Impacts of temperament on Nellore cattle: physiological responses, feedlot performance, and carcass characteristics

Characterization of the Temperament and Reactivity of Nelore Cattle (Bos indicus) Associated with Behavior Scores during Corral Management in the Humid Tropics

The evaluation of the reactivity and distress of cattle during corral management, by means of subjective scores, aims at the standardization of behavioral indicators, through non-invasive methods, in addition to enabling the development of more appropriate management practices, thus promoting the comfort and well-being of these animals. Therefore, in this study, we aimed to characterize the temperament and distress of cattle managed in a corral using behavioral indicators during the rainiest period. For this, the experiment was conducted on a property located in the municipality of Mojuí dos Campos, during the rainiest quarter (February-April). Thus, 30 male cattle, not castrated, approximately 29 months of age, clinically healthy, and weighing 310 + 20 kg, were divided into three rearing systems: silvopastoral (SP), traditional (SS), and integrated (SI) systems. There were 10 animals per system. Physiological parameters were collected to evaluate rectal temperature (RT) and respiratory rate (RR), as well as body surface temperature (BST), through thermal windows (head and flank infrared temperature and rump infrared temperature). To evaluate temperament and reactivity, scores indicative of corral behavior were used, namely escape speed (ES), tension score (SS_1), tension score (SS_2), reactivity scale (RS), movement score (MS), and temperament scale (TS). The results showed that there was a thermal amplitude of 5.9 °C on average and 8.6 °C at maximum when comparing the structure of the corral and the trees. In addition, the comparisons between the production systems for the behavioral variables did not differ at the 5% significance level, except for ES, where the traditional system differed from the integrated system and the silvopastoral system, showing intermediate average values for both. In addition, there was a positive correlation between the variables RT and RR (r = 0.72; p < 0.01), RR and SS_2 (r = 0.38; p = 0.04), flank infrared temperature and MS (r = 0.47; p = 0.01), rump infrared temperature and RS (r = 0.37; p = 0.04), SS_1 and RS (r = 0.41; p = 0.02), SS_1 and SS_2 (r = 0.39; p = 0.03), RS and SS_2 (r = 0.58; p = 0.00), RS and MS (r = 0.50; p = 0.01), RS and TS (r = 0.61; p = 0.00), SS_2 and MS (r = 0.51; p = 0.00), SS_2 and TS (r = 0.47; p = 0.01), and MS and TS (r = 0.44; p = 0.02), and a negative correlation between ES and TS (r = -0.42; p = 0.02). The rainy season had a major influence on the evaluation of temperature and distress levels during handling in the corral, as evidenced by the association between physiological and behavioral parameters.

Factors intrinsic to handling and transport in pre-slaughter behavioural changes in beef cattle

The aim of this study was to evaluate handling and transport variables as potential causes of disturbed behaviour in response to seeing a person on an overhead observation platform during pre-slaughter in batches of females and castrated males composed of pure or crossed Bos Taurus animals (Aberdeen Angus, Red Angus, Hereford and Charolais) with a maximum of 37.5% Bos indicus, and maturity at slaughter varying from zero to eight teeth, coming from pasture and confined systems. For the batches of castrated males, the independent variables included the distance covered on the trip, and the handling and facilities on the farms. For the female batches, the variables were travel time and waiting time prior to unloading. For both sexes, the presence of horns in the batches and the load density were included in the regression equations. Disturbed behaviour, the result of factors related to animal handling and transportation, is detrimental to satisfactory results in production systems. It is up to the managers in the production chain to seek alternatives in order to minimise inappropriate behaviour, which is one determinant of loss. Handling and transport are determining factors in the behaviour of beef cattle during the pre-slaughter period.

The effect of succinate on color stability of Bos indicus bull meat: pH-dependent effects during the 14-day aging period

Bos taurus indicus bulls are very susceptible to pre-slaughter stress, which directly impacts the decline in muscle pH, leading to darker meat. The aim was to investigate the effect of succinate and atmosphere on the color stability of Nellore (Bos taurus indicus) Longissimus lumborum steaks classified by ultimate pH (pHu): normal pHu (5.40 ≤ pHu ≤ 5.79) and high pHu (pHu ≥ 5.80). The experimental treatment systems were: (i) vacuum packaging without succinate injection, (ii) HiOx-MAP (80 % O2 + 20 % CO2), and (iii) HiOx-MAP (80 % O2 + 20 % CO2) enhanced with sodium succinate injection (pH 5.4). Steaks from all treatment systems were stored at 4 °C for 14 days and tested for instrumental color, myoglobin content, oxygen consumption (OC), metmyoglobin-reducing activity (MRA), lipid oxidation, and microbiological analysis. High and normal pHu vacuum-packaged steaks exhibited greater color stability due to higher MRA. High and normal pHu steaks packaged with HiOx-MAP or HiOx-MAP enhanced with succinate showed improved color due to lower deoxymyoglobin content (%DMb) and OC up to the eighth day of storage. Still, succinate injection promoted increased (P < 0.05) lipid oxidation in normal pHu steaks and reduced MRA after 14 days. These findings emphasize the intricate interplay between pHu and packaging systems on Bos taurus indicus meat quality. Further research in this area could contribute to a better understanding of meat color abnormalities and provide insights into potential meat preservation and enhancement strategies.

Calming Hungarian Grey Cattle in Headlocks Using Processed Nasal Vocalization of a Mother Cow

Sound analysis is an important field of research for improving precision livestock farming systems. If the information carried by livestock sounds is interpreted correctly, it could be used to improve management and welfare assessment in this field. Therefore, we hypothesized that the nasal vocalization of a mother cow could have a calming effect on conspecifics. The nasal vocalization in our study was recorded from a mother cow (not part of the test herd) while it was licking its day-old calf. The raw sound was analyzed, cleaned from noises, and the most representative vocalization was lengthened to two minutes. Thirty cows having calves were randomly selected from eighty Hungarian grey cattle cows. Two test days were selected, one week apart; the weather circumstances in both days were similar. The herd was collected in a paddock, and the test site (a restraining crate with a headlock) was 21 m away from them. The cows from the herd were gently moved to the restraining crate, and, after the installation of the headlock, Polar® heart rate monitors were fixed on the animals. The recording of the RR intervals was carried out for two minutes. On day one of the test, the processed nasal sound was played to every second cow during the heart rate monitoring. When the sound ended, the heart rate monitor was removed. On test day two, the sound and no sound treatments were switched among the participating cows. At the end of the measurement, the headlock was opened, letting the animals out voluntarily, and a flight test was performed along a 5 m distance. The time needed to pass the 5 m length was measured with a stopwatch and divided by the distance. The RR intervals were analyzed with the Kubios HRV Standard (ver. 3.5.0) software. The following data were recorded for the entire measurement: average and maximum heart rate; SD1 and SD2; pNN50; VLF, LF, and HF. The quasi-periodic signal detected in the sound analyses can hardly be heard, even when it is enhanced to the maximum. This can be considered a vibration probably caused by the basis of articulation, such as a vibration of the tongue, for example. The SD2/SD1 ratio (0.97 vs. 1.07 for the animals having no sound and sound played, respectively, p = 0.0110) and the flight speed (0.92 vs. 1.08 s/m for the animals having no sound and sound played, respectively, p = 0.0409) indicate that the sound treatment had a calming effect on the restrained cows. The day of the test did not influence any of the measured parameters; therefore, no effect of the routine was observed. The yes-no sequence of the sound treatment significantly reduced the pNN50 and flight speed values, suggesting a somewhat more positive association with the headlock and the effectiveness of the processed nasal sound. In conclusion, we have demonstrated that, by means of sound analyses, not only information about individuals and the herd can be gathered but that, with proper processing, the sound obtained can be used to improve animal welfare.

Probability and number of bruises in bovine carcasses according to animal type, handling and transport

The aim of this study was to evaluate pre-slaughter risk factors on the probability of bruising and the number of bruises in different regions of the bovine carcass. The study evaluated the data from 4061 batches of slaughtered cattle, totalling 199,026 carcasses, from Hereford and Aberdeen Angus animals in crosses with continental European breeds and Zebu cattle. The factors that caused injury were sex, handling conditions (score), vehicle type, vehicle load density (kg/m2), travel time (minutes), travel distance (kilometres), physiological maturity (dentition), animal reactivity (score), and carcass fat (score). The type of vehicle had the greatest influence on the probability of carcass bruising and affected all carcass cuts. More bruising occurred in vehicles with a greater load capacity. A higher chance of bruising was seen in groups of older animals, those with an excitable temperament and, especially, in groups of females. Higher load densities during transport resulted in a greater chance of bruising occurring in all cuts except the hindquarters. Distance and travel time are unstable in the models, but also detrimental, increasing the probability of bruising and the number of bruises in the various cuts. The results of this study suggest that good practices in the welfare, handling and transport of the animals, as well as training the personnel responsible for their handling, should be adopted to minimise the risk of injury at different locations on the carcass.

Contemporary Knowledge on the Assessment of Temperament in Cattle and Its Impact on Production and Reproduction Including Some Immunological, Genetic and Metabolic Parameters

Temperament is associated with the well-being, health, production and reproduction of cattle. In order to increase the population of individuals with the desired temperament, its evaluation should be standardized and be made one of the obligatory elements of breeding and veterinary examination. A number of different tests are used for temperament assessment. In this article, the importance of temperament correlation with some metabolic, genetic, immunological, production and reproductive parameters have been shown, pointing at its influence on the economy and cattle handling. The most common methods for assessing the temperament of cattle are presented, including long-time scales of temperament assessment. At the same time, the relationship of the temperament of cattle with production efficiency, immunity and reproductive indicators has been shown, indicating that its correct assessment is an important aspect of the proper development of the herd and the associated economic growth.

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.

Genetic parameters for behavioral and growth traits of Nellore cattle

The growing concern of consumers with the welfare of production animals searches welfare in a production system extremely important; thus, the study of animal temperament is necessary to select less excitable temperament animals resulting in healthy development and fewer accidents. The objective of this study was to estimate genetic parameters for traits related to animal temperament and growth traits of Nellore cattle. In addition to exploring the genetic pattern of these traits through cluster and principal component analysis (PCA), to reveal possible groups of individuals that express less excitable temperament and greater growth. A total of 2,332 measurements from 1,245 male and female Nellore cattle born between 2008 and 2016 were utilized in the study. The (co)variance components were estimated by Bayesian inference using a two-trait animal model. The heritability for temperament score (TS), flight speed (FS), body condition score (BCS), live weight (LW), and hip height (HH) were 0.08, 0.12, 0.06, 0.13, and 0.48, respectively. The genetic correlation between the temperament indicator traits was strong and positive (0.78 ± 0.24). The TS and FS showed a favorable or null genetic correlation with LW, BCS, and HH. The third cluster included animals with low EBV for TS and FS and with high EBV for BCS, LW, and HH. In the PCA, the PC1 was what best evidenced the aim of this study; thus, our findings suggest that we could explore select animals based on cluster 3 and PC1 in breeding programs to select Nellore cattle with less excitable temperament and greater growth.

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.

Connecting Heat Tolerance and Tenderness in Bos indicus Influenced Cattle

Bos indicus cattle are widely utilized in tropical and subtropical climates. Their heat tolerance and parasite resistance are integral for beef production in these regions; however, a reputation for excitable temperaments, slower growth, and variation in tenderness has limited their use in commercial beef production. This suggests that there is antagonism between heat tolerance and meat production traits. Meat quality characteristics are determined by the properties of skeletal muscle as well as conditions during slaughter and processing. Thus, it is possible that adaptations related to heat tolerance in the living animal affect tenderness and other meat quality attributes. Since muscle represents a large proportion of body mass, relatively small changes at the cellular level could impact overall heat production of the animal. Specifically, protein degradation and mitochondria function are aspects of organ and cellular metabolism that may help limit heat production and also have a connection to tenderness. Protein degradation postmortem is critical to structural changes that enhance tenderness whereas mitochondria may influence tenderness through their roles in energy metabolism, calcium regulation, cell death signaling, and oxidative stress. This review explores potential relationships between cellular metabolism in vivo and beef quality development in Bos indicus and Bos indicus influenced cattle.

Effect of Different Finishing Strategies and Steer Temperament on Animal Welfare and Instrumental Meat Tenderness

Simple Summary

Animal welfare is one of the most important quality attributes for meat consumers and a potential tool for differentiation in farms where husbandry is based on extensive rearing systems and high animal welfare standards. However, there is not enough contextualized scientific information in relation to these systems and some others that are emerging, with a higher level of intensification. In this experiment, we compared animal welfare between different fattening systems, through the combination of several indicators regarding physiology, behavior, health, productivity, and meat tenderness. Animal temperament, as well as its impact on welfare and meat quality, was also considered. From our results, we concluded that finishing strategies based on pastures that ensure an adequate level of nutrition and health would be more appropriate for fattening animals, from both the animal welfare and the meat quality perspectives. Intensification up to certain levels (pasture plus supplement), without deprivation of certain behaviors and with constant monitoring of health, should provide productive benefits without compromising animal welfare. In confined systems with 9 m² per animal, the challenge is greater in relation to animal welfare because of restrictions of important behaviors and greater risks of dietary diseases. It is considered that, if some conditions of the confined system are improved, such as the space available per animal and the strict prevention and constant monitoring of diet disorders, it could be a valid alternative for fattening cattle. Temperament could be improved through good handling, with positive impacts on welfare, productivity, and meat tenderness.

Abstract

The aim of this experiment was to evaluate the effect of different fattening systems from pasture to concentrate and temperament on animal welfare (AW) and meat quality (MQ). Eighty-four Hereford steers were randomly assigned to the following groups: T1, pasture (4% of animal live weight: LW); T2, pasture (3% LW) plus concentrate (0.6% LW); T3, pasture (3% LW) plus concentrate (1.2% LW); T4, an ad libitum concentrate treatment. Temperament was assessed by three individual tests: crush score, flight time, and exit speed, building a multicriterial temperament index (TIndex). The flight zone was also registered for each treatment. AW was assessed through the integration of indicators of productivity, physiology, and behavior, as well as by monitoring the health status within each treatment. Shear force was registered for MQ. Differences in average daily gain were due to the different energetic composition of the diets (T4 > T3 > T2 > T1) and were not attributable to animal welfare problems. Animals from T4 had the higher average daily gain (ADG) but welfare was negatively affected, being evident through physiological indicators, the restriction or deprivation of relevant behaviors, diet-related diseases, and mortality. T1, T2, and T3 did not appear to compromise animal welfare. However, strict preventive measures and monitoring should be taken during the habituation process and when using any new diet that includes concentrate, because of possible dietary diseases. Shear force values were lower in T1. None of the animals in our experiment were excitable or aggressive, but there was a positive response to handling in all treatments. In addition, regardless of diet, calmer animals had higher average daily gain and lower shear force values; thus, temperament appears to have a significant influence on productivity and meat quality.

Adrenergic Tone as an Intermediary in the Temperament Syndrome Associated With Flight Speed in Beef Cattle

The temperament of farm animals can influence their resilience to everyday variations within the managed production environment and has been under strong direct and indirect selection during the course of domestication. A prominent objective measure used for assessing temperament in beef cattle is the behavioral flight response to release from confinement in a crush or chute. This behavioral measure, termed flight speed (also known as escape velocity) is associated with physiological processes including body temperature, feeding behavior, growth rate, carcass composition, immune function, and health outcomes. This review examines the functional links between this suite of traits and adrenergic activity of the sympathetic nervous system and the adrenomedullary hormonal system. It is suggested that flight speed is the behavioral aspect of an underlying “flightiness” temperament syndrome, and that elevated adrenergic tone in animals with a high level of flightiness (i.e., flighty animals) tunes physiological activities toward a sustained “fight or flight” defense profile that reduces productivity and the capacity to flourish within the production environment. Nonetheless, despite a common influence of adrenergic tone on this suite of traits, variation in each trait is also influenced by other regulatory pathways and by the capacity of tissues to respond to a range of modulators in addition to adrenergic stimuli. It is suggested that tuning by adrenergic tone is an example of homeorhetic regulation that can help account for the persistent expression of behavioral and somatic traits associated with the flight speed temperament syndrome across the life of the animal. At a population level, temperament may modulate ecological fit within and across generations in the face of environmental variability and change. Associations of flight speed with the psychological affective state of the animal, and implications for welfare are also considered. The review will help advance understanding of the developmental biology and physiological regulation of temperament syndromes.

Calm Hu ram lambs assigned by temperament classification are healthier and have better meat quality than nervous Hu ram lambs

The objective of this study was to evaluate the effects of temperament classification (assessed using an arena test) on health and productivity of Hu ram lambs. In experiment one, eight ram lambs classified as calm and eight classified as nervous (selected from 100 ram lambs) were fed individually for 60-days to compare food intake, food digestibility, weight gain, and biochemical indices of health. In experiment two, nine ram lambs classified as calm and nine classified as nervous (selected from 150 ram lambs) were fed in a group and slaughter traits, meat quality, and muscle histology were compared. Calm lambs had higher dry matter digestibility, lower serum TNF-α, higher total antioxidant capacity, higher total superoxide dismutase activity, higher dressing percentage, higher cross-sectional area of loin, higher myofibre density, lower ultimate pH of the meat, and higher meat redness, than nervous lambs. Selection for calm temperament could be beneficial to health, slaughter, and carcass traits in Hu ram lambs.

Administering an appeasing substance to beef calves at weaning to optimize productive and health responses during a 42-d preconditioning program

This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to beef calves at weaning on their performance, physiological responses, and behavior during a 42-d preconditioning program. Eighty calves (40 heifers and 40 steers; 90% British × 10% Nellore) were weaned at 233 ± 2 d of age (day 0); ranked by sex, weaning age, and body weight (BW); and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal following dam separation. Within treatment, calves were allocated to one of eight drylot pens (four pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration (TMR) from day 0 to 42, intake of which was assessed daily. Live behavior observations were conducted on days 1, 2, 4, 8, 16, and 32. Temperament was assessed and blood samples were collected via jugular venipuncture on days -21, 0, 3, 7, 14, 28, and 42. Hair samples were collected from the tail switch on days 0, 14, 28, and 42. Calves were vaccinated against bovine respiratory disease viruses on days -21 and 0. Average daily gain from day 0 to 42 did not differ between treatments (P = 0.57) but was greater (P = 0.05) in BAS vs. CON calves from day 0 to 28. Intake of TMR was greater (P = 0.05) during the first week for BAS vs. CON calves (treatment × week; P = 0.08). The mean proportion of calves feeding simultaneously and performance of social and play behaviors were greater (P ≤ 0.05) for BAS vs. CON calves. Escape attempts were greater (P < 0.01) for BAS vs. CON calves on day 1 (treatment × day; P = 0.03). Exit velocity was greater (P = 0.04) for CON vs. BAS calves on day 14 and tended (P = 0.10) to be greater for CON vs. BAS calves on day 7 (treatment × day; P = 0.03). Mean plasma concentrations of haptoglobin were greater (P = 0.02) in CON vs. BAS calves. Hair cortisol concentrations were greater (P = 0.05) in CON vs. BAS calves on day 14 (treatment × day; P = 0.03). Mean serum concentrations of antibodies against bovine viral diarrhea virus were greater (P = 0.02) in BAS vs. CON calves. Collectively, BAS administration to beef calves at weaning alleviated stress-induced physiological reactions, improved temperament evaluated via chute exit velocity, enhanced humoral immunity acquired from vaccination, and appeared to have accelerated adaptation to novel management scheme and environment.

Relationships between temperament, meat quality, and carcass traits in Nellore cattle1

The aim of this study was to evaluate the relationship between temperament in Nellore bulls with carcass and meat quality traits. In total, 1,400 bulls were studied, and temperament was assessed using two measurements: movement score (MOV) and flight speed test (FS). Both MOV and FS were measured at two time points, with background (MOVb and FSb) temperament measured at yearling age, ~550 d after birth, and the preslaughter (MOVps and FSps) temperament measured at the end of the feedlot period. The change of temperament resulting in an increase or decrease in reactivity was also used to measure meat quality. The traits used to define carcass and meat quality included carcass bruises (BRU), hot carcass weight (HCW, kg), ribeye area (REA, cm2), backfat thickness (BFT, cm), marbling score (MS), meat pH after thawing (pH), presence or absence of dark cutters, color parameters of luminosity (L*), redness (a*) and yellowness (b*), cooking loss (CL, %), and Warner-Bratzler shear force (WBSF, kg). A principal component (PC) analysis was initially applied to the carcass and meat quality traits, followed by logistic regression models and linear mixed models to evaluate the effects of temperament on carcass and meat quality. The risks of carcass bruises and dark cutters did not differ as a function of any temperament trait (P > 0.05). In turn, animals classified as high MOVb (reactive) had lower PC3 values (P = 0.05), CL (P = 0.02), and tended to have lower MS (P = 0.08). In addition, animals classified as high FSb (faster and reactive cattle) produced carcasses with smaller REA (P < 0.01), higher meat pH (P < 0.01), lower color gradients (L*, P = 0.04; b*, P < 0.01), and lower PC1 and PC4 scores (P < 0.01) when compared with the low FSb class. For preslaughter temperament, high MOVps was related to lower color a* (P = 0.04), whereas high FSps was related to lower HCW, MS, and PC2 (P < 0.01) than the calmer ones (low FSps). The reduction in MOV was related to more tender meat, and the reduction in FS to heavier carcass and brighter meat. We conclude that excitable temperament in Nellore cattle may have negative effects in some of the carcass and meat quality attributes assessed, mainly those related to muscle deposition on carcass and color gradients. Measurement of temperament before the cattle entered the feedlot was a better predictor of carcass and meat quality traits, compared with temperament assessment at the end of the feeding period.

Flight speed as an indicator of Zebu cattle growth performance and suitability to the feedlot environment

Context Studies assessing the relationship between cattle reactivity and growth performance, as well as suitability to the feedlot, in Zebu cattle are limited. Based on previous studies using Bos Taurus cattle, it is expected that reactivity measured at weaning could be used as a predictor of feedlot performance, and that cattle with greater flight speed (FS) would have reduced average daily gain (ADG). Aims The aims of this study were to (1) determine if FS (m/s) measured before entry into the feedlot could be used as a predictor of cattle performance, (2) evaluate the consistency of FS over time, and (3) determine when FS should be measured to best predict animal suitability to the feedlot. Methods A total of 54 Nellore and 40 Guzerat calves were assessed by using FS, which was collected at the time of (FS0) and 1 week after weaning (FS1), as well as on Day 28 (FS28), 56 (FS56) and 168 (FS168) after entry into the feedlot, and a FS average was calculated using FS28, FS56 and FS168 (FS28–168). Performance using ADG (kg/calf.day) was calculated for each animal over three periods: ADG1–28, ADG28–168 and ADG1–168. Bunk attendance (min/calf.day) was recorded over a 173-day feeding period. Key results The ADG28–168 was reduced by 0.14 kg/calf.day for each unit increase in FS0 (P &lt; 0.05). Both ADG28–168 and ADG1–168 were reduced by 0.02 kg/calf.day for each unit increase in FS1 (P ≤ 0.01), but neither FS0 nor FS1 was associated with ADG1–28 (P &gt; 0.10). A significant increase was observed between FS1 and FS28 (P &lt; 0.01), followed by a reduction in FS56 (P &lt; 0.01) and FS168 (P &lt; 0.01). Conclusion FS measured at or within 1 week of weaning has the potential to be used as an indicator of feedlot growth performance in Nellore and Guzerat cattle. Implications Although our results do not indicate the efficacy of FS as a predictor of early suitability of cattle to the feedlot, it does have the potential to support its recommendation as an indicator of overall feedlot growth performance in Nellore and Guzerat breeds.

Effects of temperament at feedlot arrival and breed type on growth efficiency, feeding behavior, and carcass value in finishing heifers

Objectives were to evaluate the effects of temperament at feedlot arrival and breed type on productivity, feed efficiency, feeding behavior, and carcass quality traits in finishing beef heifers, and to examine interactions between temperament and breed type. Heifers (Angus, Braford, Brangus, and Simbrah, N = 411, BW = 280 kg) were fed a high-grain diet (ME = 3.0 Mcal/kg DM) in pens equipped with electronic feed bunks. Quality grade (QG), yield grade (YG), and Warner-Bratzler shear (WBS) force values (day 1 and 14 postmortem) were evaluated. Relative exit velocity (REV) at feedlot arrival was used as a covariate in mixed models to assess the effects of temperament and interactions with breed type, with means compared at ±1 SD from the mean initial REV. Calm heifers (mean REV minus 1 SD) had 4% greater (P < 0.001) initial BW, 12% greater (P < 0.001) ADG, 8% greater (P < 0.001) DMI, and 4% greater (P < 0.02) G:F than heifers with excitable temperaments (mean REV plus 1 SD). A temperament × breed interaction was detected (P < 0.01) for residual feed intake (RFI). Braford heifers had a more (P < 0.05) negative REV covariate slope (-1.49 ± 0.65) than the other breeds, such that excitable Braford heifers had lower (P < 0.05) RFI than the other breeds with excitable temperaments. Temperament × breed interactions were observed (P < 0.001) for DMI per BW0.75 and bunk visit (BV) duration. Braford heifers had more (P < 0.05) negative REV covariate slopes for both traits than Angus, Brangus, and Simbrah heifers such that excitable Braford heifers consumed less (P < 0.05) DMI per BW0.75 and had less BV duration compared to excitable Angus and Brangus heifers. Calm heifers had 9% greater (P < 0.01) meal duration, and consumed meals that were 22% longer (P < 0.001) and 17% larger (P < 0.001) compared to excitable heifers. Calm heifers had 12% more (P < 0.001) BV events per meal then excitable heifers. Carcasses from calm heifers were 4% heavier (P < 0.05) and had 7% greater (P = 0.05) backfat (BF) depth and tended to have 4% greater (P = 0.07) USDA YG than carcasses from excitable heifers. Additionally, loin steaks from calm heifers had 8% lower (P < 0.05) WBS force than steaks from excitable heifers. Based on a carcass grid with discounts and premiums for HCW, QG, YG, and tenderness, calm heifers returned $62 more (P < 0.01) revenue per animal than excitable heifers. These results demonstrate that heifers with divergent phenotypes for temperament on feedlot arrival differ in their performance, feed efficiency, and feeding behavior patterns, as well as carcass quality and revenue.

Systems Biology Reveals NR2F6 and TGFB1 as Key Regulators of Feed Efficiency in Beef Cattle

Systems biology approaches are used as strategy to uncover tissue-specific perturbations and regulatory genes related to complex phenotypes. We applied this approach to study feed efficiency (FE) in beef cattle, an important trait both economically and environmentally. Poly-A selected RNA of five tissues (adrenal gland, hypothalamus, liver, skeletal muscle and pituitary) of eighteen young bulls, selected for high and low FE, were sequenced (Illumina HiSeq 2500, 100 bp, pared-end). From the 17,354 expressed genes considering all tissues, 1,335 were prioritized by five selection categories (differentially expressed, harboring SNPs associated with FE, tissue-specific, secreted in plasma and key regulators) and used for network construction. NR2F6 and TGFB1 were identified and validated by motif discovery as key regulators of hepatic inflammatory response and muscle tissue development, respectively, two biological processes demonstrated to be associated with FE. Moreover, we indicated potential biomarkers of FE, which are related to hormonal control of metabolism and sexual maturity. By using robust methodologies and validation strategies, we confirmed the main biological processes related to FE in Bos indicus and indicated candidate genes as regulators or biomarkers of superior animals.

Harvest Method Influences Color Stability of Longissimus Lumborum Steaks from Bos indicus Cattle

Brazil is a major beef exporter to countries where religious slaughter without stunning is mandatory. Fresh beef color influences consumers’ purchase decisions, and harvest method influences beef quality attributes, such as color, water holding capacity, pH, and lipid oxidation. Beef color is a breed-specific trait, and the excitable temperament of Bos indicus cattle can affect fresh meat color. Nonetheless, the effects of harvest method on color and oxidative stabilities of beef from Bos indicus cattle have not been investigated yet. Therefore, our objective was to evaluate the impact of harvest method on color and oxidative stabilities of longissimus lumborum (LL) steaks from Bos indicus beef cattle. The LL muscles (24 h post-mortem) were obtained from 12 Nellore bull carcasses, harvested by either captive bolt stunning (CBP; n = 6) or without stunning (NST; n = 6). The muscles were fabricated into 2.54-cm steaks, aerobically packaged, and stored for 9 d at 4°C in darkness. Myoglobin concentration was analyzed on d 0, whereas pH, instrumental color, lipid oxidation, and water holding capacity were evaluated on d 0, 3, 6, and 9. While CBP and NST steaks exhibited similar (P > 0.05) myoglobin concentration (4.84 mg/g in CBP; 4.84 mg/g in NST), CBP steaks exhibited greater (P < 0.05) surface redness and color stability than their NST counterparts throughout the storage. On the other hand, NST steaks exhibited greater (P < 0.05) pH, yellowness, and water holding capacity than CBP steaks. Overall, the lightness and lipid oxidation were greater (P < 0.05) in NST steaks than their CBP counterparts. These results indicated that harvest method influences surface discoloration and oxidative stability of fresh LL steaks from Bos indicus cattle.

Performance, carcass and meat quality traits of grazing cattle with different exit velocity

To evaluate the effect of grazing cattle temperament on performance, as well as carcass and meat quality traits, exit velocity (EV) was assessed throughout two production cycles (PC1, n = 38 and PC2, n = 52). Individual EV determinations were assessed throughout each PC and then 100-days period averages were calculated for each animal. Animals were ranked based on their EV (EV-RANK) in the first 100-days period as SLOW, FAST and MEDIUM. The EV decreased from weaning to slaughter in FAST and MEDIUM (P &lt; 0.05); but did not change in SLOW (P &gt; 0.10). Initial liveweight was lowest in FAST and highest in MEDIUM (P = 0.03). DM intake (P = 0.08) and average daily gain (P = 0.94) were not affected by EV-RANK, but carcass subcutaneous fat thickness was lowest in FAST and highest in MEDIUM (P = 0.02). Longissimus muscle colour and shear-force were not affected by EV-RANK (P &gt; 0.05), but muscle glycogen content at slaughter was higher in MEDIUM than in SLOW or FAST (P = 0.047). No EV-RANK effects were observed in the present study on meat colour and shear-force. However, its effects on subcutaneous fat thickness and muscle glycogen could result in low meat quality of temperamental cattle under more stressful handling situations.

Prediction of meat quality traits in Nelore cattle by near-infrared reflectance spectroscopy

The main definition for meat quality should include factors that affect consumer appreciation of the product. Physical laboratory analyses are necessary to identify factors that affect meat quality and specific equipment is used for this purpose, which is expensive and destructive, and the analyses are usually time consuming. An alternative method to performing several beef analyses is near-infrared reflectance spectroscopy (NIRS), which permits to reduce costs and to obtain faster, simpler, and nondestructive measurements. The objective of this study was to evaluate the feasibility of NIRS to predict shear force [Warner-Bratzler shear force (WBSF)], marbling, and color (*a = redness; b* = yellowness; and L* = lightness) in meat samples of uncastrated male Nelore cattle, that were approximately 2-yr-old. Samples of longissimus thoracis (n = 644) were collected and spectra were obtained prior to meat quality analysis. Multivariate calibration was performed by partial least squares regression. Several preprocessing techniques were evaluated alone and in combination: raw data, reduction of spectral range, multiplicative scatter correction, and 1st derivative. Accuracies of the calibration models were evaluated using the root mean square error of calibration (RMSEC), root mean square error of prediction (RMSEP), coefficient of determination in the calibration (R2C), and prediction (R2P) groups. Among the different preprocessing techniques, the reduction of spectral range provided the best prediction accuracy for all traits. The NIRS showed a better performance to predict WBSF (RMSEP = 1.42 kg, R2P = 0.40) and b* color (RMSEP = 1.21, R2P = 0.44), while its ability to accurately predict L* (RMSEP = 1.98, R2P = 0.16) and a* (RMSEP = 1.42, R2P = 0.17) was limited. NIRS was unsuitable to predict subjective meat quality traits such as marbling in Nelore cattle.

Effects of temperament on growth, plasma cortisol concentrations and puberty attainment in Nelore beef heifers

Excitable temperament disrupts physiological events required for reproductive development in cattle, but no research has investigated the impacts of temperament on growth and puberty attainment in Bos indicus females. Hence, this experiment evaluated the effects of temperament on growth, plasma cortisol concentrations and puberty attainment in B. indicus heifers. A total of 170 Nelore heifers, weaned 4 months before the beginning of this experiment (days 0 to 91), were managed in two groups of 82 and 88 heifers each (mean ± SE; initial BW=238±2 kg, initial age=369±1 days across groups). Heifer temperament was evaluated via exit velocity on day 0. Individual exit score was calculated within each group by dividing exit velocity into quintiles and assigning heifers with a score from 1 to 5 (1=slowest; 5=fastest heifer). Heifers were classified according to exit score as adequate (ADQ, n=96; exit score⩽3) or excitable temperament (EXC, n=74; exit score&gt;3). Heifer BW, body condition score (BCS) and blood samples were obtained on days 0, 31, 60 and 91. Heifer exit velocity and score were recorded again on days 31, 60 and 91. Ovarian transrectal ultrasonography was performed on days 0 and 10, 31 and 41, 60 and 70, 81 and 91 for puberty evaluation. Heifer was declared pubertal at the first 10-day interval in which a corpus luteum was detected. Exit velocity and exit score obtained on day 0 were correlated (r⩾0.64, P&lt;0.01) with evaluations on days 31, 60 and 91. During the experiment, ADQ had greater (P&lt;0.01) mean BCS and BW gain, and less (P&lt;0.01) mean plasma cortisol concentration compared with EXC heifers. Temperament × time interactions were detected (P&lt;0.01) for exit velocity and exit score, which were always greater (P&lt;0.01) in EXC v. ADQ heifers. A temperament × time interaction was also detected (P=0.03) for puberty attainment, which was delayed in EXC v. ADQ heifers. At the end of the experiment, a greater (P&lt;0.01) proportion of ADQ were pubertal compared with EXC heifers. In summary, B. indicus heifers classified as EXC had reduced growth, increased plasma cortisol concentrations and hindered puberty attainment compared to ADQ heifers. Moreover, exit velocity may serve as temperament selection criteria to optimize development of B. indicus replacement heifers.

Pre-slaughter cattle welfare indicators for use in commercial abattoirs with voluntary monitoring systems: A systematic review

Animal welfare has become an important subject of public, economic and political concern, leading to the need to validate indicators that are feasible to use at abattoirs. A systematic review was carried out, which identified 72 cattle welfare indicators (CWI) that were classified into four categories (physiological, morphometric, behavioral and meat quality). Their validity and feasibility for use in abattoirs were evaluated as potential measures of cattle welfare during transportation to the abattoir and at the abattoir itself. Several highly valid indicators were identified that are useful to assess welfare at abattoirs, including body condition score, human-animal interactions, vocalizations, falling, carcass bruising, and meat pH. In addition, some intermediate valid indicators are useful and should be investigated further. Information along the food chain could be used systematically to provide a basis for a more-risk-based meat inspection. An integrated system based on the use of key indicators defined for each inspection step with the setting of alarm thresholds could be implemented.

Divergent temperaments are associated with beef tenderness and the inhibitory activity of calpastatin

Ninety-six feedlot-finished Nellore steers were used to verify the relationship between temperament indicators and meat tenderization. Temperament index (TI), chute score (CS), and average of exit velocity (EV) with CS (AT) presented low positive correlations (P≤0.05) with shear force, either at 2 or 16days postmortem (WBSF-16). The rectal temperature was consistently correlated with temperament indicators (TI, CS, and AT) and WBSF-16. Two groups (n=12) representing the most tender (39.2±4.9N) and most tough meat (94.1±11.8N), based on WBSF-16, were compared for temperament, and calpastatin activity (CASTa) was determined 48h postmortem. The tender group presented lower EV, TI, and AT (P≤0.05). The tender group exhibited lower (P≤0.05) CASTa in the triceps brachii muscle, but there was no difference in CASTa in the longissimus lumborum muscle between WBSF groups. Meat tenderness and inhibitory activity of calpastatin may be associated with divergent temperament indices in zebu cattle.

Effects of temperament on physiological, productive, and reproductive responses in beef cows

This experiment evaluated the effects of temperament on physiological, productive, and reproductive responses in beef cows. A total of 953 lactating, multiparous, non-pregnant Nelore cows (age = 99 ± 2 mo; days post-partum = 51.4 ± 0.3 d; BCS = 5.34 ± 0.04; BW = 430 ± 2 kg) were allocated into 8 groups of approximately 120 cows each. Groups were assigned to an estrus synchronization + timed-AI protocol at the beginning of the breeding season. Concurrently with AI, blood samples were collected, hair samples were clipped from the tail switch, and cow temperament was evaluated via chute score and exit velocity. Individual exit score was calculated within each group by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest; 5 = fastest cow). Temperament scores were calculated by averaging cow chute score and exit score, and used to define cow temperament ( ≤ 3 = adequate, = 726; ADQ; > 3 = excitable, = 227; EXC). Cows not pregnant to AI were assigned to a second timed-AI protocol ( = 184 ADQ and 72 EXC) or exposed ( = 269 ADQ and 90 EXC) to bulls for 60 d. Pregnancy status was verified 30 d after each AI and 45 d after the breeding season via transrectal ultrasound. Cow age, BW, BCS, and d post-partum at the beginning of the breeding season were similar ( ≥ 0.27) between ADQ and EXC cows. At first timed-AI, EXC had greater ( < 0.01) serum cortisol but similar ( ≥ 0.87) serum haptoglobin and hair cortisol concentrations compared with ADQ cows (49.1 vs. 39.1 ng/mL of serum cortisol, SEM = 1.0). Pregnancy rate to first timed-AI tended ( = 0.09) to be less in EXC vs. ADQ cows (41.0 vs. 47.3%; SEM = 3.6), whereas no treatment differences were detected ( ≥ 0.23) for subsequent pregnancy outcomes. Calving rate was less ( = 0.04) in EXC vs. ADQ cows (68.3 vs. 74.8%; SEM = 2.2), which can be attributed to the greater ( = 0.05) pregnancy loss detected in EXC cows (9.9 vs. 5.9%; SEM = 1.4). Weaning rate tended ( = 0.09) to be less, whereas calf weaning BW and age were less ( ≤ 0.05) in EXC vs. ADQ cows (63.9 vs. 69.4%, SEM = 2.4; 209 vs. 212 d, SEM = 1; 204 vs. 210 kg, SEM = 2). Hence, kg of calf weaned/cow exposed to breeding was reduced ( = 0.04) in EXC vs. ADQ cows (130 vs. 146 kg, SEM = 5). In summary, cows with excitable temperament had reduced reproductive performance and overall productivity compared to cohorts with adequate temperament when exposed to timed-AI + natural breeding.