Associations between endotoxin-induced metabolic changes and temperament in Brahman bulls,

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.

Sexual Dimorphic Innate Immune Response to a Viral-Bacterial Respiratory Disease Challenge in Beef Calves

The potential for sexually dimorphic innate immune responses to respiratory disease was evaluated, where eight steers and seven heifers (280 ± 4 kg) were subjected to a viral−bacterial respiratory disease challenge utilizing bovine herpesvirus-1 (BoHV-1; intranasal; 1 × 108 PFU/nostril) and Mannheimia haemolytica (MH; intratracheal; 1.3 × 107 CFU/head) administered 72 h later. Body temperature was lesser in heifers than steers (p < 0.01). There was a sex × time interaction (p = 0.05) for white blood cells where heifers had reduced concentrations compared with steers at −72 and 0 h but greater concentrations from 36 to 60 h post-MH. Concentrations of neutrophils were lesser in heifers compared to steers from 0 to 4 h, and from 8 to 12 h (p = 0.03). Lymphocytes were greater in heifers compared to steers at 12 h and from 36 to 60 h post-MH (p < 0.01). The neutrophil−lymphocyte ratio was lesser in heifers compared to steers from 2 to 24 h and at 48 h post-MH (p < 0.01). Monocytes were greater in heifers compared to steers from 24 to 60 h post-MH (p < 0.01), while eosinophils were greater in heifers compared to steers at 48 and 60 h (p < 0.01). Serum IL-4 was lesser in heifers compared to steers at 0 h and from 2 to 72 h post-MH challenge (p = 0.02). Non-esterified fatty acid concentrations were lesser (p < 0.01) in heifers compared to steers from 2 to 4 h post-MH challenge. Urea nitrogen concentrations were greater (p < 0.01) in heifers than steers at 36 h post-MH challenge. Data from this study reveal distinct differences in the acute phase response following a respiratory disease challenge where steers produced an early response, while the response in heifers appeared to be delayed.

Habituation Protocols Improve Behavioral and Physiological Responses of Beef Cattle Exposed to Students in an Animal Handling Class

Simple Summary

Students in agricultural programs have the opportunity to interact with animals during different teaching activities. However, students’ interactions with livestock may be distressing to the animals and can affect the students’ and animals’ safety. We investigate whether two human-animal habituation strategies, one with positive tactile stimulation and one without, would improve behavioral and physiological responses of beef heifers during a livestock handling class. Overall, heifers that received a habituation treatment had more positive behavior responses, and decreased physiological stress responses in comparison to heifers that were not exposed to habituation. Furthermore, the heifers exposed to the habituation with a positive tactile stimulation had the greatest improvements in behavior in comparison to control and non-stimulated heifers, exhibiting more positive behaviors when interacting with humans. Strategies to habituate cattle to human interaction with positive stimulation aligned with training humans that handle and interact with cattle on best practices and cattle behavior can improve behavior, reduce stress-related physiological responses and enhance safety for both humans and animals.

Abstract

Our objective was to determine the impact of different habituation protocols on beef cattle behavior, physiology, and temperament in response to human handling. Beef heifers were exposed to three habituation strategies: (1) tactile stimulation (brushing) in the working chute for seven consecutive days (STI; n = 18); (2) passage through the working chute for seven consecutive days (CHU; n = 19) and; (3) no habituation (CON; n = 19). Individual heifer respiratory rate (RR; n/min), internal vaginal temperature (VAGT; °C), and blood cortisol were measured. Further, behavior parameters were observed to generate a behavior score, and heifer interaction with students and their behavioral responses were recorded. Habituation with STI and CHU resulted in improved numerical behavioral scores compared to CON, and greater (p ≤ 0.05) handling latencies. Vaginal temperature was decreased in STI compared to CHU and CONT (p ≤ 0.05). Cortisol concentration did not differ among treatments, but decreased (p ≤ 0.05) from the start of the experiment to 14 days after treatment initiation. Both habituation protocols showed benefits, but heifers that received the positive tactile stimulation in the chute had the greatest behavior improvements. Furthermore, these heifers responded more calmly during student-animal interactions in class, which is beneficial for the students’ and animals’ safety.

Prenatal immune stimulation alters the postnatal acute phase and metabolic responses to an endotoxin challenge in weaned beef heifers. Transl Anim Sci 2021;5:txab097. [PMID: 34250451 DOI: 10.1093/tas/txab097]

This study evaluated whether administration of lipopolysaccharide (LPS) at each trimester of gestation would alter the acute phase (APR) and metabolic responses to a postnatal LPS challenge in weaned heifers. Pregnant crossbred multiparous cows (n = 50) were randomized into prenatal immune stimulation (PIS; n = 24; administered 0.1 µg/kg BW LPS subcutaneously at 71 ± 2, 170 ± 2 and 234 ± 2 d of gestation) and saline (CON; n = 26) groups. From these treatment groups, heifer calves (n = 12 PIS and 11 CON) were identified at weaning (244 ± 3 d of age) to receive an LPS challenge. On d 0, heifers were fitted with vaginal temperature (VT) devices, jugular catheters, and moved into individual stalls. On d 1, heifers were challenged i.v. with LPS (0.5 µg/kg BW) at 0 h. Blood samples were collected and sickness behavior scores (SBS) recorded at 0.5 h intervals from -2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for cortisol, cytokines, glucose, non-esterified fatty acids (NEFA), and serum urea nitrogen (SUN) concentrations. Baseline VT was lesser in PIS heifers from -11 to -5 h pre-LPS (treatment × time: P < 0.01) compared to the CON; however, the post-LPS VT response did not differ between treatments (P = 0.89). There was a treatment × time interaction (P < 0.01) for SBS with PIS heifers having lesser SBS from 0.5 to 2 h post-LPS compared to CON. There was a treatment × time interaction (P = 0.03) for cortisol with PIS heifers having greater cortisol at 0.5, 3, 3.5, 5.5 and 6.5 h post-LPS compared to CON. There were treatment × time interactions for the post-LPS cytokine responses (P ≤ 0.05). Specifically, PIS heifers had greater TNF-α from 1.5 to 2 h, yet less TNF-α at 3 h than CON (P < 0.01), and PIS heifers had greater IFN-γ from 3.5 to 5.5 h post-LPS than CON (P < 0.01). In contrast, IL-6 was less in PIS than CON heifers from 1.5 to 8 h post-LPS (P < 0.001). Glucose concentrations were greater in PIS heifers at -1 h, but less at 2, 3 and 5.5 h compared to CON (treatment × time: P < 0.01). Serum NEFA concentrations were greater (P = 0.04) in PIS than CON heifers. There was a treatment × time interaction (P < 0.01) for SUN with PIS heifers having greater SUN concentrations at -2, -1.5, 2, 3, 6.5 and 24 h than CON. These data demonstrate that in utero exposure to multiple low doses of endotoxin has lasting physiological and immunological effects when the offspring encounter a similar postnatal immunological insult.

Supplementation of OmniGen-AF improves the metabolic response to a glucose tolerance test in beef heifers. Transl Anim Sci 2020;3:1521-1529. [PMID: 32704915 DOI: 10.1093/tas/txz130]

This study determined whether feeding the immunomodulating supplement, OmniGen-AF, to feedlot heifers would alter metabolic profiles to a glucose tolerance test. Heifer calves (n = 32; 217 ± 2 kg) were allocated into two treatment diets: 1) Control, fed a standard receiving ration, and 2) OmniGen, fed the Control diet supplemented with OmniGen at 4.54 g/45 kg BW/d. Heifers were fed for 42 d. On d 42, Heifers were processed through a working facility for placement of indwelling jugular catheters. After these procedures, heifers were moved into individual stanchions in an enclosed barn and all heifers were fed their treatment diets at 1400 h. All orts were removed at 2000 h to allow for a 12-h fast prior to first blood collection. The following day, heifers were administered 0.5 mL/kg BW of a 50% dextrose solution at 0900 h (0 min). Blood samples were collected for serum isolation at -60, -45, -30, -15, 0, 10, 20, 30, 45, 60, 90, 120, and 150 min relative to bolus dextrose infusion. Serum was stored at -80 ^oC until analyzed for cortisol, glucose, insulin, non-esterified fatty acid (NEFA) and urea N concentrations. There was a treatment × time interaction for post-challenge cortisol (P = 0.004) such that cortisol was greater in OmniGen heifers than Control heifers from 10- to 45- min post-infusion. Glucose concentrations increased post-infusion (P < 0.01) and were reduced in OmniGen compared to Control heifers at 10-, 45-, and 90-min after challenge (treatment × time P < 0.001). Similarly, there was a treatment × time interaction for post-challenge insulin concentrations (P = 0.04) such that insulin was greater in OmniGen-fed heifers than Control heifers from 10 to 30 min. In addition, there was a treatment × time interaction (P = 0.01) for NEFA concentrations such that concentrations were reduced in OmniGen-supplemented heifers from 10 to 30 min following administration of the dextrose bolus. Serum urea N concentrations were greater in Control heifers at 150 min compared to OmniGen-fed heifers (post-challenge treatment × time interaction: P < 0.001). These data suggest that OmniGen-fed heifers were more responsive to changes in glucose, perhaps affecting the storage and/or redistribution of energy deposits and provide further evidence for altered metabolism in OmniGen-supplemented cattle. The differences observed may explain differences observed in the immune response in OmniGen-supplemented calves.

Modulation of the metabolic response using dexamethasone in beef steers vaccinated with a multivalent respiratory vaccine

Available energy plays a critical role in the initiation and maintenance of an immune response to a pathogen, a process that is further altered by activation of the stress system. This study was designed to determine the effect of an acute vs chronic stress model on the metabolic response to vaccination in naïve beef steers. Steers (n = 32; 209 ± 8 kg) were blocked by body weight (BW) and randomly assigned to one of three treatments: 1) Chronic stress (CHR), 0.5 mg/kg BW dexamethasone (DEX) administered i.v. at 1000 h on day 3 to day 0; 2) Acute stress (ACU), 0.5 mg/kg BW DEX administered i.v. at 1000 h on day 0 only; or 3) Control (CON), no DEX. On day -4, steers were fitted with jugular vein catheters and moved into individual bleeding stalls in an environmentally-controlled facility. Blood samples were collected at -74, -50, and -26 h, at 0.5-h intervals from -4 to 6 h, and at 12, 24, 36, 48, and 72 h relative to vaccination with a combination vaccine (Pyramid 5 + Presponse SQ, Boehringer Ingelheim Animal Health USA, Duluth, GA) at 1200 h on day 0. Data were analyzed by the MIXED procedure of SAS specific for repeated measures. There was a treatment × time interaction (P < 0.001) for serum glucose concentrations. Specifically, glucose concentrations increased at -50 h in CHR steers and at 1200 h in ACU steers and remained elevated through 72 h postvaccination period in these two treatments compared to CON steers. The change in nonesterified fatty acid (NEFA) concentrations relative to baseline values was affected by treatment and time (P < 0.001) such that the change in NEFA was greater in CHR (0.06 ± 0.01 mmol/L), followed by CON (-0.01 ± 0.01 mmol/L) and ACU steers (-0.04 ± 0.01 mmol/L). There was a tendency (P = 0.08) for a treatment × time interaction for change in serum NEFA concentrations. Serum urea nitrogen (SUN) was affected by treatment and time (P < 0.001) such that SUN concentrations were greatest in CHR (12.0 ± 0.1 mg/dL) followed by ACU (10.4 ± 0.1 mg/dL) and CON steers (9.6 ± 0.1 mg/dL); however, the treatment × time interaction was not significant (P = 0.12). These data demonstrate that activation of the stress and immune axes using an acute or chronic stress model can increase energy mobilization prior to and following vaccination in naïve steers, potentially affecting available energy needed to mount an adequate antibody response to vaccination.

Some Negative Effects of Heat Stress in Feedlot Heifers May Be Mitigated via Yeast Probiotic Supplementation

This study was designed to determine if supplementation of a combination live yeast and yeast cell wall product in feed could mitigate the negative impacts associated with heat stress (HS). Crossbred, phenotypically similar beef heifers (n = 32; BW = 385 ± 43 kg) were fed a standard finishing ration without (CON) or with a combination of a live yeast (1.5 g/hd/d) and yeast cell wall product (2.5 g/hd/d; YEAST; Phileo Lesaffre Animal Care, Milwaukee, WI). After 50 d of supplementation, heifers were transported to an environmentally-controlled facility and placed in individual bleeding stalls after indwelling jugular catheters and vaginal temperature (VT) loggers were inserted. Heifers were kept in thermoneutral (TN) conditions for 48 h [temperature-humidity index (THI) ~67; d 1-2] then were subjected to HS for 4 d (peak THI ~80; d 3-6). From d 2-6, hourly blood samples were collected for serum isolation from 1400 to 1800 h and again from 2200 to 0200 h which represented the daily targeted peak and nadir of THIs. A whole blood sample was collected twice daily at 1400 and 2200 h for complete blood counts (CBC). There was no difference in BW (P = 0.14) or ADG (P = 0.53) between the treatments during HS. Yeast-supplemented heifers exhibited reduced VT during HS compared to CON heifers (P < 0.01). There was no difference in water intake during the TN phase (P = 0.25); however, YEAST heifers consumed more water/h (P < 0.01) and had increased drinking bouts (P < 0.01) during HS compared to CON heifers. Respiration rates (RR) did not differ (P = 0.21) during TN, but YEAST heifers tended (P = 0.09) to have decreased RR during HS compared to CON heifers. There were no differences between treatments when evaluating CBC parameters (P ≥ 0.10). There was a tendency (P = 0.08) for greater cortisol in the CON than YEAST heifers during HS; however, glucose (P = 0.38) and NEFA (P = 0.70) concentrations did not differ. In summary, supplementation of live yeast and yeast cell wall products to feedlot heifers may mitigate some of the negative effects associated with HS in feedlot cattle as observed in decreased RR and VT and increased water intake.

A bioactive extract from Olea europaea protects newly weaned beef heifers against experimentally induced chronic inflammation1

Weaning is one of the most stressful periods in the life of a ruminant. Several factors entrenched within typical management practices pose challenges to the calf gastrointestinal health. Weaning is associated with losses in BW and feed intake. In addition, increasing highly fermentable carbohydrates in the diet at the expense of physically effective fiber after weaning predisposes the development of rumen acidosis and increases the concentration of endotoxin in rumen fluid and the permeability of the lower gut to luminal contents. Endotoxin translocation can elicit immune activation, shifting the metabolic priorities toward the immune system, which if sustained over time can hinder animal health and performance. Strategic supplementation of additives with anti-inflammatory capacity could represent a suitable approach to decrease systemic inflammation, restoring barrier function to luminal contents. Bioactive extracts from Olea europaea have anti-inflammatory activity and have been shown to reduce systemic inflammation in other animal models. A generalized randomized block design was used to evaluate the impact of feeding an olive oil bioactive extract (OBE) to newly weaned heifers injected intravenously with sequentially increasing doses of lipopolysaccharide (LPS). A total of 36 heifers, distributed across 3 experimental periods, were randomly assigned to 1 of 4 treatments that consisted of intravenous injection of either saline (CTL-) or with 6 sequentially increasing doses of LPS (0.10, 0.25, 0.50, 0.75, 1.00, and 1.25 µg/kg of BW) over a 10-d period (CTL+), and CTL+ plus dietary supplementation with a low (OBE-L; 0.04% of diet DM) or a high (OBE-H; 0.16% of diet DM) dose of OBE. Feeding OBE reduced some of the negative effects of prolonged immune activation with LPS, such as improved DMI and decreased intravaginal temperature in some, but not all of the days of LPS challenge (P < 0.05). In addition, feeding OBE reduced circulating concentration of inflammatory markers such as IL-6 and haptoglobin (P < 0.05). Heifers supplemented with OBE had reduced cell surface expression of the cluster of differentiation 14 (CD14) in monocyte cells (P < 0.01), a key receptor for LPS recognition, which was correlated with a faster recovery of immune cell counts in plasma. In conclusion, dietary supplementation with OBE was successful in mitigating the negative effects of sustained immune activation in newly weaned heifers.

Changes in the Hematological Variables in Pigs Supplemented With Yeast Cell Wall in Response to a Salmonella Challenge in Weaned Pigs

Stressors experienced by pigs at weaning may negatively impact health and productivity. Thus, supplements that enhance pig immunity during the early post-weaned period are of great interest to the swine industry. The objective of this experiment was to evaluate the performance and hematological responses of weaned pigs supplemented with yeast cell wall (YCW) when challenged orally with Salmonella Typhimurium. Weaned pigs were assigned to one of three treatments for 22d (n = 13/treatment): Control diet, which was a non-medicated starter diet (Control); Control diet supplemented with YCW at 250 mg/kg BW (YCW250; Phileo Lesaffre Animal Care, Milwaukee, Wisconsin, USA); and Control diet supplemented with YCW at 500 mg/kg BW (YCW500). On d19 blood samples were collected from -6 to 72 h relative to oral Salmonella Typhimurium (1 × 106 cfu/pig) challenge. Gain:feed was greater (P = 0.01) in YCW250 treatment compared to both Control and YCW500 pigs. Baseline intraperitoneal temperature was greater (P < 0.001) in YCW250 pigs than Control or YCW500 pigs. There was a treatment x time interaction for the change in intraperitoneal temperature (P < 0.01), post-challenge cortisol, white blood cell counts (WBC), neutrophils, and neutrophil:lymphocyte ratio (P ≤ 0.03). Control pigs had greater (P < 0.05) cortisol concentrations than both YCW-supplemented groups at 0 h, but Control pigs had reduced (P < 0.05) cortisol compared to YCW500 pigs at 24 and 30 h post-challenge. Control pigs had greater (P < 0.05) WBC counts than both YCW-supplemented groups 6 and 12 h post-challenge, and YCW250 pigs had reduced (P < 0.01) WBC counts than Control and YCW500 pigs 18 h post-challenge. Neutrophil counts were greater (P < 0.05) in Control pigs than both YCW-supplemented groups at 6 and 12 h post-challenge and were greater (P = 0.02) than YCW250 pigs at 18 h post-challenge. Lymphocytes were greater (P < 0.001) in Control and YCW500 pigs pre- and post-challenge compared to YCW250 pigs. Control pigs had the greatest (P < 0.001) monocyte counts compared to YCW treatments. There was no effect of yeast supplementation on fecal shedding or Salmonella counts in the rectum, colon or cecum (P ≥ 0.05). While some differences were observed in intraperitoneal temperature and some hematological variables, data suggests there were minimal effects of yeast supplementation on the acute immune response to Salmonella challenge.

The course of plasma cortisol concentration after three different doses of ketamine in xylazine-premedicated calves

OBJECTIVE

To investigate the influence of ketamine on plasma cortisol concentration (PCC) in calves.

STUDY DESIGN

Prospective, randomized experimental study.

ANIMALS

A total of 41 healthy, predominantly cross-bred calves, aged 3-4 months.

METHODS

Calves were premedicated with intramuscular xylazine (0.2 mg kg^-1) and randomly divided into four groups. The control group (CONT) received saline (after 10, 20 and 30 minutes), whereas groups K1, K2 and K3 were injected intravenously once, twice or thrice, respectively, with 4 mg kg^-1 of ketamine at 10 minute intervals. Blood samples were collected at fixed time points and analysed to determine the PCC; furthermore, the plasma concentrations of ketamine and norketamine were assessed after a single ketamine administration in group K1. The pharmacokinetic parameters of ketamine and norketamine were calculated as plasma concentrations versus time.

RESULTS

All groups showed significant (p < 0.0001) increases in PCC compared with the baseline value; however, for the first 60 minutes, PCC was significantly higher in the ketamine-treated groups (time × dose effect; K1: p < 0.0001; K2: p = 0.0008; K3: p = 0.0135) than in the CONT group. The group receiving triple ketamine administration exhibited the greatest increase in PCC compared with the baseline level (121.17 ± 33.25 nmol L^-1), whereas in the CONT group, the increase in PCC was smaller than the baseline cortisol level (82.67 ± 36.86 nmol L^-1). The plasma concentration of ketamine decreased with a half-life of approximately 12 minutes, which was longer than the dose interval. The increase in PCC after triplicate administration might, therefore, have resulted from ketamine/norketamine accumulation rather than from the total dosage.

CONCLUSIONS AND CLINICAL RELEVANCE

Our results showed that ketamine increases the plasma concentration of cortisol in xylazine-treated calves. Thus, the previous treatment of subjects needs to be considered in studies using plasma/serum cortisol concentrations as an indicator of pain.

Exposure to lipopolysaccharide in utero alters the postnatal metabolic response in heifers

This study was designed to determine the effect of prenatal lipopolysaccharide (LPS) exposure on the postnatal metabolic response to an LPS challenge in beef heifers. Pregnant, crossbred cows ( = 50) were assigned to a prenatal immune stimulation (PIS; = 25; administered 0.1 µg/kg BW LPS subcutaneously 233 ± 15d of gestation) or saline treatment group (Control; = 25). Birth and weaning BW of calves were collected. There was not (> 0.05) a treatment × gender interaction for birth weight or 205-d adjusted weaning BW. Treatment did not affect (> 0.05) birth BW, but steers and heifers of PIS cows had greater ( < 0.02) 205-d adjusted weaning BW than offspring from Control cows. From the 2 prenatal treatment groups, heifer calves ( = 12 PIS, 11 Control) were identified at weaning (238 ± 15 d of age) to subsequently receive an LPS challenge. On d 0, heifers were fitted with indwelling jugular catheters and were moved into individual pens. On d 1, heifers (fed at 0600 h) were challenged i.v. with LPS (0.5 µg/kg BW) at 0 h (1000 h). Blood samples were collected at 30-min intervals from -2 to 8 h and again at 24 h relative to the LPS challenge. There was a treatment × time interaction ( < 0.01) for cortisol; PIS heifers had greater cortisol from 4 to 6.5 h post-LPS challenge ( < 0.001). There was a treatment × time interaction ( = 0.04) for serum glucose such that glucose was greater ( = 0.01) in PIS than Control heifers at 0.5 h, but was greater in Control than PIS heifers at 2, 4.5, and 7 h post-LPS challenge. This resulted in overall time ( < 0.01) and treatment ( < 0.01) effects such that Control heifers had greater glucose concentrations than PIS heifers. There was a tendency ( = 0.10) for a treatment × time interaction for serum NEFA, such that NEFA was greater in Control than PIS heifers at -2, -1.5, and 7 h relative to the LPS challenge ( ≤ 0.02). Also, there were time ( < 0.01) and treatment effects ( < 0.01) for NEFA with Control heifers having greater NEFA than PIS heifers. Serum BUN was affected by a treatment × time interaction ( < 0.01). Concentrations of BUN were greater in PIS heifers from -1.5 to -1 h, 1 to 2 h, at 4 h, and from 5 to 24 h relative to the LPS challenge. These results demonstrate postnatal growth and the metabolic responses of weaned beef calves can be significantly altered with a single exposure to LPS in utero.

A novel objective chute score interacts with monensin to affect growth of receiving cattle

Growth in cattle may be related to animal temperament via alterations in intake or feed conversion. However, temperament is ill-defined, and different temperament measures may relate differently to production traits or interact with dietary factors in their effects. To examine relationships between diet, temperament, growth, and health, 160 crossbred steers (262 ± 22 kg) were used in a 56-d RCBD experiment with a 2 × 2 × 2 factorial treatment structure with 5 pens/treatment. Steers were pen fed a corn silage-based diet with or without monensin (41.9 g/t DM), ad libitum. Temperament treatments (assigned on d -7) were exit velocity (EV; slow vs. fast) and objective chute score (OCS; low vs. high), a novel temperament measure, representing the CV of weights collected at 5 measures/s for 10 s while an animal's head was restrained in a chute. Both were measured on d -7, 0, 14, 28, 55, and 56. Subjective chute scores (SCS; visual estimates of animal activity obtained simultaneously with OCS measures) were measured on d -7 and d 56. Jugular blood samples from d 28 were analyzed for antibody response to leptospirosis vaccine and NEFA concentrations. No monensin × OCS × EV interactions were detected ( ≥ 0.11). There was a positive correlation between SCS and OCS ( < 0.01; = 0.57). Changes in OCS and EV across the duration of the study differed among treatments (treatment × day, < 0.10) and indicated that initial measures may be better proxies of growth than average measures. There were no interactions between EV and OCS ( ≥ 0.15) for any response variable and no interactions among treatments ( ≥ 0.31), nor main effects of temperament factors ( ≥ 0.12) for DMI (%BW). Monensin decreased DMI ( < 0.01) similarly across all levels of EV and OCS. Gains and G:F responses to monensin depended on OCS ( < 0.10) but not EV ( ≥ 0.80). Gain was reduced ( < 0.10) by monensin with low, but not high, OCS, and G:F was increased ( < 0.10) by monensin on high, but not low, OCS. Gain during the second 4 wk was lesser ( = 0.04) in fast, compared with slow, EV animals. Results provide novel indications that certain temperament measures can interact with dietary manipulation to influence animal performance.

Cattle temperament influences metabolism: metabolic response to glucose tolerance and insulin sensitivity tests in beef steers

Cattle temperament, defined as the reactivity of cattle to humans or novel environments, can greatly influence several physiological systems in the body, including immunity, stress, and most recently discovered, metabolism. Greater circulating concentrations of nonesterified fatty acids (NEFAs) found in temperamental cattle suggest that temperamental cattle are metabolically different than calm cattle. Further, elevated NEFA concentrations have been reported to influence insulin sensitivity. Therefore, the objective of this study was to determine whether cattle temperament would influence the metabolic response to a glucose tolerance test (GTT) and insulin sensitivity test (IST). Angus-cross steers (16 calm and 15 temperamental; 216 ± 6 kg BW) were selected based on temperament score measured at weaning. On day 1, steers were moved into indoor stanchions to allow measurement of individual ad libitum feed intake. On day 6, steers were fitted with indwelling rectal temperature probes and jugular catheters. At 9 AM on day 7, steers received the GTT (0.5-mL/kg BW of a 50% dextrose solution), and at 2 PM on day 7, steers received the IST (2.5 IU bovine insulin/kg BW). Blood samples were collected and serum isolated at -60, -45, -30, -15, 0, 10, 20, 30, 45, 60, 90, 120, and 150 min relative to each challenge. Serum was stored at -80°C until analyzed for cortisol, glucose, NEFA, and blood urea nitrogen concentrations. All variables changed over time (P < 0.01). For the duration of the study, temperamental steers maintained greater (P < 0.01) serum NEFA and less (P ≤ 0.01) serum blood urea nitrogen and insulin sensitivity (calculated using Revised Quantitative Insulin Sensitivity Check Index) compared with calm steers. During the GTT, temperamental steers had greater (P < 0.01) serum glucose, yet decreased (P = 0.03) serum insulin and (P < 0.01) serum insulin: serum glucose compared to calm cattle. During the IST, temperamental steers had greater (P < 0.01) serum insulin and a greater (P < 0.01) serum insulin: serum glucose as compared with calm steers. These data demonstrate that differences exist in the manner in which temperamental steers respond to glucose and insulin, potentially a result of elevated serum NEFA concentrations, which may result in changes in utilization and redistribution of energy in temperamental vs calm cattle.

Physiological and metabolic responses of gestating Brahman cows to repeated transportation

This study characterized physiological responses to repeated transportation (TRANS) of gestating cows of differing temperaments. Cows were classified as Calm (C; = 10), Intermediate (I; = 28), or Temperamental (T; = 10). Based on artificial insemination date and pregnancy confirmation, cows were TRANS for 2 h on d 60 (TRANS1), 80 (TRANS2), 100 (TRANS3), 120 (TRANS4), and 140 (TRANS5) ± 5 d of gestation. Indwelling vaginal temperature (VT) monitoring devices were inserted 24 h before each TRANS with VT recorded from 2 h before TRANS and averaged into 5-min intervals through 30 min after TRANS. Serum samples were collected before loading and on unloading from the trailer to determine concentrations of cortisol, glucose, and nonesterified fatty acids (NEFA). Data were analyzed by repeated measures analysis in SAS. Serum cortisol concentrations were affected by temperament ( < 0.001), with T cows having the greater concentrations of cortisol before each TRANS event. All cows (100%) regardless of temperament exhibited elevations in cortisol following each TRANS event. Peak VT was greater ( < 0.001) at TRANS1 relative to all other TRANS events regardless of cow temperament. During TRANS, the T cows tended ( < 0.09) to have greater peak VT (39.86 ± 0.15°C) compared to C (39.41 ± 0.16°C) and I cows (39.55 ± 0.08°C). Area under the VT curve decreased ( = 0.002) from TRANS1 through TRANS5. Pre-TRANS serum glucose concentration at TRANS1 was greater ( < 0.03) for T (68.13 ± 4.31mg/dL) compared to I (53.42 ± 2.78 mg/dL) and C cows (52.76 ± 4.60 mg/dL). The C and I cows had greater changes in NEFA concentration between pre- and post-transport, and T cows showed the least change ( < 0.001). Cow VT and serum glucose concentration decreased in all temperaments ( < 0.01) with repeated TRANS; however, serum NEFA concentration post-TRANS did not vary ( > 0.10) with repeated TRANS events. Serum glucose concentrations were affected ( < 0.02) by a TRANS event by temperament interaction with T cows taking more TRANS events to decrease their change in glucose concentration compared to C and I cows. These results demonstrate that temperament influences physiological responses to stress in gestating Brahman cows. Although repeated transport in our study is confounded with day of gestation, seasonal changes, and learning from repeated handling and transport, repeated transport is a useful model of repeated stress in studying the effects of temperament.

Twenty-four-hour profiles of metabolic and stress hormones in sheep selected for a calm or nervous temperament

Even in the absence of stressors, temperament is associated with changes in the concentration of stress-responsive hormones and, possibly because of such changes, temperament can affect metabolism. We tested whether, in sheep bred for temperament for 14 generations, "nervous" females have greater concentrations of stress-responsive hormones in the absence of stressors than "calm" females, and whether these differences are associated with changes in the concentrations of metabolic hormones. In resting "calm" (n = 8) and "nervous" (n = 8) sheep, concentrations of cortisol, prolactin, leptin, and insulin were measured in blood plasma sampled via jugular catheter every 20 min for 24 h. The animals were individually penned, habituated to their housing and human handling over 7 wk, and fed before sampling began. Diurnal variation was evident for all hormones, but a 24-h cortisol pattern was detected in only 7 individuals. There was no effect of temperament on any aspect of concentrations of cortisol or prolactin, but "calm" animals had greater concentrations of insulin in the early afternoon than "nervous" animals (14.5 ± 1.1 vs 10.0 ± 1.6 μU/mL; P = 0.038), and a similar tendency was seen for leptin (P = 0.092). We conclude that selection for temperament affects the concentration of metabolic hormones in the absence of stressors, but this effect is independent of stress-responsive hormones.

Temperament type specific metabolite profiles of the prefrontal cortex and serum in cattle

In the past decade the number of studies investigating temperament in farm animals has increased greatly because temperament has been shown not only to affect handling but also reproduction, health and economically important production traits. However, molecular pathways underlying temperament and molecular pathways linking temperament to production traits, health and reproduction have yet to be studied in full detail. Here we report the results of metabolite profiling of the prefrontal cortex and serum of cattle with distinct temperament types that were performed to further explore their molecular divergence in the response to the slaughter procedure and to identify new targets for further research of cattle temperament. By performing an untargeted comprehensive metabolite profiling, 627 and 1097 metabolite features comprising 235 and 328 metabolites could be detected in the prefrontal cortex and serum, respectively. In total, 54 prefrontal cortex and 51 serum metabolite features were indicated to have a high relevance in the classification of temperament types by a sparse partial least square discriminant analysis. A clear discrimination between fearful/neophobic-alert, interested-stressed, subdued/uninterested-calm and outgoing/neophilic-alert temperament types could be observed based on the abundance of the identified relevant prefrontal cortex and serum metabolites. Metabolites with high relevance in the classification of temperament types revealed that the main differences between temperament types in the response to the slaughter procedure were related to the abundance of glycerophospholipids, fatty acyls and sterol lipids. Differences in the abundance of metabolites related to C21 steroid metabolism and oxidative stress indicated that the differences in the metabolite profiles of the four extreme temperament types could be the result of a temperament type specific regulation of molecular pathways that are known to be involved in the stress and fear response.

Exogenous administration of lipids to steers alters aspects of the innate immune response to endotoxin challenge

This study examined the effects of increasing energy availability from both dextrose and lipid treatments on the pro-inflammatory response to LPS in Holstein steers. Steers were randomly assigned to one of three groups: saline at 0.5 ml/kg body weight (Control) or 50% dextrose [0.5 ml/kg body weight (Dextrose) to mimic calm cattle’s response to LPS] administered immediately prior to LPS (0.5 µg/kg body weight at 0 h) or continuous lipid emulsion infusion from −1 to 6 h [Intralipid 20% (Baxter, Deerfield, IL USA); 0.5 ml/kg/hr (Lipid) to mimic temperamental cattle]. Concentrations of non-esterified fatty acids (NEFA) were greater in Lipid compared with Control and Dextrose steers. A greater decrease in the change in rectal temperature, relative to baseline, was observed in response to LPS in Dextrose in comparison to control and Lipid steers. Cortisol was greater in Lipid than Dextrose and Control steers from −0.5 to 0 h, yet decreased from 0.5 to 5.5 h relative to LPS challenge. Concentrations of IL-6 were decreased in Lipid steers compared with Dextrose and Control steers, and were decreased in Dextrose compared with Control steers post-LPS challenge. These data suggest that increasing circulating NEFA using an exogenous Lipid emulsion may modulate the pro-inflammatory response in steers.