Autumn Ready – Weaning, housing, trade & BEEP-S 

Weaning, housing and trade are integral components of the beef sector subjecting both dams and their calves to stressors. This article will firstly review the scientific background behind stress and how it influences disease occurrence then examining in more detail key elements with consideration in each case how farmers can be best advised to minimise their negative impact.

Stress and Bovine Respiratory Disease (BRD)

Stressors influence an immunity mechanism which includes activation of the hypothalamus-pituitary and sympathoadrenal axes resulting in an increase in cortisol and adrenaline respectively1.  

Stressors negatively impact cell mediated and humoral immunity resulting in increased susceptibility to disease notably BRD in weanlings. Despite a large body of research focusing on this disease entity, BRD is the most frequently diagnosed cause of mortality in cattle from six months to one year of age with 39.8% diagnosed by post-mortem in 2020 in Ireland (Figure 1)2. Respiratory infection was also the most frequently diagnosed condition in calves from one to five months and cattle over 12 months of age on post-mortem at 33.4% and 17.5 % respectively2. Substantial economic implications of BRD are not only restricted to treatment costs and mortality, but also significant long-term impacts. Consequences of the disease can manifest later in life with decreased feed conversion efficiency and decreased daily weight gain. These have negative effects on carcass composition and quality traits. It can take 59 days longer to finish cattle who present with obvious clinical signs of pneumonia3 while for subclinical cases of BRD it has been reported that there is a decrease of between 0.125-0.35 kg average daily gain4. The significant prevalence of lung lesions detected in abattoirs highlight the gravity of both clinical and subclinical disease, with one study reporting that 64% of animals had at least one lung lesion at slaughter5. 

BRD has a multifactorial aetiology which culminates from variable interactions between the host, pathogens and environment resulting in a complex range of pulmonary lesions. There is a seasonal peak of cases from September to February6. The All-Island Disease Surveillance Report for 2020 stated the most common pathogenic agents associated with BRD and detected on post-mortem were Dictyocaulus viviparus, M. haemolytica, H. somni, P. multocida, respiratory syncytial virus and M. bovis7. Viruses can interfere with lung defense mechanisms and predispose calves to bacterial colonisation of the lower respiratory tract. Synergistic interactions of bacteria and viruses can result in more severe outcomes in these concurrent infections. The principal bacterial pathogen implicated in BRD in weanlings in 2020 was M. haemolytica (17.4%) figure 27. M. haemolytica is a commensal organism of the nasopharynx and tonsillar crypts. Stressed animals can succumb to infection when the opportunistic pathogen invades the lower respiratory tract in animals resulting in a fibrinonecrotic pneumonia8. Recent findings suggest that this is potentially due to bacterial invasion of, and rapid proliferation within, the mucosal epithelium of the respiratory tract9. 

In order to redress the balance in favour of the animals, vaccines may be used to elevate immunity levels prior to the stress event(s). Bovilis Bovipast RSP provides the broadest protection available on the market against M. haemolytica as it is the only cattle vaccine licensed to protect against both serotypes A1 and A6. Bovilis Bovipast RSP reduces infection, mortality, clinical signs, lung lesions and bacterial invasion of the lung caused by serotypes A1 and A6. One study of commingled beef bulls demonstrated that M.haemolytica serotype A6 accounted for 63% of isolates within 40 days of arrival at a fattening facility10. 

Figure 1: Conditions most frequently diagnosed on post-mortem examinations of weanlings (6–12 months old) in 2020 (n=377)7 
Figure 2. Percentage of general specific organisms detected in BRD on post-mortem examination of weanlings (6-12 months old), (n=457)7 

Weaning

Weaning is considered a major source of stress for calves as it involves removal from the dam, dietary changes and potentially a new social environment. Weaning is characterised by both behavioural alterations and changes in hormonal mediators of stress. Calves exhibit distress signals after separation particularly when abruptly weaned. They can exhibit increased vocalisation, activity and reduced feed intake. Abrupt weaning at housing results in transient neutrophilia with temporary decrease in phagocytosing neutrophils, a temporary decrease in lymphocyte subsets, most notably of ỿδ lymphocytes11 and an increase of the acute phase protein fibrinogen12. 

Husbandry practices such as castration, dehorning and dosing coupled with changes in weather can exacerbate the stress response associated with weaning. It is advised to castrate weanlings four weeks prior to, or two weeks post, weaning. Strategic anthelmintic program is advised during the first grazing season. A convenient option for dosing weanlings greater than 100 kg is Repidose, a pulsatile release intraruminal device which delivers a programmed therapeutic anthelmintic dosing regimen during the grazing season. 

To mitigate stress, it is advised to introduce concentrates to calves four weeks prior to weaning, gradually increasing to an allowance of 1 kg/day at weaning. Feeding meal with appropriate minerals and vitamins pre-weaning is a feature of the Beef Environmental Efficiency Programme- Suckler (BEEP-S) in association with post-weaning meal feeding for two weeks as one of the voluntary actions13. BEEP-S also has a voluntary vaccination action which involves implementing a vaccination programme for respiratory diseases.  

Creep grazing could be considered to aid in reducing stress as it will enable calves to graze away from the cows and reduce the maternal bond. Providing fence-line contact for cows and calves is another method to reduce stress at weaning which can be incorporated with anti-suckling devices. This two-stage weaning approach closely simulates natural weaning process and calves are less distressed than abruptly weaned calves14.  

Housing 

Weaning, castration and vaccination are recommended in advance of housing where possible. It is essential that housing promotes good health and welfare. Good ventilation is key to the health of weanlings as it decreases airborne pathogen concentrations along with decreasing ammonia levels, dust and optimising the humidity of the shed. Natural ventilation is the preferable approach. Overcrowding should be avoided by ensuring animals have adequate space allowance. Animals less than 275 kg and greater than 275 kg housed in slatted sheds are recommended to have 1.2-2.5 m2 allowance and 2.0- 2.5 m2 respectively. Feed space allowance of 225-300 mm per head is recommended for weanlings fed ad-lib roughage15. Laser measuring devices provide a convenient way for vets to assess whether farmers are complying with these guidelines. Ensure that all animals have access at any one time to an ample supply of fresh clean water. Minimum air space for animals greater than 150kg is 15m3. It is advisable to delay housing for a period post-weaning and house cattle on a dry day. Ideally separate housing should be available to isolate sick animals when identified. Using a compass to determine if the long axis of the shed is at right angles to the south-west (the seat of the prevailing wind) maximises ventilation efficiency. Finally adequate light, of at least 100 lux, in all areas (which can be measured with a smart phone app) ensures clinical cases are picked up earlier, improving therapeutic success. After housing dose animals with an appropriate anthelminthic and consider fluke control if this is relevant to the animals’ risk profile. 

Trade

Selling or buying inevitably involves transportation of weanlings and potentially commingling animals from various sources. Transportation is a well-recognised stressor to weanlings. These stressors again result in neutrophilia, increased serum cortisol concentration, increased acute phase proteins and decreased lymphocytes, negatively impacting the defence mechanisms of the weanlings16. It is recommended to minimise commingling and quarantine newly purchased animals for at least 4 weeks in a separate shed or, weather permitting, a well sheltered pasture with double fencing. Mixing weanlings from different sources disrupts existing hierarchies and poses a BRD risk as cattle are exposed to pathogenic agents. A vaccination programme for bought-in weanlings is advised. Vaccination with an intranasal live vaccine could be considered to provide fast protection before commingling. Any bought in animals should be monitored closely for characteristic clinical signs. Detecting clinical respiratory signs by observation has limitations in relation to subclinical cases. For successful intervention identifying animals in the early stage and subsequently treating for the adequate duration is vital17. 

BEEP-S Overview  

If your clients are enrolled in the BEEP-S scheme there are a few important actions they must fulfil in order to correctly receive the payments. The Beef Environmental Efficiency Programme – Suckler (BEEP- S) is a voluntary programme for suckler herds. The objective of the programme is to further increase economic and environmental efficiency in the suckler herd though improvement in the quantity and quality of performance data that are collected13. BEEP-S comprises of one mandatory action and two voluntary actions. Action 1 is compulsory which involves weighing the unweaned eligible live calf and dam separately. These weights must be submitted to ICBF. Action 2 is an optional choice of vaccination or meal feeding. These measures will improve the health and welfare of the calves by reducing the stress at weaning time and reduce the incidence of BRD. Meal must be introduced for a period of 4 weeks pre-weaning and 2 weeks post-weaning. The vaccination option involves implementing a vaccination programme for respiratory disease. To qualify for the vaccination payment of the programme the applicants must choose one of two options for vaccination. Vaccination receipts must be retained and dates of vaccination recorded. Action 3 is an optional action of faecal egg testing in cows to detect liver and rumen fluke. 

There is on-going research to reduce incidence of BRD in beef animals including breeding for resistance, evaluation of gene expression by transcriptomics of cattle at arrival18, supplementing weanlings with oxidative compounds19 and the use of animal health technology on arrival20. Nevertheless, the focus in practice remains on reducing stress at weaning, housing and trade. Minimising stress will enable weanlings to readily respond and adapt in a timely manner to stressors they are exposed to and ultimately influence disease outcome. 

This month is ideal for private veterinary practitioners (PVP) to engage with suckler farmers to advise good pre- and post-weaning management practices to help mitigate risk factors associated with stress and BRD in this age group. PVPs can play a pivotal role in selecting a suitable vaccination programme to enhance acquired immunity for each suckler herd subject to the time-frame available before the risk period. PVPs are also instrumental in educating farmers that prophylactic and metaphylactic use of antimicrobials is limited since January 2022 to address “One Health, One Welfare” challenges of antimicrobial resistance (AMR).  

Disease prevention strategies are key to address the global public health threat of AMR and to reduce the incidence of BRD in weanlings. Regarding clinical cases PVPs play a pivotal role in correct diagnosis and in judicious use of antimicrobials. By actively engaging with your clients this month to discuss the multifaceted approach to weaning, housing and trade you will help to optimise both health and welfare of weanlings in the autumn period.  

References:  

  1. Hickey, M.C, Drennan, M, Earley, B. The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocytes, acute-phase proteins and in vitro interferon-gamma production. Journal of Animal Science, 2003, 81:2847-2855 
  1. All- Island Animal Disease Surveillance Report, 2020. Department of Agriculture, Food and Marine of Ireland, Agri-Food and Bioscience Institute and, Animal Health Ireland.  
  1. Bareille, N, Seegers, H, Denis, G, Quillet, J.M, Assie, S. Impact of respiratory disorders in young bulls during their fattening period on performance and profitability. Recontres autour des Recherches sur les Ruminants, 2008, 11: 77-80 
  1. Production Significance of Bovine Respiratory Disease Lesions in Slaughtered Beef Cattle. Fernández, M., del Carmen Ferreras, M., Giráldez, F.J., Benavides, J. Pérez, V. Animals 2020, 10 1770  
  1. Gagliazzo, L. et al., Impact of bovine respiratory disease on lung lesions, slaughter performance and antimicrobial usage in French beef cattle finished in North-Eastern Italy. Italian Journal of Animal Science, 2018, 17: 1065-1069 
  1. Murray, G.M. et al. Pathogens, patterns of pneumonia, and epidemiologic risk factors associated with respiratory disease in recently weaned cattle in Ireland. Journal of Veterinary Diagnostic Investigation, 2017, 29(1): 20-34 
  1. All- Island Animal Disease Surveillance Report, 2020. Department of Agriculture, Food and Marine of Ireland, Agri-Food and Bioscience Institute and, Animal Health Ireland.  
  1. Clawson, M.L, Murray R.W. Pathogen variation across time and space: sequencing to characterize Mannheimia haemolytica diversity. Animal Health Research Reviews, 2014, 15(2):169-171 
  1. Cozens, D, Sutherland, E, Lauder, M, Taylor, G, Berry, C.C, Davies, R.L. Pathogenic Mannheimia haemolytica invades differentiated bovine airway epithelial cells. Infection and Immunity. 2019, 87(6):e00078-19  
  1. Timsit, E, Christensen, H, Bareille, N, Seegers, H, Bisgaard, M, Assie, S. Transmission dynamics of Mannhaemia haemolytica in newly received beef bulls at fattening operations Veterinary Microbiology, Elsevier, 2013, 161 (3-4): 295-304. 
  1. Lynch E.M, Earley B, McGee M, Doyle S. Effect of abrupt weaning at housing on leukocyte distribution, functional activity of neutrophils, and acute phase protein response of beef calves. BMC Vet Research, 2010, 22;6:39 
  1. Hickey M.C, Drennan M, Earley B. The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocytes, acute-phase proteins and in vitro interferon-gamma production. Journal of Animal Science, 2003, 81;11:2847-55 
  1. Beef Environmental Efficiency Programme Sucklers (BEEP-S) as part of the Beef Sector Efficiency Programme. Department of Agriculture, Food and the Marine. Available at: gov.ie – Beef Environmental Efficiency Programme Sucklers (BEEP-S) as part of the Beef Sector Efficiency Programme (www.gov.ie). Accessed: June 2022 
  1. Haley D.B, Bailey D.W, Stookey J.M. The effects of weaning beef calves in two stages on their behavior and growth rate. Journal of Animal Science, 2005, 83;9:2205-14 
  1. Ryan, T. Lenehan, J.J. Winter accommodation for beef animals. Section 8. Teagasc, the Agriculture and Food Development Authority. Accessed: June 2022 
  1. Arthington, J.D, Eicher, S.D, Kunkle, W.E, Martin, F.G. Effect of transportation and commingling on the acute-phase protein response, growth, and feed intake of newly weaned beef calves. Journal of Animal Science, 2003, 81;5:1120-1125  
  1. Lorenz, I, Earley, B, Gilmore, J, Hogan, I, Kennedy, E, More, S.J. Calf health from birth to weaning. III. Housing and management of calf pneumonia. Irish Veterinary Journal. 2011, 64;1:14 
  1. Scott M.A, Woolums A.R, Swiderski C.E, Thompson A.C, Perkins A.D, Nanduri B, Karisch B.B, Goehl D.R. Use of nCounter mRNA profiling to identify at-arrival gene expression patterns for predicting bovine respiratory disease in beef cattle. BMC Vet Research, 2022, 23;18:77 
  1. Engler P, Desguerets C, Benarbia M.E.A, Mallem Y. Supplementing young cattle with a rumen-protected grape extract around vaccination increases humoral response and antioxidant defenses. Veterinary Animal Science, 2022 4;15:100232 
  1. Nickell J.S, Hutcheson J.P, Renter D.G, Amrine D.A. Comparison of a traditional bovine respiratory disease control regimen with a targeted program based upon individualized risk predictions generated by the Whisper on Arrival technology. Translational Animal Science, 2021, 6;5:2