Shipping suppresses lymphocyte blastogenic responses in Angus and Brahman X Angus feeder calves

Effects of dietary supplementation of a blend of Saccharomyces cerevisiae, multiple live probiotic bacteria, and their fermentation products on performance, health, and rumen bacterial community of newly weaned beef steers during a 56-d receiving period

We examined the effects of a blend of Saccharomyces cerevisiae, multiple live probiotic bacteria, and their fermentation products on performance, health, and the ruminal bacterial community of newly weaned beef steers during a 56-d receiving period. Forty newly weaned Angus crossbred steers (221 ± 25.6 kg BW; 180 ± 17 d of age) were stratified by body weight (BW) into four pens (10 steers per pen) such that each pen had a similar average BW at the beginning of the experiment. The pens were randomly assigned to receive a corn silage basal diet (CON; n = 20) or the basal diet supplemented with 9 g/steer/d of PRO feed additive (PRO; n = 20). The PRO additive is a blend of S. cerevisiae and the fermentation products of Enterococcus faecium, Bacillus licheniformis, B. subtilis, Lactobacillus animalis, and Propionibacterium freudenreichii. The DMI and water consumed were monitored using the GrowSafe intake nodes and custom flow meters, respectively. BWs were recorded weekly to calculate average daily gain (ADG). Before morning feeding, 10 mL of blood was taken from each steer on days 0-7, and thereafter weekly for analyses of immune cells, plasma glucose, and NEFAs. On day 56, rumen fluid samples (200 mL each) were collected from all the steers for microbiome analysis. Over the 56-d receiving period, the supplemental PRO had no effects on DMI, water intake, or ADG. However, compared to CON, beef steers fed supplemental PRO tended to have greater ADG (P = 0.08) and BW (P = 0.07) during the first 14 d of the study. There was a treatment × day interaction (P ≤ 0.05) for WBC, neutrophils and monocytes over the 56 d such that beef steers fed supplemental PRO had lower blood concentrations on certain days during the first 7 d after weaning, indicating reduced inflammation or stress response. The results of the rumen microbiome analysis revealed that the relative abundance of complex fiber degrading or obligate proton-reducing bacterial genera such as Bacteroides, Ruminococcus gauvreauii group, Desulfovibrio, Syntrophococcus, and Acetitomaculum were greater (P ≤ 0.05) in beef steers fed supplemental PRO compared to CON. This study demonstrated that dietary supplementation of PRO improved the growth performance, reduced stress or inflammatory response during the initial days after weaning, and altered the ruminal bacterial community toward increased relative abundance of bacterial genera associated with improved rumen function.

Current Knowledge on the Transportation by Road of Cattle, including Unweaned Calves

Transport conditions have the potential to alter the physiological responses of animals to the psychological or physical stress of transport. Transportation may introduce multiple physical and psychological stressors to unweaned calves and adult cattle, including noise, overcrowding, food and water deprivation, extreme temperatures, commingling with unfamiliar animals, handling by unfamiliar humans, and being placed in a novel environment upon arrival. Apart from these factors, the type of road and even driving skill may affect the welfare of animals. One of the concerns regarding cattle transport is that the handling and marketing of animals prior to a journey may lengthen the period of feed withdrawal. Furthermore, feed withdrawal can impact animal welfare through hunger and metabolic stress. Transportation is also associated with a decrease in animal performance as well as an increase in the incidence of bovine respiratory disease. It is well established that the transportation of cattle is a stressor that causes a quantifiable response; however, excessive stress during transport resulting in physiological or pathological changes can be reduced with best management practices. The objective of this review was to analyse the available scientific literature pertaining to the transport by road of cattle, including unweaned calves.

Interactions between animal temperament and exposure to endophytic tall fescue: Effects on cell-mediated and humoral immunity in beef heifers

Two experiments (n=12 Angus heifers/experiment) investigated influences of animal temperament, as indicated by exit velocity (EV; determined at weaning) and consumption of toxic endophyte-infected tall fescue seed on peripheral lymphocyte production of interferon-γ. Heifers were selected from calves born on the University of Kentucky’s C. Oran Little Research Center. In experiment 1, calves were randomly selected from 50 heifers within a single calf crop. In experiment 2, calves with the 6 fastest and 6 slowest EV in the subsequent year’s calf crop were selected. In both experiments, heifers were assigned to either high or low EV treatments based on relative ranking, and endophyte treatments (toxic endophyte-infected, E+, or endophyte-free, E-, fescue seed) were balanced by body weight. Rations were restricted to 1.8 x NEm and common diet was top-dressed with fescue seed each morning. Experiment 1 had four phases (pre-endophyte treatment/thermoneutral, increased room temperature, increased room temperature/endophyte treatment, and post-endophyte/thermoneutral) and experiment 2 had two phases (increased room temperature/endophyte treatment and thermoneutral). During endophyte treatment phases, heifers were fed their respective treatment seed. During all other phases, all heifers received E- seed. In experiment 1, proportions of lymphocytes producing interferon-γ were decreased in E+ heifers during the heat/endophyte phase (P=0.03) whereas during the subsequent thermoneutral period this response was greater in high, compared with low, EV heifers on E- treatment, with no difference observed among E+ heifers (interaction P=0.08). Also during the recovery phase, average lymphocyte production of interferon-γ was higher in E+ heifers (P=0.01). Consistent with experiment 1 findings, during the recovery period of experiment 2, endophyte exposure increased the per cell production of interferon-γ (P<0.01). In this experiment, the difference was of sufficient magnitude to result in a concomitant increase (P=0.03) in total interferon-γ production during that period. These results indicate peripheral lymphocyte production of interferon-γ can be influenced by both EV and endophyte exposure following periods of increased ambient temperature humidity indices, though there was minimal indication of interactions between temperament and alkaloid exposure. This may imply that cattle with high exit velocities and those previously exposed to toxic endophyte-infected tall fescue are better poised against cell-mediated challenges.

Supplementing pre- and probiotic ingredients to feedlot steers: effects on health, growth performance, and physiological responses

Feedlot diets are often enriched with additives to mitigate health disorders and promote cattle performance, including the feed-grade antimicrobials monensin and tylosin. However, alternative feeding strategies are warranted given the increasing regulations regarding the use of antimicrobials in feedlot diets. This study evaluated the performance, physiological, and health responses of feedlot cattle offered a synbiotic supplement (yeast-derived prebiotic + Bacillus subtilis probiotic), which replaced or was fed in conjunction with monensin and tylosin. Angus-influenced steers (n = 192) from four different cowherds were weaned on day -1 and transported (800 km) to the feedlot. Steers were allocated to 1 of 24 pens (eight steers/pen) upon arrival on day 0. Pens were assigned to receive (n = 8/treatment) a total-mixed ration (TMR) containing: (1) monensin and tylosin (RT; 360 mg/steer daily from Rumensin and 90 mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN, USA), (2) yeast-derived ingredient and B. subtilis probiotic (CC; 18 g/steer daily of Celmanax and 28 g/steer daily of Certillus; Church and Dwight Co., Inc., Princeton, NJ, USA), or (3) a combination of RT and CC (RTCC). Steers were slaughtered according to BW in four groups balanced by treatment and pens and received treatments for 252 ± 4 days. No treatment effects were detected (P ≥ 0.17) for steer BW gain and morbidity responses. Mean TMR intake was greater and gain:feed ratio was less (P ≤ 0.01) in CC compared with RT and RTCC steers. Mean plasma leptin concentration was greater (P ≤ 0.05) in CC compared with RT and RTCC steers. Steers receiving CC had greater (P ≤ 0.04) concentrations of plasma cortisol, haptoglobin, glucose, and beta-hydroxybutyrate, and less (P ≤ 0.05) concentration of non-esterified fatty acids compared with RT and RTCC steers on day 14 of the experiment. Carcass marbling was greater (P = 0.01) in CC compared with RT steers and tended to be greater (P = 0.07) in RTCC compared with RT steers. Proportion of carcasses that graded Choice or better and Longissimus muscle area were greater (P ≤ 0.05) in CC and RTCC compared with RT steers. Incidence of liver abscesses was less (P = 0.01) in RTCC compared with CC steers and tended to be less (P = 0.09) in RT compared with CC steers. Results from this experiment indicate that the synbiotic supplement may replace monensin and tylosin without reducing steer BW gain, with potential improvements to carcass quality traits.

Welfare of cattle during transport

In the framework of its Farm to Fork Strategy, the Commission is undertaking a comprehensive evaluation of the animal welfare legislation. The present Opinion deals with protection of cattle (including calves) during transport. Welfare of cattle during transport by road is the main focus, but other means of transport are also covered. Current practices related to transport of cattle during the different stages (preparation, loading/unloading, transit and journey breaks) are described. Overall, 11 welfare consequences were identified as being highly relevant for the welfare of cattle during transport based on severity, duration and frequency of occurrence: group stress, handling stress, heat stress, injuries, motion stress, prolonged hunger, prolonged thirst, respiratory disorders, restriction of movement, resting problems and sensory overstimulation. These welfare consequences and their animal-based measures are described. A variety of hazards, mainly relating to inexperienced/untrained handlers, inappropriate handling, structural deficiencies of vehicles and facilities, poor driving conditions, unfavourable microclimatic and environmental conditions, and poor husbandry practices leading to these welfare consequences were identified. The Opinion contains general and specific conclusions relating to the different stages of transport for cattle. Recommendations to prevent hazards and to correct or mitigate welfare consequences have been developed. Recommendations were also developed to define quantitative thresholds for microclimatic conditions within the means of transport and spatial thresholds (minimum space allowance). The development of welfare consequences over time was assessed in relation to maximum journey duration. The Opinion covers specific animal transport scenarios identified by the European Commission relating to transport of unweaned calves, cull cows, the export of cattle by livestock vessels, the export of cattle by road, roll-on-roll-off ferries and 'special health status animals', and lists welfare concerns associated with these.

Limitations of bacterial culture, viral PCR, and tulathromycin susceptibility from upper respiratory tract samples in predicting clinical outcome of tulathromycin control or treatment of bovine respiratory disease in high-risk feeder heifers

A cross-sectional prospective cohort study including 1026 heifers administered tulathromycin due to high risk of clinical signs of bovine respiratory disease (BRD), measured poor association between BRD clinical outcomes and results of bacterial culture and tulathromycin susceptibility from BRD isolates of deep nasopharyngeal swabs (DNS) and adequate association with viral polymerase chain reaction (PCR) results from nasal swabs. Isolation rates from DNS collected on day-0 and at 1st BRD-treatment respectively were: Mannheimia haemolytica (10.9% & 34.1%); Pasteurella multocida (10.4% & 7.4%); Mycoplasma bovis (1.0% & 36.6%); and Histophilus somni (0.7% & 6.3%). Prevalence of BRD viral nucleic acid on nasal swabs collected exclusively at 1st BRD-treatment were: bovine parainfluenza virus type-3 (bPIV-3) 34.1%; bovine viral diarrhea virus (BVDV) 26.3%; bovine herpes virus type-1 (BHV-1) 10.8%; and bovine respiratory syncytial virus (BRSV) 54.1%. Increased relative risk, at 95% confidence intervals, of 1st BRD-treatment failure was associated with positive viral PCR results: BVDV 1.39 (1.17-1.66), bPIV-3 1.26 (1.06-1.51), BHV-1 1.52 (1.25-1.83), and BRSV 1.35 (1.11-1.63) from nasal swabs collected at 1st BRD-treatment and culture of M. haemolytica 1.23 (1.00-1.51) from DNS collected at day-0. However, in this population of high-risk feeder heifers, the predictive values of susceptible and resistant isolates had inadequate association with BRD clinical outcome. These results indicate, that using tulathromycin susceptibility testing of isolates of M. haemolytica or P. multocida from DNS collected on arrival or at 1st BRD-treatment to evaluate tulathromycin clinical efficacy, is unreliable.

Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: postweaning responses of offspring reared as replacement heifers or feeder cattle

One hundred and ninety nonlactating, pregnant beef cows (¾ Bos taurus and ¼ Bos indicus; 138 multiparous and 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (day 0). Cows were ranked by parity, pregnancy type (artificial insemination = 102, natural service = 88), body weight (BW) and body condition score, and assigned to receive a supplement containing: (1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 95) or (2) an organic complexed source of Cu, Mn, Co, and Zn (AAC; Availa4; Zinpro Corporation, Eden Prairie, MN; n = 95). The INR and AAC provided the same daily amount of Cu, Co, Mn, and Zn, based on 7 g of the AAC source. From day 0 to calving, cows were maintained in a single pasture and segregated 3 times weekly into 1 of 24 individual feeding pens to receive treatments. Calves were weaned on day 367 (200 ± 2 d of age), managed as a single group for a 45-d preconditioning period (days 367 to 412), and transferred to a single oat (Avena sativa L.) pasture on day 412. Heifer calves were moved to an adjacent oat pasture on day 437, where they remained until day 620. Heifer puberty status was verified weekly (days 437 to 619) based on plasma progesterone concentrations. Steer calves were shipped to a commercial feedlot on day 493, where they were managed as a single group until slaughter (day 724). Plasma cortisol concentration was greater (P = 0.05) in AAC calves at weaning but tended to be less (P = 0.10) on day 370 compared with INR calves. Mean plasma haptoglobin concentration was greater (P = 0.03) in INR vs. AAC calves during preconditioning, and no treatment effects were noted (P = 0.76) for preconditioning average daily gain (ADG). Puberty attainment was hastened in AAC heifers during the experiment (treatment × day; P < 0.01), despite similar (P = 0.39) ADG between treatments from days 412 to 620. Expression of myogenin mRNA in the longissimus muscle was greater (P = 0.05) in INR vs. AAC heifers on day 584. No treatment effects were detected (P ≥ 0.24) for steer ADG from day 412 until slaughter, nor for carcass quality traits. Hepatic mRNA expression of metallothionein 1A was greater (P = 0.02) in INR vs. AAC steers on day 586. In summary, supplementing Co, Cu, Zn, and Mn as organic complexed instead of sulfate sources to beef cows during the last 5 mo of gestation did not improve performance and physiological responses of the steer progeny until slaughter, but hastened puberty attainment in the female progeny reared as replacement heifers.

Appeasing Pheromones against Bovine Respiratory Complex and Modulation of Immune Transcript Expressions

Bovine respiratory disease is still a major concern and has major economic impact. Another consequence of respiratory infections is the use of antimicrobial molecules to control bacterial pathogens. This can participate in the emergence and shedding of antimicrobial resistance that can threaten animal as well as human health. Appeasing pheromones with their capacity to reduce stress and thus their ability to preserve the functions of the immune system have been proposed to reduce the use of antimicrobial substances. In this study, we assessed the effect of appeasing pheromone administration on bovine health and performance during the fattening period. Zootechnical and health parameters and whole blood immune transcript expressions were measured over four weeks in bulls to determine the effect of the pheromone. We observed increased clinical signs on Day 8 (D8) and decreased clinical signs on D30 in bulls who received the pheromone and a higher expression of interleukin 8 transcripts in this group than in the control group on D8. Our results are overall in line with previous reports in livestock species. Further studies are needed to shed more light on the effect of appeasing pheromones and decipher their exact mechanisms of action.

Performance, health, and physiological responses of newly received feedlot cattle supplemented with pre- and probiotic ingredients

Nutritional strategies that optimize immunity of feedlot cattle are warranted due to increasing regulations with the use of feed-grade antimicrobials. This study evaluated physiological, health, and performance responses of cattle receiving a synbiotic supplement (yeast-derived prebiotic + Bacillus subtilis probiotic), which replaced feed-grade antimicrobials or were fed in conjunction with monensin during the initial 45 days in the feedlot. Angus-influenced steers (n = 256) were acquired from an auction facility on day -2, and transported (800 km) to the feedlot. Shrunk BW was recorded upon arrival (day -1). Steers were allocated to 1 of 18 pens (day 0), and pens were assigned to receive (n = 6/treatment) a free-choice diet containing: (1) monensin and tylosin (RT; 360 mg/steer daily from Rumensin and 90 mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN, USA), (2) yeast-derived ingredient and B. subtilis probiotic (CC; 18 g/steer daily of Celmanax and 28 g/steer daily of Certillus; Church and Dwight Co., Inc., Princeton, NJ, USA), or (3) monensin in addition to yeast-derived and B. subtilis ingredients (RCC) as in RT and CC. Steers were assessed for bovine respiratory disease (BRD) and DMI daily. Steer BW was recorded on days 45 and 46, and averaged for final BW. Blood samples were collected on days 0, 7, 17, 31, and 45. Feed intake was greater (P ≤ 0.05) in CC vs. RCC and RT during the initial 3 weeks upon feedlot arrival. No treatment differences were noted (P ≥ 0.41) for average daily gain, BW, and feed efficiency. Incidence of BRD did not differ (P = 0.77) between treatments (average 80.1%). A greater proportion (P ≤ 0.03) of RT steers diagnosed with BRD required a second antimicrobial treatment compared with CC and RCC (57.3, 37.3, and 38.6%, respectively). Removal of steers from the trial due to severe morbidity + mortality was greater (P = 0.02) in RT vs. CC (22.4 and 7.0%), and did not differ (P ≥ 0.16) among RCC (12.9%) vs. RT and CC. Plasma glucose concentrations were greater (P ≤ 0.02) in CC vs. RCC and RT on day 7. Plasma concentrations of nonesterified fatty acids were greater (P ≤ 0.02) in RT and RCC vs. CC on day 7, and in RT vs. CC on day 17. Steers receiving the synbiotic supplement had improved response to BRD treatment, suggesting heightened immunocompetence from partially enhanced metabolism and the nutraceutical effects of B. subtilis and yeast compounds.

Administering an appeasing substance to optimize performance and health responses in feedlot receiving cattle

This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) at feedlot entry to receiving cattle. Angus-influenced steers (n = 342) from 16 sources were purchased from an auction yard on day -1, and transported (12 hr; 4 trucks) to the feedlot. Upon arrival on day 0, shrunk body weight (BW; 240 ± 1 kg) was recorded and steers were ranked by load, shrunk BW, and source and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 171) or placebo (diethylene glycol monoethyl ether; CON; n = 171). The BAS is a mixture of fatty acids that replicate the composition of the bovine appeasing pheromone. Treatments (5 mL) were topically applied to each individual steer on their nuchal skin area. Steers were allocated to 1 of 24 drylot pens (12 pens/treatment) and received a free-choice diet until day 46. Steers were assessed daily for bovine respiratory disease (BRD) signs, and feed intake was recorded from each pen daily. Steer unshrunk BW was recorded on days 7, 17, 31, 45, and 46. Shrunk BW on day 0 was added an 8% shrink to represent initial BW, and final BW was calculated by averaging BW from days 45 and 46. Blood samples were collected from 5 steers/pen on days 0, 7, 11, 31, and 45. Pen was considered the experimental unit. Steer BW gain was greater (P = 0.04) in BAS vs. CON (1.01 vs. 0.86 kg/d, SEM = 0.05). Feed intake did not differ (P = 0.95) between treatments, resulting in greater (P = 0.05) feed efficiency in BAS vs. CON (171 vs. 142 g/kg, SEM = 10). Plasma cortisol concentration was greater (P = 0.05) and plasma glucose concentration was less in CON vs. BAS on day 7 (treatment × day; P = 0.07 and <0.01, respectively). Mean plasma β-hydroxybutyrate concentration was greater (P < 0.01) in BAS vs. CON (3.23 and 2.75 mg/mL; SEM = 0.12). Incidence of BRD was greater (P ≤ 0.05) in BAS vs. CON from days 6 to 10 and days 19 to 23 (treatment × day; P < 0.01), although overall BRD incidence did not differ (P = 0.20) between treatments (82.4% vs. 76.6%, respectively; SEM = 3.2). A greater proportion (P = 0.04) of BAS steers diagnosed with BRD required one antimicrobial treatment to regain health compared with CON (59.3% vs. 47.6%, SEM = 4.2). Hence, BAS administration to steers upon feedlot arrival improved BW gain during a 45-d receiving period by enhancing feed efficiency. Moreover, results suggest that BAS improved steer performance by facilitating early detection of BRD signs, lessening the disease recurrence upon first antimicrobial treatment.

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.

Lipopolysaccharide triggers different transcriptional signatures in taurine and indicine cattle macrophages: Reactive oxygen species and potential outcomes to the development of immune response to infections

Macrophages are classified upon activation as classical activated M1 and M2 anti-inflammatory regulatory populations. This macrophage polarization is well characterized in humans and mice, but M1/M2 profile in cattle has been far less explored. Bos primigenius taurus (taurine) and Bos primigenius indicus (indicine) cattle display contrasting levels of resistance to infection and parasitic diseases such as C57BL/6J and Balb/c murine experimental models of parasite infection outcomes based on genetic background. Thus, we investigated the differential gene expression profile of unstimulated and LPS stimulated monocyte-derived macrophages (MDMs) from Holstein (taurine) and Gir (indicine) breeds using RNA sequencing methodology. For unstimulated MDMs, the contrast between Holstein and Gir breeds identified 163 Differentially Expressed Genes (DEGs) highlighting the higher expression of C-C chemokine receptor type five (CCR5) and BOLA-DQ genes in Gir animals. LPS-stimulated MDMs from Gir and Holstein animals displayed 1,257 DEGs enriched for cell adhesion and inflammatory responses. Gir MDMs cells displayed a higher expression of M1 related genes like Nitric Oxide Synthase 2 (NOS2), Toll like receptor 4 (TLR4), Nuclear factor NF-kappa-B 2 (NFKB2) in addition to higher levels of transcripts for proinflammatory cytokines, chemokines, complement factors and the acute phase protein Serum Amyloid A (SAA). We also showed that gene expression of inflammatory M1 population markers, complement and SAA genes was higher in Gir in buffy coat peripheral cells in addition to nitric oxide concentration in MDMs supernatant and animal serum. Co-expression analyses revealed that Holstein and Gir animals showed different transcriptional signatures in the MDMs response to LPS that impact on cell cycle regulation, leukocyte migration and extracellular matrix organization biological processes. Overall, the results suggest that Gir animals show a natural propensity to generate a more pronounced M1 inflammatory response than Holstein, which might account for a faster immune response favouring resistance to many infection diseases.

Effects of long-distance transportation on blood constituents and composition of the nasal microbiota in healthy donkeys

BACKGROUND

This study aims to determine the effects of transportation on the nasal microbiota of healthy donkeys using 16S rRNA sequencing.

RESULTS

Deep nasal swabs and blood were sampled from 14 donkeys before and after 21 hours' long-distance transportation. The values of the plasma hormone (cortisol (Cor), adrenocorticotrophic hormone (ACTH)), biochemical indicators (total protein (TP), albumin (ALB), creatinine (CREA), lactic dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase (CK), blood urea (UREA), plasma glucose (GLU)) and blood routine indices (white blood cell (WBC), lymphocyte (LYM), neutrophil (NEU), red blood cell (RBC), hemoglobin (HGB)) were measured. 16S rRNA sequencing was used to assess the nasal microbiota, including alpha diversity, beta diversity, and phylogenetic structures. Results showed that levels of Cor, ACTH, and heat-shock protein 90 (HSP90) were significantly increased (p < 0.05) after long-distance transportation. Several biochemical indicators (AST, CK) and blood routine indices (Neu, RBC, and HGB) increased markedly (p < 0.05), but the LYM decreased significantly (p < 0.05). Nine families and eight genera had a mean relative abundance over 1%. The predominant phyla in nasal microbiota after and before transportation were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Transportation stress induced significant changes in terms of nasal microbiota structure compared with those before transportation based on principal coordinate analysis (PCoA) coupled with analysis of similarities (ANOSIM) (p < 0.05). Among these changes, a notably gain in Proteobacteria and loss in Firmicutes at the phylum level was observed.

CONCLUSIONS

These results suggest transportation can cause stress to donkeys and change the richness and diversity of nasal microbiota. Further studies are required to understand the potential effect of these microbiota changes on the development of donkey respiratory diseases.

To what extent does the composition of batches formed at the sorting facility influence the subsequent growth performance of young beef bulls? A French observational study

To meet the demands of the beef cattle sector in France, weaned beef calves are transported to sorting facilities and sorted into batches composed of animals of similar body weight (BW) before the beginning of the fattening period. This procedure aims to facilitate animal management. However, it leads to practices that affect animal welfare, health and performance, such as transporting weaned beef calves over long distances and mixing animals originating from different cow/calf farms. In contrast, other potentially beneficial practices, such as pre-weaning vaccination against bovine respiratory diseases (BRD), are seldom taken into consideration when batches are formed. This observational study, based on field data from 15,735 Charolais bulls, aimed to investigate which criteria should be favored for batch constitution by quantifying the effect of batch characteristics on the growth performance of young bulls during the fattening period. Clustering analysis was used to group young bulls exhibiting similar batch characteristics and define batch types. Associations between batch characteristics/batch types and individual growth performance/homogeneity of growth performance (mean and standard deviation (SD) of average daily gain (ADG) and fattening period duration) were studied using linear mixed models. The mean BW and the percentage of animals vaccinated against BRD before weaning were positively associated with ADG (+35 g/d for each additional 50 kg and +28 g/d for a high percentage of vaccinated animals, P < 0.05). In contrast, transportation distance was negatively associated with ADG (-12 g/d for each additional 120 km travelled). Mixing animals and BW homogeneity did not affect growth performance (P > 0.05). Only the mean BW and mixing animals negatively influenced the homogeneity of ADG (P < 0.01). The clustering analysis revealed that batches with the most BW heterogeneity, the least mixing, the shortest transportation distance and a high percentage of pre-weaning animals vaccinated against BRD had better growth performance compared to batches with the opposite characteristics (+61 g/d, P < 0.001). Our results suggest that major improvements of growth performance of fattening young bulls could be obtained by minimizing transportation distance, providing vaccination programs against BRD before weaning, and maintaining groups from the same cow/calf farm instead of constituting groups of animals with similar BW at the beginning of fattening.

Effect of bovine genotype on innate immune response of heifers to repeated lipopolysaccharide (LPS) administration

This pilot study provides a preliminary assessment of the impact of genotype on acute innate immune pro-inflammatory, metabolic and endocrine responses to repeated lipopolysaccharide (LPS) administered to growing heifers. Heifers (n = 4/genotype) were from unselected (stable milk yield since 1964, UH) or contemporary (CH) Holstein cows that differed in milk yield (6200 vs 11,100 kg milk/305 d) or from contemporary Black Angus (CA) cows bred to contemporary Red Angus bulls. Heifers were challenged with iv administration of 0.5 μg LPS/kg body weight on day 1 (Challenge 1) and d 5 (Challenge 2) of study to assess endotoxin tolerance. Plasma was collected at -1, -0.5, 0, 1, 2, 3, 4, 6, 8, and 24 h relative to each LPS administration. Rectal body temperature (BT) was measured before each blood sampling and at 5 and 7 h. Data were analyzed by repeated measures with sampling time as the repeated effect. Each genotype had at least one pro-inflammatory response that indicated it might have a more robust response than the other genotypes. The CH heifers had a greater TNF-α response, UH heifers had greater IL-6 and XO responses and CA heifers had greater BT and SAA response to LPS than the other genotypes. There was a genotype by time by interaction as cortisol peaked earlier in CH and UH than in CA heifers. Glucose response was less in CA and insulin response was greater in CH heifers. Endotoxin tolerance to LPS was evident as pro-inflammatory, cortisol, glucose and insulin responses were less during Challenge 2 than during Challenge 1. Differences among genotypes during Challenge 1 were eliminated during Challenge 2 except for the greater SAA response in CA heifers and indicate the potential for differential impacts of genotype on the development of endotoxin tolerance. Specific reasons for these effects of genotype are not clear from these data but the results support the hypothesis for differential innate immune signaling among these bovine genotypes.

Effects of Separation of Cows and Calves on Reproductive Performance and Animal Welfare in Tropical Beef Cattle

Nursing a calf suppresses postpartum ovarian activity prolonging the period of anestrus. Diverse methods are used to reduce the effect of suckling; the most popular, restricted suckling, reduces the number of encounters mother-calf. Temporal weaning of the calf for periods of 24 h, 48 h, or even 72 h also suppress the effect of suckling and is commonly applied to cow-calf operations in the tropics. Early weaning of the calf, usually three to five months after birth, is a practice gaining popularity over the traditional system of weaning at seven months. Furthermore, the use of nose-flaps in the calf to avoid suckling is a common procedure in South America. Finally, weaning during the first week after calving is an established method to reduce postpartum anestrus. The objective of the present review is to discuss the effects of these methods on the reproductive performance of beef cattle and their animal welfare implications.

The Effects of Sea and Road Transport on Physiological and Electroencephalographic Responses in Brahman Crossbred Heifers

Simple Summary

This study investigated the effect of sea and road transport on the physiological response of cattle. The animals were transported by sea (14 d) from Darwin Port, Australia, to Pasir Gudang Port, Johor, Malaysia. Thereafter, the animals were road transported (330 km) from Pasir Gudang Port to Universiti Putra Malaysia (UPM). From the results of the various blood stress indicators and brain activity of the animals, both sea and road journeys were found to be stressful to the animals. However, the animals recovered from the stressful transport journeys following 4 and 7 days post-transport.

Abstract

The objective of the current study was to evaluate the effects of sea and road transport on the acute phase proteins (APP), cortisol, metabolic, haematological and electroencephalographic (EEG) responses of Brahman crossbred heifers. Sixty Brahman crossbred heifers were subjected to 14 d of transportation by sea from Darwin Port, Australia, to Pasir Gudang Port, Johor, Malaysia, and 330 km of road transportation. Results revealed that the intensity of response for most blood biochemical parameters increased significantly and were different from the baseline values taken while the animals were in Darwin Port, Australia. Haematological results obtained also revealed a significant increase and were different from the baseline values. Cortisol and APP (bovine alpha 1-acid glycoprotein and serum amyloid-A) values increased significantly and were different from the baseline values. Haematological parameters, APP, cortisol and EEG data (alpha, beta, delta and theta waves, total power and median frequency) decreased significantly following 4 and 7 days post-transport, suggesting a recovery of the animals from the stressfulness of transport. In conclusion, the current results revealed that the concentrations of biochemical and haematological parameters, cortisol, APP and EEG data were affected by both sea and road transport as evidenced by the significant changes recorded from the parameters above.

Effects of vaccination timing against respiratory pathogens on performance, antibody response, and health in feedlot cattle

Angus × Hereford calves (n = 159; 87 heifers and 72 steers) were ranked by sex, BW, and age, and assigned to one of three vaccination schemes against bovine respiratory disease (BRD): (i) vaccination at weaning (day 0) and revaccination at feedyard arrival (day 30; CON, n = 53), (ii) vaccination 15 d before weaning (day -15) and revaccination 15 d before feedyard arrival (day 15; EARLY, n = 53), and (iii) vaccination 15 d after weaning (day 15) and revaccination 15 d after feedyard arrival (day 45; DELAYED, n = 53). Calves were maintained on pasture from days -15 to 29, transported (day 30) for 480 km to a commercial growing feedyard, and moved (day 180) to an adjacent finishing yard where they remained until slaughter (day 306). Calf BW was recorded on two consecutive days (days -15, -14, 0, 1, 29, 30, 75, 76, 179, and 180), which were averaged for BW gain calculation. Calves were assessed for BRD signs daily from days 0 to 306. Blood samples were collected on days -15, 0, 15, 30, 45, 60, and 75. No treatment effects were detected (P ≥ 0.49) for BW responses and carcass characteristics (P ≥ 0.32). Serum titers against bovine viral diarrhea type 1 were greater (P ≤ 0.05) in EARLY vs. CON and DELAYED from days 15 to 45, and greater (P < 0.01) in CON vs. DELAYED on days 30 and 45. Serum titers against bovine herpesvirus-1 were greater (P < 0.01) in EARLY vs. CON and DELAYED on days 0 and 30, and greater (P < 0.01) in EARLY and CON vs. DELAYED on days 15 and 45. Serum titers against bovine respiratory syncytial virus were greater (P = 0.05) in EARLY vs. CON on day 0, greater (P = 0.04) in CON vs. DELAYED on day 15, and greater (P ≤ 0.03) in EARLY and CON vs. DELAYED from days 30 to 60. Serum titers against parainfluenza3 virus were greater (P ≤ 0.04) in EARLY vs. DELAYED on days 30 and 45, and greater (P < 0.01) in CON vs. DELAYED on day 30. Incidence of BRD was less (P = 0.04) in EARLY vs. CON and DELAYED, and similar (P = 0.99) between CON and DELAYED. Therefore, altering the time of vaccination and revaccination against BRD to provide both doses prior to feedlot entry altered serum antibody responses to BRD pathogens, and alleviated the incidence of this disease in feedlot cattle.

Influence of prenatal transportation stress on innate immune response to an endotoxin challenge in weaned Brahman bull calves†,‡

The objective of this study was to assess the influence of prenatal stress (PNS) on innate immune responses to an endotoxin challenge in weaned bull calves. Altered innate immune response to lipopolysaccharide (LPS), as characterized by changes in a range of variables was hypothesized in PNS bull calves. Brahman cows (n = 96; 48 stressed by transportation at five stages of gestation and 48 Controls) produced 85 calves, from which 16 uncastrated male (bull) calves from each PNS and Control treatment were selected for an LPS challenge period. Rectal temperature (RT), sickness behavior score (SBS), serum concentrations of cortisol, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and complete blood count (CBC) variables were assessed in response to intravenous LPS (0.25 μg/kg body weight) administration. Each reported variable increased or decreased following LPS administration. Prior to LPS, PNS bull calves exhibited increased TNF-α, IL-6, and monocyte counts, but decreased IFN-γ, eosinophils, and basophils (p < .05). Compared with Control, in response to LPS, PNS bull calves exhibited greater circulating concentrations of cortisol. PNS bull calves exhibited lower (p < .05) eosinophil and basophil counts at time 0 (time of LPS administration) but similar counts to Control bull calves 2 h after LPS. PNS bull calves exhibited a greater change from baseline for IFN-γ and monocytes in response to LPS administration. No other variables were influenced by prenatal treatment (p > .05). These findings suggest that PNS did not adversely affect basal or induced components of the innate immune response to an immunological challenge. Lay summary Our laboratory studied the influence of prenatal stress (i.e., transportation of pregnant cows) on immune function of bull calves at 8 months of age. This was accomplished by studying aspects of their innate immune response to an immunological challenge. Prenatal stress did not adversely affect basal or induced components of the innate immune response to an immunological challenge.

Effects of dietary energy level and intake of corn by-product-based diets on newly received growing cattle: antibody production, acute phase protein response, stress, and immunocompetency of healthy and morbid animals

Effects of dietary energy level and intake of corn by-product-based diets on antibody production, acute phase protein response, stress, and immunocompetency of healthy and morbid newly received growing cattle were evaluated. Four dietary treatments were formulated to supply 0.99, 1.10, 1.21, and 1.32 Mcal NEg/ kg DM and were offered at 100%, 95%, 90%, and 85% of ad libitum based on 0.99/100 treatment intake, respectively. Thirty-two pens were utilized with approximately 12 animals/pen. Four animals from each pen (32/dietary treatment) were randomly selected and used to serve as a subset to monitor immune function and acute phase proteins following a split-plot design. In addition, two animals were randomly and independently selected from each pen (16/dietary treatment) and used to measure fecal cortisol metabolite. Additionally, animals removed from the pen one (M1), two (M2), or three (M3) times and classified as morbid were bled in conjunction with a healthy control (H) removed at the same time and the serum analyzed for the same parameters. A quadratic response to time (P < 0.01) was detected for haptoglobin concentrations and for antibody titers for bovine viral diarrhea type 1 (BVD-I) and infectious bovine rhinotracheitis (IBR; P < 0.01). Haptoglobin was lowest on arrival, highest on day 14, and similar to baseline levels by day 27. Titer levels for BVD-I and IBR were lowest on arrival, higher on day 14, and significantly higher on day 27. Titers for bovine viral diarrhea type 2 (BVD-II) responded linearly (P < 0.05) with lower levels on arrival and highest levels on day 27. Haptoglobin was elevated in morbid animals compared to healthy pen mates (P < 0.05). Titer levels for BVD-I and IBR were also higher in healthy animals compared to animals pulled for morbidity (P < 0.01). Fecal cortisol was higher on arrival than on day 14 (P < 0.05). Dietary treatment had no effect on any of the parameters investigated. In summary, high-energy receiving diets based on fermentable fiber from by-products can be fed to newly received growing cattle without negative effects on antibody production toward vaccines, inflammation, or overall stress. In addition, haptoglobin concentrations and titer levels for BVD-I and IBR viruses are higher in healthy animals compared to sick animals.

Evaluation of tropically adapted straightbred and crossbred beef cattle: Cortisol concentration and measures of temperament at weaning and transport

The objective of this research was to evaluate circulating concentrations of plasma cortisol and measures of temperament at weaning in calves (steers and heifers) and at transport in steers. Calves ( = 993) were produced from a 3-breed diallel mating design that included calves from 3 consecutive years. Breed types of calves were straightbred Angus (A), Brahman (B), and Romosinuano (R) and all F crossbred combinations (AB, BA, AR, RA, BR, and RB). At weaning (d 0) and at 24 and 72 h after weaning, blood was sampled from calves and the plasma was stored for later cortisol assay. Additionally, at each of these times, temperament was assessed as chute score, exit velocity, and pen score. About 1 mo later, steer calves ( = 471) were sampled before shipment, at arrival, and at 24 h, 72 h, 2 wk, and 4 wk after shipment (2,025 km; Brooksville, FL, to El Reno, OK). At each of these sampling times, blood was collected and plasma was stored for subsequent cortisol assay and temperament was assessed by measurement of exit velocity. At both weaning and transport, plasma concentrations of cortisol did not significantly differ ( > 0.05) among straightbreds or among crossbreds. Significant ( < 0.05) positive genetic effects were observed for plasma concentration of cortisol at weaning (heterosis for BA and direct Romosinuano effect) and transport (heterosis for RA, BR, and BA; direct Romosinuano effect; and maternal Angus effect). Assessment of temperament using the objective measurement of exit velocity or the subjective measures of chute score or pen score (1 [lowest] to 5 [highest excitability] scale, based on behavior in chute and behavior in pen with human observer, respectively) generally provided similar results: Brahman was higher than Brahman crosses, which were higher than Angus, Romosinuano, and their reciprocal crosses. For exit velocity, however, Brahman did not differ from Brahman crosses and Angus did not differ from Romosinuano or Brahman crosses. At transport, sire breed and dam breed affected exit velocity of steers, with higher ( < 0.05) estimates for Brahman than for Romosinuano or Angus. These data suggest that weaned calves and shipped steers of various breed types show a similar response to stressors in cortisol concentration. In contrast, in assessing temperament or behavioral response to humans, Romosinuano and Angus had better temperaments and were less excitable than Brahman.

Invited review: Relationship between cattle transport, immunity and respiratory disease

The association between transportation and the occurrence of the bovine respiratory disease complex (BRDC) has long been recognised. Many hypotheses regarding this association have been declared through the past decades, and it is agreed upon by most researchers that the multiple stressors that calves experience during transportation result in an overall immunosuppression that allows the respiratory tract to be invaded by numerous opportunistic pathogens. Furthermore, the innate immune cells, neutrophils, may be trapped in a paradox whereby their crucial defence and pathogen-killing activities are counteracted by excessive inflammation and tissue damage that may exacerbate disease, including the BRDC. Neutrophilia in response to glucocorticoids has been attributed to an influx of immature neutrophils newly released from the bone marrow, a decrease in neutrophil margination along endothelial walls, and a decrease in neutrophil apoptosis. Several of these explanations have been confirmed by altered expression of genes and proteins important for neutrophil margination and apoptosis.

Dexamethasone treatment differentially alters viral shedding and the antibody and acute phase protein response after multivalent respiratory vaccination in beef steers

Our objective was to examine immunosuppression induced by dexamethasone (DEX) administration in cattle on immunological responses to a multivalent respiratory vaccine containing replicating and nonreplicating agents. Steers ( = 32; 209 ± 8 kg) seronegative to infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), and parainfluenza-3 virus (PI3V) were stratified by BW and randomly assigned to 1 of 3 treatments: 1) acute immunosuppression (ACU; 0.5 mg/kg BW DEX intravenously at 1000 h only on d 0), 2) chronic immunosuppression (CHR; 0.5 mg/kg BW DEX intravenously at 1000 h on d -3 to 0), or 3) a control (CON; no DEX). On d -4, steers were fitted with intravenous catheters in the jugular vein and placed into individual stanchions. At 1200 h on d 0, steers were administered a respiratory vaccine containing modified-live virus (MLV) isolates of IBRV, BVDV, BRSV, and PI3V and a (MH) toxoid. On d 4, cattle were transported (177 km) and housed in an isolated outdoor pen. Serum was harvested on d 0, 7, 14, 21, 28, 35, 42, and 56 to determine IBRV-, BVDV-, BRSV-, and PI3V-specific antibody titers and MH whole cell and leukotoxin antibody concentrations. Sera from d -2, 0, 1, 3, 7, and 14 were used to quantify haptoglobin (Hp) concentration and ceruloplasmin (Cp) activity. Nasal swab specimens were collected on d 0, 3, and 14 to determine the presence of IBRV, BVDV, BRSV, and PI3V via PCR analysis. There was a treatment × day interaction ( < 0.01) such that CHR steers had a greater ( ≤ 0.07) BVDV antibody titer on d 14, 21, and 28. Moreover, IBRV-specific antibodies increased beginning on d 14 for CHR and on d 28 for ACU and remained greater through d 56 compared with CON ( ≤ 0.03). Conversely, serum MH whole cell antibody concentration was least ( ≤ 0.06) for CHR from d 7 to 28 and greatest for CON ( ≤ 0.04) on d 56. Treatment altered Hp such that CON exhibited a greater ( < 0.01) Hp concentration than CHR but was not different from ACU ( = 0.16). On d 3, Cp was greatest for CON, intermediate for ACU, and least for CHR (treatment × day; ≤ 0.01). The prevalence of IBRV and BVDV in nasal swabs on d 14 was 67 and 56%, respectively, for CHR; 10 and 10%, respectively, for CON; and 9 and 0%, respectively, for ACU ( ≤ 0.006). Results suggest that CHR allowed increased replication of MLV vaccine agents. Conversely, DEX-induced immunosuppression blunted the acute phase protein and antibody response against the nonreplicating MH toxoid.

Effects of two-stage weaning with nose flap devices applied to calves on cow body condition, calf performance, and calf humoral immune response

The effects of nose flap devices in calves before dam separation on cow BCS, pre- and postseparation calf performance, and humoral immune response were compared with traditional weaning. Primiparous and multiparous Angus and Hereford cows ( = 113) and their Angus, Hereford, and Angus × Hereford calves (179.4 ± 3.92 kg and 161 ± 22.7 d of age) were used. Cow-calf pairs were allocated to 1 of 2 treatments in a completely randomized design: 1) nose flap for 21 d before separation from the dam (NF) or 2) no nose flap for 21 d before separation from the dam (CON). Calves were separated from dams on d 0, and calves were placed in group feed-yard pens for 28 d. A subset ( = 75) of weaned calves were placed into 1 of 8 pens to evaluate DMI. Cow BCS was measured on d -21 and 56, and calves were given modified live vaccinations (d -21 and 1), challenged with ovalbumin (OVA; d 1), and weighed (d -21, 1, 7, 14, 21, and 28). In addition, blood samples were collected (d -21, 1, 14, and 28) to measure primary humoral immune response. Control calves tended to have greater BW on d 14 ( = 0.09) and 21 ( = 0.07) than NF calves, and CON calves had greater ( < 0.05) ADG from d -21 to 1 vs. NF calves. Treatments did not differ ( ≥ 0.27) for postweaning DMI, G:F, or morbidity. Serum neutralization tests for bovine viral diarrhea virus type 1 (BVDV-1) and bovine herpesvirus type 1 (BHV-1) were used to measure humoral response to a viral vaccination. Serum antibody titers to BVDV-1 for CON calves tended ( = 0.08) to be greater on d 1 and were greater ( < 0.05) by d 28 vs. NF calves. By d 28, a greater percentage ( < 0.05) of CON calves seroconverted for BVDV-1 than NF calves (82.1 vs. 66.7%, respectively). Serum antibody titers for BHV-1 were greater ( < 0.05) on d 1 and 28 for CON vs. NF calves. Humoral immune response to OVA during the 28-d postseparation period from the dam was evaluated in a subset ( = 57) of calves. There was no difference ( = 0.92) in OVA-specific IgG between treatments on d 14 or 28 ( = 0.76); however, OVA-specific IgM was greater ( < 0.05) in CON vs. NF calves on d 28. Results indicate that nose flap devices did not influence feed intake, feed efficiency, or morbidity during the initial postseparation period from the dam. However, preweaning ADG, serum BVDV-1 and BHV-1 titers, and humoral immune response to OVA were decreased in calves that received the nose flap treatment.

Effects of space allowance during transport and duration of mid-journey lairage period on the physiological, behavioural and immunological responses of young calves during and after transport

The effects of space allowance during transportation and duration of a mid-journey lairage period on measurements of stress, injury, dehydration, food restriction and rest in young calves were assessed during and after transport. Groups of calves were transported for two 9-h journeys (at a space allowance of either 0·375 or 0·475 m2 per calf) separated by a mid-journey lairage period of either 1 or 12 h. Non-transported calves were offered milk replacer and drinking water either at the usual times or only at the same times as the transported calves.

During transport, transported calves spent significantly less time lying down and had a greater plasma cortisol concentration than control calves. Under the driving conditions used, increased space allowance was not associated with greater injury or loss of stability. The duration of the mid-journey lairage was not an important factor; the shorter lairage time, giving the calves sufficient time to receive milk replacer but little opportunity to rest, had no major detrimental effects on the variables used to assess welfare. Although there was little evidence that transport affected immunological variables, there was some evidence that it adversely affected the health of the calves post transport.

Models and Methods to Investigate Acute Stress Responses in Cattle

There is a growing appreciation within the livestock industry and throughout society that animal stress is an important issue that must be addressed. With implications for animal health, well-being, and productivity, minimizing animal stress through improved animal management procedures and/or selective breeding is becoming a priority. Effective management of stress, however, depends on the ability to identify and quantify the effects of various stressors and determine if individual or combined stressors have distinct biological effects. Furthermore, it is critical to determine the duration of stress-induced biological effects if we are to understand how stress alters animal production and disease susceptibility. Common stress models used to evaluate both psychological and physical stressors in cattle are reviewed. We identify some of the major gaps in our knowledge regarding responses to specific stressors and propose more integrated methodologies and approaches to measuring these responses. These approaches are based on an increased knowledge of both the metabolic and immune effects of stress. Finally, we speculate on how these findings may impact animal agriculture, as well as the potential application of large animal models to understanding human stress.

Natural variations in the stress and acute phase responses of cattle

Activation of the innate immune system and acute phase response (APR) results in several responses that include fever, metabolic adaptations and changes in behavior. The APR can be modulated by many factors, with stress being the most common. An elevation of stress hormones for a short duration of time can be beneficial. However, elevation of stress hormones repeatedly or for an extended duration of time can be detrimental to the overall health and well-being of animals. The stress and APR responses can also be modulated by naturally-occurring variations, such as breed, gender, and temperament. These three natural variations modulate both of these responses, and can therefore modulate the ability of an animal to recover from a stressor or infection. Understanding that cattle have different immunological responses, based on naturally occurring variations such as these, may be the foundation of new studies on how to effectively manage cattle so that health is optimized and production is benefited.

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the acute phase response to a provocative immune challenge

The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (Ta) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in 4 temperature-controlled environmental chambers. Initially, Ta in the 4 chambers was cycling at thermoneutrality (TN; 18.5°C-23.5°C) for a 1-wk adjustment period, followed by an increase in 2 of the 4 chambers to cycling heat stress (HS; 24°C-38°C) for 2 wk. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), sickness behavior scores (SBSs) were recorded, and blood samples were collected at 0.5-h intervals from -2 to 8 h and again at 24 h relative to LPS challenge at 0 h. Serum was isolated and stored at -80°C until analyzed for cortisol and cytokine concentrations. A breed by Ta interaction (P < 0.001) was observed for RT such that the post-LPS average RT in RO heifers housed at TN was lower than the RT of all other treatment groups (P < 0.001), whereas ANG heifers housed at HS had greater post-LPS average RT than all other treatment groups (P < 0.001). In response to LPS, HS increased SBS after LPS in RO heifers compared to RO heifers housed at TN (P < 0.001), whereas HS decreased SBS after LPS in ANG heifers compared to ANG heifers housed at TN (P = 0.014). The cortisol response to LPS was greater in TN than in HS heifers (P < 0.01) and was also greater in RO than in ANG heifers (P = 0.03). A breed by Ta interaction (P < 0.01) was observed for tumor necrosis factor-α (TNF-α) concentration such that HS increased post-LPS serum concentrations of TNF-α in ANG heifers compared to ANG heifers housed at TN (P = 0.041), whereas HS decreased post-LPS concentrations of TNF-α in RO heifers compared to RO heifers housed at TN (P = 0.008). A tendency (P < 0.06) was observed for a breed by Ta interaction for IL-6 concentrations such that RO heifers had greater post-LPS concentrations of IL-6 than ANG heifers when housed at HS (P = 0.020). A breed by Ta interaction was observed for interferon-γ (IFN-γ; P < 0.01) concentrations such that HS decreased post-LPS concentrations of IFN-γ in ANG heifers compared to ANG heifers housed at TN (P < 0.001), and HS increased post-LPS concentrations of IFN-γ in RO heifers compared to RO heifers housed at TN (P = 0.017). These data indicate differences in the acute phase response between the heat-tolerant RO and heat-sensitive ANG heifers under different Ta which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds.

The effect of road transport in comparison to a novel environment on the physiological, metabolic and behavioural responses of bulls

The objective was to investigate the effect of 18 h road transport with a 12h mid-journey rest period in comparison to the exposure of bulls to a novel environment on physiological, metabolic and behavioural responses of beef bulls. Thirty Charolais sired crossbred beef bulls (mean 486.0, s.d. 57.0 kg) were assigned by live weight to one of the two treatments, transport (T) (9h+9h) (n=15) and not-transported (NT) (n=15) on day 0. The bulls were transported at a spatial allowance of 1.3m(2)/animal by road for 9h, unloaded and rested for a 12h rest period, re-loaded and transported for a further 9h journey by road followed by a 2h rest period on the transporter, then unloaded and rested in a lairage for 24h with access to hay and water. Plasma albumin and urea concentrations increased (P<0.05) after the first 9h journey with values returning to baseline at the end of the 24h recovery period. There was a transient increase in haematocrit% in T and NT at sampling time points corresponding to the completion of the first 9h journey. Bulls spent longer time lying (P<0.05) during the first 9h journey compared with the percentage time spent lying during the second 9h journey. Differences in live weight, behaviour, and some blood variables show that transport is more stressful for bulls than being subjected to a novel environment and management, and while some biological variables returned to baseline values, others require a longer time (plasma haptoglobin, total protein, glucose and NEFA concentrations). Thus, the effective recovery of bulls exposed to an 18 h transport journey by road would suggest that a rest period of at least 24h with access to feed and water is required before further transport.

Growth and Development Symposium: Impacts of inflammation on cattle growth and carcass merit

Inflammation caused by bovine respiratory disease (BRD) continues to be one of the greatest challenges facing beef cattle producers and feedlot managers. Inflammation decreases DMI, ADG, and G:F in feedlot calves, decreasing growth rate and increasing days on feed, which results in economic losses during the feeding period. During the past decade, marketing of feedlot animals has changed from selling cattle on a live basis to a grid-based marketing system. When cattle are marketed on a live basis, the economic effects of BRD stop at increased health cost and decreased feedlot performance, carcass weight, and death loss. However, when cattle are marketed in a grid-based system, inflammation has the potential to also affect carcass cutability and quality. The effects of inflammation on feedlot cattle in regards to performance are well understood; however, specific effects on cattle growth and ultimately carcass merit are not as well described. Recent studies in feedlot cattle have indicated that the incidence of BRD decreases both HCW and marbling; however, mechanisms are not understood. Research in other species has demonstrated that during the acute phase response, pro-inflammatory cytokines promote skeletal muscle catabolism to supply AA and energy substrates for immune tissues. Further, during this early immune response, the liver changes its metabolic priorities to the production of acute phase proteins for use in host defense. Together these dramatic shifts in systemic metabolism may explain the detrimental effects on performance and carcass traits commonly associated with BRD in feedlot calves. Moreover, recent studies relative to human health have revealed complex multilevel interactions between the metabolic and immune systems, and highlighted inflammation as being a significant contributor to major metabolic diseases. The objective of this paper is to review data to help explain the economical and physiological effects of inflammation on cattle growth and carcass merit.

The effects of fermented soybean meal on immunophysiological and stress-related parameters in Holstein calves after weaning

The present experiment was conducted to investigate the effects of partial substitution of soybean meal (SBM) with fermented SBM (FSBM) on immunophysiological and stress-related parameters in Holstein calves after weaning. Eighteen Holstein calves were randomly assigned to receive either SBM or FSBM (5% of SBM was replaced with FSBM) calf starter and calves were weaned at 42 d of age. It was noted that FSBM contained a lower content of trypsin inhibitor but higher crude protein, amino acids, and small-sized peptides than those of SBM. The group fed FSBM calf starter significantly increased body weight gain and intakes of both feed and milk, when compared with those fed SBM calf starter at 4 wk of age. Calves fed the FSBM calf starter had significantly lower fecal scores than those fed the SBM calf starter during both pre- and postweaning periods. Calves also had better health scores when fed the FSBM calf starter than those fed SBM during the preweaning period. Weaning challenge significantly increased proinflammatory cytokines, tumor necrosis factor α, IL-1β, and IL-6 levels at 1d postweaning (DPW). The TNF-α and IL-6 levels of the SBM group were significantly higher compared with those of the FSBM group at 3 DPW. Acute phase proteins (serum amyloid A and haptoglobin) in the serum were increased after weaning. Concentrations of serum amyloid A and haptoglobin in calves fed FSBM calf starter were significantly lower than those fed the SBM calf starter at 3 and 5 DPW, respectively. The concentration of cortisol was significantly lower in the FSBM group than that of the SBM group at 3 DPW. Weaning stress did not cause drastic changes in the total serum immunoglobulin levels and composition of peripheral lymphocytes. Our results indicate that FSBM may not only improve growth performance, feed intake, and health conditions during the preweaning period, but also alleviate stress responses, which was indicated by reduced induction of stress hormone, proinflammatory cytokines, and acute phase proteins in Holstein calves after weaning.

Stress significantly increases mortality following a secondary bacterial respiratory infection

A variety of mechanisms contribute to the viral-bacterial synergy which results in fatal secondary bacterial respiratory infections. Epidemiological investigations have implicated physical and psychological stressors as factors contributing to the incidence and severity of respiratory infections and psychological stress alters host responses to experimental viral respiratory infections. The effect of stress on secondary bacterial respiratory infections has not, however, been investigated. A natural model of secondary bacterial respiratory infection in naive calves was used to determine if weaning and maternal separation (WMS) significantly altered mortality when compared to calves pre-adapted (PA) to this psychological stressor. Following weaning, calves were challenged with Mannheimia haemolytica four days after a primary bovine herpesvirus-1 (BHV-1) respiratory infection. Mortality doubled in WMS calves when compared to calves pre-adapted to weaning for two weeks prior to the viral respiratory infection. Similar results were observed in two independent experiments and fatal viral-bacterial synergy did not extend beyond the time of viral shedding. Virus shedding did not differ significantly between treatment groups but innate immune responses during viral infection, including IFN-γ secretion, the acute-phase inflammatory response, CD14 expression, and LPS-induced TNFα production, were significantly greater in WMS versus PA calves. These observations demonstrate that weaning and maternal separation at the time of a primary BHV-1 respiratory infection increased innate immune responses that correlated significantly with mortality following a secondary bacterial respiratory infection.

Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge

Our primary objective of this experiment was to evaluate potential genetic differences between two diverse Bos taurus breeds [Angus (AG) and Romosinuano (RO)] in response to an endotoxin challenge. Eighteen steers (n = 9 steers/breed; 299.4 ± 5.2 kg BW) were acclimated to environmentally controlled chambers maintained at thermoneutrality (19.7 °C) and then fitted with indwelling jugular catheters and rectal temperature (RT) recording devices 1 d before the endotoxin challenge. The next day, blood samples were collected at 30-min intervals from -2 to 8 h, and RT was measured continuously at 1-min intervals throughout the study. At time 0, all steers received an intravenous bolus injection of lipopolysaccharide (LPS; 2.5 μg/kg BW). Serum samples were stored at -80 °C until analyzed for cortisol, proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, and interferon gamma (IFN-γ)], and acute phase proteins (serum amyloid A, acid soluble protein, ceruloplasmin, and α-acid glycoprotein). Rectal temperatures increased in both breeds within 1 h after LPS, with RO producing a greater increase in RT than AG steers (P < 0.001). Serum cortisol and TNF-α increased (P < 0.01) in both breeds within 1 h after the LPS challenge. For cortisol, an overall breed effect (P < 0.02) was detected, such that AG steers had a higher cortisol response than RO steers. A breed × time interaction (P < 0.01) was observed for TNF-α, such that the response was delayed and extended in the RO steers compared with the AG steers. At 2 and 2.5 h after LPS, TNF-α concentrations were greater (P < 0.03) in RO steers than in AG steers. For IL-1β, a breed × time interaction (P < 0.04) was also observed. At 3 h after LPS, IL-1β concentrations were greater (P < 0.01) in RO steers than in AG steers. Serum IL-6 and IFN-γ increased (P < 0.01) in a similar manner in both groups after the LPS challenge. These data show differences in the innate immune response between two diverse Bos taurus breeds which may provide insight about differences observed in productivity, heat tolerance, disease resistance, and longevity among cattle breeds.

The effect of transport by road and sea on physiology, immunity and behaviour of beef cattle

The objective of the study was to investigate the physiological, haematological and immunological responses of weanling heifers transported from Ireland to a feedlot in Spain, and of weanling bulls transported from Ireland to a feedlot in Italy. Physiological variables (including interferon-γ production, cortisol, protein, urea, white blood cell numbers and differentials, and acute phase proteins (haptoglobin and fibrinogen) were used to evaluate the welfare status of animals, before, during and after the respective transport journeys. Age-matched control animals were blood sampled for the same measurements at times corresponding to the transported animals that were retained in Ireland. Heifers transported to Spain lost 7.6% of their initial live weight during the sea crossing to France. However, by the time of their arrival in Spain they had regained 3.3% of their initial live weight and had fully recovered to their pre-transport live weight values within 6 days of arriving in Spain. Weanling bulls lost 7.0% of their live weight during the sea crossing from Ireland to France. The live weight loss in control animals ranged from 1% to 2% during the same period. The percentage of time that bulls spent lying was 63.5% for the sea journey and 35.4% for the journey from the French lairage to the Italian feedlot. The average daily gain (kg) of transported animals was greater (P ≤ 0.05) than control animals from day 11 to 38 (Spain) and day 11 to 40 (Italy), respectively. While transient changes in physiological, haematological and immunological variables were found in the transported and control animals relative to baseline levels, the values were within the normal physiological range for the age and weight of animals involved. Physiological measurements made after the road and sea journeys indicated that the 24h rest in the lairage, with hay and water freely available, allowed animals to recover substantially.