on d 2, 4, 6, 7, and 9 (p < 0.01). Furthermore, they had lower time lying on 1 and 2 (p < 0.01), standing on d 5 and 9 (p < 0.01), and vocalizing on d 1 and 2 (p < 0.01). Calves assigned to BAS vs. Saline treatment had greater serum titter concentrations of PI3 t on d 15 and 51 (p = 0.05) and BVDV-1 on d 51 (p = 0.02). However, they had lower serum concentrations of cortisol on d 3 (p = 0.03). BAS administration did not affect (p ≥ 0.12) the serum titer concentration of IBR and BVDV-2 titers or the plasma concentration of haptoglobin and ceruloplasmin. The BAS administration improved BW, reduced temperament and serum cortisol concentration, and improved behavior and response to vaccination.

Relationship among cattle breed and anabolic implant protocol relative to feedlot performance: Growth, temperament, feeding behavior, carcass traits, and economic return

Recent research has suggested that different cattle breed types may respond differently to anabolic implant protocols of varying intensity. Therefore, the purpose of this research was to compare anabolic implant protocols in feedlot steers of 2 different breed types. Sixty steers were stratified by weight and breed in a 2 × 3 factorial design examining 2 different breeds: Angus (AN; n=38) or Santa Gertrudis influenced (SG; n=22), and 3 implant strategies: no implant (CON; n=20), a moderate intensity implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MI; n=20), or a high intensity implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; HI; n=20). Steers were randomly placed into pens equipped with GrowSafe bunks to collect dry matter intake and feeding behavior. All animals were fed the same diet. Weight, chute score, exit velocity, serum, rectal temperature, hip height and 12th rib fat thickness were collected approximately every 28 d over a 196 d period. Serum urea nitrogen (SUN) was evaluated as well. Total average daily gain was increased (P < 0.0001) in both the HI and MI steers compared to the CON steers by 29.4% and 26%, respectively. A treatment × breed interaction was observed (P < 0.0001) for hip height, with AN-CON steers being shorter (P < 0.0007) than AN-HI, SG-CON, SG-MI, and SG-HI steers. A breed × treatment interaction was observed (P < 0.004) for chute score and rectal temperature, with SG-HI and SG-MI steers having increased chute scores (P < 0.001) when compared to AN-HI, AN-MI, AN-CON, and SG-CON throughout the course of the trial. Additionally, SG-HI and SG-MI steers had an increased rectal temperature (P < 0.004) compared to AN-HI, AN-MI, AN-CON, and SG-CON steers. A breed effect was observed (P = 0.002) for SUN with AN steers having increased (P = 0.002) SUN concentration compared to SG sired steers, in addition to a treatment effect (P < 0.0001), with CON steers having a higher (P < 0.0001) SUN concentration than MI and HI steers, regardless of breed. The MI implant protocol increased net return per head, on average, by $97.28, regardless of breed, while the HI implant protocol increased net return by only $80.84. Taken together, despite the cattle breed types responding differently to the different anabolic implant protocols at times, a moderate intensity anabolic implant protocol was optimal in this experiment for steers raised in a temperate climate.

Influence of handling in corrals on the temperament of different breeds of beef cattle raised in Brazil.

The objective of the present study was to verify the effect of handling in corrals on the stress of beef cattle of Nelore, Caracu, and Guzerá breeds through the analysis of the relationship between behavioral traits, growth, and blood parameters. A total of 778 records of entry scores, chute scores, exit scores, flight speed, cortisol, glucose, lactate, live weight, and body condition scores were collected on steers and heifers of the three breeds, born between September and December. The animals came from the Advanced Beef Cattle Research Center of the Animal Science Institute. The variance analyses were performed using the GENMOD procedure. The PROC CORR estimated Spearman correlation coefficients for all traits studied, and the principal components analysis was performed according to the procedure PRINCOMP. Heifers had higher reactivity than steers, with higher behavioral scores and blood parameters. Overall, Caracu individuals demonstrated lower reactivity in comparison to Nelore and Guzerá. However, they presented high stress when they were restrained. The principal component analysis highlighted that behavioral traits and blood parameters were contrasted with growth traits; thus, this analysis can help selectors (livestock farmers) understand the importance of selecting less reactive animals and more easily choose the animals they want to select for breeding. Our results indicate that handling in corrals could be considered a stressful event for bovines. For this reason, measuring blood parameters and behavioral traits can compose necessary decision-making tools regarding changes and adequacies while handling events to reduce stress and consequently improve the herd's reactivity.

Association of maternal temperament and offspring disposition on growth performance.

Animal behavior is complex and varies in definition, depending upon specific traits under observation. Temperament is one component of behavior, that in cattle, is described as the level of fearfulness to a novel or threatening environment. Temperament is a heritable trait which is important since aggressiveness and docility contribute to reproductive success, growth, and carcass quality. We observed maternal temperament at calving and the subsequent influence, if any, on offspring disposition at weaning and their effects collectively on growth performance and carcass traits. Maternal behaviors at calving were observed at four locations within the University of Arkansas system. Cows were assigned a maternal disposition score (MDS) at calving; a scale from 1 to 5 in which aggression decreases. At weaning, calves were assigned a chute score (CS); a scale from 1 to 6 in which aggression increases. Both scoring systems have been previously established. Blood was collected during the 56-d backgrounding period postweaning for blood glucose analysis. Data were analyzed using GLIMMIX procedures of SAS (α = 0.05). The relationship between the two scoring systems was determined with a Pearson correlation (P = 0.22). Animal was the experimental unit and blocked by location for all dependent variables. Location, sex, diet, and MDS were included in the class as covariables for all growth performance and carcass data related to CS. Cows that were more aggressive birthed heavier calves (P < 0.01) compared to indifferent cows. Calves born to cows with either very aggressive or very attentive (MDS of 2 or 3, respectively) scores were heavier upon feedlot entry (P = 0.03) compared to those from indifferent or apathetic cows (MDS of 4 or 5, respectively). Calves defined as nervous and restless (CS of 3 and 2, respectively) were heavier at weaning compared to docile calves (P < 0.01). Restless calves were heavier compared to nervous calves upon arrival and exiting the feedlot (P ≤ 0.01). Calves that were docile at weaning had greater marbling compared to calves that were restless (P ≤ 0.01). Calves that were restless at weaning had greater lean muscle area compared to calves that were nervous (P = 0.05). No definitive relationship was determined between dam and calf temperament. However, the results suggest temperament does impact growth performance and carcass traits but whether the influence comes from the dam or calf temperament, specifically, remains unanswered.

Effects of temperament on reproductive performance of Bos taurus heifers enrolled in the 7-day CO-Synch + controlled internal drug release protocol.

Cattle temperament significantly impacts production traits such as reproduction. The objective of this study was to assess the effects of temperament on pregnancy rates to fixed-timed artificial insemination (TAI) in Bos taurus beef heifers. A total of 297 Angus influenced heifers from 3 different locations were evaluated for temperament based on chute score and exit velocity on the first day of the estrus synchronization protocol (d-9) and classified by temperament type based on temperament score (calm ≤ 3 < excitable). Pregnancy status was determined by transrectal ultrasonography approximately 40 d after TAI. Hair from the tail switch was collected at d-9 and at d0 (TAI) for cumulative cortisol evaluation. A subset of 43 heifers from location 3 had blood samples collected at all handling events and evaluated for cortisol concentrations. Overall, 71% of heifers were classified as calm whereas 29% as excitable. Pregnancy rates to TAI were reduced (P = 0.042) in excitable heifers compared to calm heifers (36% vs. 55%, respectively). Mean concentration of cortisol in the hair was reduced over time (P < 0.001) from d-9 (3.5 ± 0.3 pg/mg) to d0 (1.74 ± 0.3 pg/mg) in all heifers, regardless of temperament. In addition, excitable heifers had increased circulating concentrations of cortisol when compared to calm heifers in all handling events (P = 0.015). More interestingly, despite of temperament, concentrations of circulating cortisol were reduced as the protocol events progressed, with greater cortisol concentrations on d-9, intermediate on d-3, and lesser on d0 (P = 0.031). Therefore, the present study demonstrates that heifer temperament has negative effects in pregnancy rates to TAI programs. However, according to blood cortisol concentrations, no chronic stress response was detected due to cattle handling for the TAI protocol. In fact, blood cortisol concentration was reduced between the initiation and completion of the protocol, indicating that heifers were acclimated to handing. These results support the adoption of acclimation protocols and proper cattle handling as a strategy to increase fertility of heifers that are exposed to TAI.

Behavioural Traits in Bos taurus Cattle, Their Heritability, Potential Genetic Markers, and Associations with Production Traits.

Simple SummaryCattle have the potential to seriously injure humans and cause damage to property. The risk of cattle reacting in a dangerous manner can be reduced through genetic selection for cattle which have a better temperament. A literature search was undertaken which returned papers which met the criteria of “Bovine”, “Genetics” and “Behaviour” or terms therein. Behavioural traits were grouped and their heritability, genomic associations and correlations with production traits examined. It was found that heritability estimates were more accurate in studies with large populations (n > 1000). Gene associations with behavioural traits were found on all chromosomes except for chromosome 13, with associated SNPs reported on all chromosomes except 5, 13, 17, 18 and 23. Generally, it was found that correlations between behaviour and production traits were low or negligible, suggesting that genetic improvement can be undertaken without negatively affecting production. There was variation between the results of the studies examined, and this underlines that any genetic study is population specific. Thus, to assess the heritability, genetic associations with production and genomic areas of interest for behavioural traits, a large-scale study of the population of interest would be required.People who work with cattle are at severe risk of serious injury due to the size and strength of the cattle. This risk can be minimised by breeding less dangerous cattle, which have a more favourable reaction to humans. This study provides a systematic review of literature pertaining to cattle genetics relating to behaviour. The review protocol was developed using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) framework, with Population, Exposure and Outcome components identified as Bovine, Genetics and Behaviour respectively. Forty-nine studies were identified in the sifting and assigned non-exclusively to groups of heritability (22), genomic associations (13) and production traits related to behaviour (24). Behavioural traits were clustered into the following groups: “temperament, disposition and/ or docility”, “aggression”, “chute score”, “flight speed”, “milking temperament”, “non-restrained methods” and “restrained methods”. Fourteen papers reported high accuracy (Standard Error ≤ 0.05) estimates of heritability, the majority (n = 12) of these studies measured over 1000 animals. The heritability estimates were found to vary between studies. Gene associations with behavioural traits were found on all chromosomes except for chromosome 13, with associated SNPs reported on all chromosomes except 5, 13, 17, 18 and 23. Generally, it was found that correlations between behaviour and production traits were low or negligible. These studies suggest that additive improvement of behavioural traits in cattle is possible and would not negatively impact performance. However, the variation between studies demonstrates that the genetic relationships are population specific. Thus, to assess the heritability, genetic associations with production and genomic areas of interest for behavioural traits, a large-scale study of the population of interest would be required.

311 Administering a Bovine Appeasing Substance to Beef Heifers During an Estrous Synchronization Protocol and its Impacts on Temperament and Pregnancy Rate

Abstract This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to Bos taurus (angus crossed) beef replacement heifers at the initiation of an estrous synchronization (TAI) protocol on their temperament and pregnancy rates. A total of 348 heifers at four locations were stratified by body weight (BW); reproductive tract score (RTS), and temperament score [TS; average of exit velocity (EV) and chute score (CS), determined at the day of initiation of TAI) and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 173) or placebo (water; CON; n = 175). Treatments (5 mL) were topically applied to the nuchal skin area of each heifer at the initiation of the TAI protocol. Within location, heifers were allocated to pens (6 pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration during the duration of the experiment. Temperament (EV, CS) was assessed three times (days 0, 7 and 9) during the TAI protocol by the same trained technician. Pregnancy rate was determined by ultrasonography between days 45 and 55 post TAI. Heifer BW (379.5±5 kg), RTS (3.8±0.06), CS on days 0, 7 and 9 (2.33±0.06, 2.08±0.04, and 1.91±0.04, respectively), and EV on days 0, 7 and 9 (1.35±0.03, 1.28±0.03, and 1.39±0.03 m/s, respectively), and estrus expression prior to TAI (40.2±5.9%) were similar (P&amp;gt;0.10) between treatments. Pregnancy rate to TAI differed among locations (P&amp;lt; 0.05); however, it was not affected by treatment (39.7±8.2% and 41.0±3.7% for CON and BAS, respectively), with no treatment by location interaction. In conclusion, administration of BAS to beef heifers at the initiation of a TAI protocol did not alter temperament, measured as CS and EV, and failed to increase pregnancy rates.

PSI-15 Effects of Melatonin on Behavioral and Physiological Responses of Weaned Beef Calves

Abstract Weaning is a stressful event often associated with changes in physiological characteristics, increased restlessness, reduced feed intake, and poor performance. This study was designed to evaluate the effects of melatonin on behavioral and physiological responses of weaned beef calves. Angus beef calves (n=36) at 7-mo of age were stratified by dam parity, body weight, calf sex and randomly allocated to receive either 24mg melatonin implants (MEL) or physiological saline (CON). A subset of calves were fitted with accelerometers on the hind leg to monitor activity levels for 7 days after weaning. Blood samples, rectal temperature, chute score and body weight measurements were collected on d 0, 7 and 14 after weaning. Activity of MEL calves was significantly (P &amp;lt; 0.05) lower than CON. The MEL calves had lower (P &amp;lt; 0.05) chute score on d 7 and 14 compared to CON. There was no marked effect of melatonin on rectal temperature and hematological parameters, however, platelet showed significant (P &amp;lt; 0.05) difference with MEL recording higher values compared to CON. Average daily gain (ADG) was 1.67 and 2.35kg/d in CON and MEL, respectively. We concluded that although no differences in ADG, hemogram, and rectal temperature were observed, melatonin treated calves had reduced behavioral stress response associated with weaning.

235 Animal Production and Carcass Traits Affect Meat Quality and Flavor Through Metabolomics

Abstract Untargeted metabolomics focuses on the detection of as many groups of metabolites as possible to obtain patterns or fingerprints of biological phenomena. Hundreds or even thousands of metabolites can be measured, utilizing advanced chemistry detection techniques such as high-performance liquid chromatography – quadrupole time of flight (HPLC-qTOF). Statistical analyses are utilized to narrow the number of metabolites from thousands to just those that are statistically impactful on the applied treatments. This smaller number of compounds (100 to 200) may then be analyzed statistically using various multivariate approaches to then identify those influenced by applied treatments. When analyzing serum from either Angus or Brahman cattle that were segregated into three temperament treatments based on chute scores, differential upregulation of metabolites was found between the two breed types and the temperament scores. It appears that in Angus cattle, the most temperamental cattle had significantly upregulated metabolites according to the heatmap, while Brahman cattle showed downregulated metabolites in individual animals in both the Intermediate and Temperamental temperament scores. In a separate study to illustrate the impact of metabolomics on meat quality, 18 USDA Select and 18 USDA Choice strip loins were collected and then aged for either 10 or 20 d post-processing. Furthermore, steaks from each quality grade and aging treatment were then cooked to either 63, 71, or 80oC internal temperature. Samples from the interior of each steak that excluded the exterior seared surface were analyzed. In a Principal Components Discriminant Analysis of the significant metabolites, all treatment combinations within 10 or 20 d aging were evenly split on either side of the vertical centerline with Principal Component 1 (50.5%) pulling the metabolites apart. In particular, Select steaks cooked to the two higher internal temperatures were pulled the furthest apart. Metabolomics is a relatively new but effective technology in determining cause and effect for commonly-known factors that impact meat quality.

PSXIII-B-9 Effects of Hemp (Cannabis Sativa) Supplementation on Behavior, Heart Rate, Hemogram and Serum Biochemistry Profiles of Beef cow-Calf Pairs During Weaning

Abstract Weaning is a stressful event that affects animal welfare and performance. This study examined the effects of industrial hemp (Cannabis sativa) supplementation on behavior, chute score and physiological responses of cow-calf pairs during weaning. Ten apparently healthy Angus cow-calf pairs, average BCS of 6.0, were randomly allocated to one of two groups for 7 days: Control (CON, 200g/head of commercial grower feed, n=10) and Hemp (HMP, 200g/head containing 80% commercial grower feed containing 20% hemp, n=10), daily. Hay and water were provided ad libitum. Chute and exit scores were recorded and blood samples were collected at d 0, 4 and 7 of the feeding period. Animal activity data was recorded using automated activity monitoring systems Moomonitor and IceQubes for cows and calves, respectively. At weaning, cow-calf pairs were separated abruptly and observed. Data was analyzed using Stata 14.2. Overall, rectal temperature, respiratory rate, rumination duration, rumen fluid pH and activity did not differ (P &amp;gt; 0.05) between treatments. Specifically, hemogram and serum biochemistry results did not differ (P &amp;gt; 0.05) between cow groups. However, resting duration tended to be greater in HEMP compared with CON (383.94±19.3 vs 298.60±16.1 mins/day, P = 0.06) cows. In addition, feeding duration was greater in HEMP compared with CON (473.8±24.5 vs 262.3±31.6 min/day) cows. In calves, heart rate was lower in HEMP compared with CON (62.67 vs 94.7 beats/min, P = 0.03). Hemoglobin concentration was smaller in HEMP compared with CON (12.6 vs 14.1mg/mL, P = 0.02). However, mean corpuscular hemoglobin concentration was greater in HEMP compared with CON (33.04 vs 32.04g/dl, P = 0.04). We concluded that hemp supplementation increased resting and feeding duration of cows, and reduced heart rate of calves during weaning. This is the first report on the use of hemp to improve welfare of cow-calf pairs during weaning.

PSI-10 Effect of Chronic Melatonin Supplementation During mid to Late Gestation on Performance and Behavioral Responses of Cows Exposed to Summer Heat Stress

Abstract Summer heat stress negatively impacts the health and welfare of animals. Melatonin is a highly potent antioxidant and free radical scavenger with immune modulation and anti-inflammatory effects in domestic animals. This study examined the effect of supplemental melatonin during mid to late gestation on serum cortisol, heat shock protein 90 (HS90) and glucose concentrations, performance, behavior and hemogram of pregnant cows and their offspring. Multiparous pregnant beef cows were randomly assigned to 1 of 2 groups and supplemented with Melatonin® implants 24 mg (MEL, n=13) or without (CON, n=12) at day 190, 218, and 246 of gestation. Also, offspring performance (n = 24) was evaluated. Body weight, rectal temperature, hemogram, behavioral responses of cows (chute score, vocalization and exit score) were scored biweekly for 16 weeks. The average daily gain (ADG), rectal temperature, glucose concentration and hemogram of cows and calves showed no significant difference (P&amp;gt;0.05) between treatments except in calves were platelet were higher in MEL treated calves than control. Cortisol levels were significantly lower (P&amp;lt; 0.05) in MEL cows compare to CON from day 14 (1437 ± 2.54 and 2028 ± 3.23 pg/ml respectively) to the end of the experiment. Also, serum HSP90 concentrations were significantly lower (P&amp;lt; 0.05) from day 14 to the end of the study period (0 ng/ml and 0.73 ng/ml respectively). Chute and exit score did not differ significant between groups. Our results revealed that chronic melatonin supplementation during mid to late gestation reduced serum cortisol and HSP90 in cows exposed to summer heat stress.

Effects of Temperament on the Reproduction of Beef Cattle.

Simple SummaryIn beef cattle and other livestock species, temperament can be considered as their behavioral responses to human interaction. Temperament evaluation allows classifying cattle according to the level of responsiveness, from calm to excitable. Consistently across studies, beef females classified as more excitable have signs of increased stress response and are less fertile compared to cohorts with calmer temperament. Cattle temperament can be improved via genetic selection and acclimating young animals to human interaction and handling procedures.Temperament is often defined as the behavioral expression of animals in response to human interaction. Cattle temperament can be evaluated using an association of chute score and exit velocity, with cattle then classified as adequate or excitable temperament. To assess the impacts of temperament on various beef systems, these evaluation criteria were associated with productive and reproductive parameters of Bos taurus and B. indicus-influenced cattle. Consistently across studies, excitable cattle had greater plasma cortisol compared to animals with adequate temperament. Studies also reported that excitable beef females have poorer reproductive performance compared to calmer cohorts, including reduced annual pregnancy rates, decreased calving rate, weaning rate, and kg of calf weaned/cow exposed to breeding. Acclimating B. indicus × B. taurus or B. taurus heifers to human handling improved behavioral expression of temperament and hastened puberty attainment. However, similar benefits were not observed when mature cows were acclimated to human handling. Collectively, temperament of beef females measured via behavioral responses upon human handling impacts their reproductive and productive responses independent of breed type, and should be considered for optimal beef cattle production.

Vascular perfusion and the volume of the preovulatory follicle are affected by the temperament of Nellore cows

The aim of this study was to evaluate the effect of temperament on vascular perfusion and morphological characteristic (volume) of the preovulatory follicle (POF) and corpus luteum (CL) of Nellore cows submitted to timed artificial insemination (TAI). The effect of temperament on cortisol, P4 concentrations and on ovulation rates was also evaluated. To achieve this, the ovarian cycles of 201 beef cows were synchronized, and temperament assessments were carried out using the chute score and chute exit score at the time of TAI. According to the individual scores, the animals were classified into adequate temperament (ADQ) or excitable (EXC). Blood samples were collected at the time of TAI and 7 days later to measure cortisol and P4, respectively. Color Doppler ultrasound assessments were performed to determine the volume, and blood flow of the POF and CL at the time of TAI (D0) and seven days later (D7), respectively. The ovarian cycle synchronization and ovulation rates were compared between the ADQ and EXC groups using the chi-square test while hormonal concentrations and ultrasound variables were compared using a general linear model. Multiple comparisons between groups were conducted using Tukey's contrasts. The data were expressed as means and standard error. The number of color pixels (p ≤ 0.01), intensity of color pixels (p ≤ 0.01) and volume (p ≤ 0.01) in the POF were all lower for the EXC group. However, cortisol concentrations were higher in the EXC group compared to the ADQ (p ≤ 0.01). This was related to stress during TAI management. The number and intensity of the color pixels in the CL showed no difference between groups, however, the volume was lower (p ≤ 0.01) for the EXC group. There was no difference between groups regarding ovarian cycle synchronization, ovulation rates and P4 concentration. However, the P4/CL volume ratio was higher in the EXC group. The results indicate that the excitable temperament in Nellore cows has important endocrine effects and reflects on the ovarian structures, with less follicular blood flow and a reduction in the volume of the POF and CL, however, without compromising the ovulation rate.

PSIV-15 Examining the relationship between breed type and anabolic implant protocols in performance in the feedlot, health, and temperament of beef steers

Abstract The purpose of this research was to compare anabolic implant protocols in feedlot steers of two different breed types. Sixty steers were stratified by weight and breed in a 2 x 3 factorial design examining two different breeds: Angus (AN; n = 38) or Santa Gertrudis influenced (SG; n = 22), and three implant strategies: no implant (CON; n = 20), a moderate implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MOD; n = 20), or a vigorous implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; VIG; n = 20). Steers were randomly placed into pens equipped with GrowSafe® bunks and fed the same ration. Weight, chute score (CS), exit velocity, blood, temperature, hip height and 12th rib fat thickness were collected approximately every 28d over a 112d period. Over the 112 d, SG steers tended (P = 0.10) to gain more hip height than AN steers. Anabolic implant protocol influenced total gain with both VIG and MOD steers gaining more (P &amp;lt; 0.01) than CON. On d 0, SG steers had a higher (P &amp;lt; 0.01) CS compared to AN steers, with this being maintained through the course of the trial. There was also as a tendency for there to be a breed*treatment effect (P = 0.06) on d112, with SG-MOD having a higher (P = 0.04) CS than AN-VIG, and a tendency (P = 0.08) for SG-VIG to have a higher CS than AN-VIG. Moderate and VIG implant protocols may be a useful tool to increase performance in feedlot steers. However, this research did find that SG influenced steers may have a more excitable temperament, but implant protocol did not influence (P &amp;gt; 0.05) temperament.

PSX-B-17 Appeasing substance application at weaning enhanced growth and temperament of bos indicus-influenced weaned calves in grazing system

Abstract The objective of this study was to evaluate the effects of a synthetic analogue of the bovine appeasing pheromone (i.e. bovine appeasing substance; BAS) on growth and temperament of weaned calves grazing Capim-Marandú (Urochloa brizantha cv Marandú). At weaning (d 0), 86 calves (47 steers and 39 heifers; Aberdeen Angus ′ Nelore; 8 ± 1 mo) were stratified by body weight (197.9 ± 24.9 kg) and randomly assigned to receive a single dose of BAS (n = 43; SecureCattle; Nutricorp, Araras, SP, Brazil) or saline (CON; n = 43; saline 0.9% NaCl). Treatments (5 ml) were topically applied to the nuchal skin area of each animal on d0. Body weight was collected on d 0, 8, 15, 51 and 100. Chute score (1 to 5; 1 = calm, no movement; 5 = violent and continuous struggling) and chute entrance and exit scores (1 to 3; 1 = slow; 3 = fast) were collected on d 3, 8, 15, 51 and 100. Scores were averaged across 3 trained technicians. Data were analyzed using the MIXED procedure of SAS. Calves assigned to BAS treatment had greater (P &amp;lt; 0.01) average daily gain (ADG) from d 8 to 15 (0.158 and -0.284 kg/d ± 0.07). Calves assigned to BAS treatment tended (P = 0.10) to have lower chute entrance score on d 8 and 51 and had lower (P = 0.02) chute exit score on d 8 than calves assigned to CON treatment. Additionally, calves assigned to BAS treatment tended (P = 0.07) to have lower chute score on d 8 when compared to calves assigned to CON treatment. The application of BAS at weaning improved calf ADG and improved calf temperament as observed by chute score and chute entrance and exit scores, suggesting that BAS application has calming effects.