Farm animal welfare: managing pain assessment in cattle

Pain management in cattle has become an increasingly important aspect of livestock production, driven by advancements in veterinary medicine and growing societal concerns about farm animal welfare. Over the past few years, significant progress has been made in understanding and managing pain in livestock, particularly in cattle. Pain is a critical component of animal well-being that must be considered at various stages of livestock production systems. Effective pain management involves adapting strategies to the specific needs of animals, considering factors such as species, breed, age, behaviour, the type of procedure causing pain, the extent of tissue damage, and the intensity of the pain triggered.

Prefer to listen to this article? Click the play button below and enjoy our podcast!

Regulatory and economic considerations also play a role in pain management decisions. Despite initial scepticism, many breeders have observed clear improvements in their animals' conditions after systematically administering non-steroidal anti-inflammatory drugs (NSAIDs) during surgeries like displaced abomasum or caesarean sections. Although cattle may not show obvious signs of pain, research over the last 15 years has identified several pain indicators in cattle, categorized into postural and behavioural indicators, physiological indicators, and zootechnical indicators. Early management of pain not only reduces the duration of analgesic treatments but also provides long-term benefits, such as reduced subsequent morbidity and mortality.

Physiological Consequences of Pain

The physiological consequences of pain in cattle are multifaceted and can significantly impact their health and productivity. Unmanaged pain in cattle induces stress and triggers a cascade of physiological disruptions that negatively affect overall health. Pain stimulates the release of stress hormones such as glucocorticoids and activates the sympathetic nervous system. This can lead to metabolic disturbances (like acidosis and hypoxemia), immunosuppression, impaired healing, and even death in severe cases. Pain also affects vital functions, including cardiovascular, respiratory, gastrointestinal, urinary, and nervous systems.

For instance, pain can increase heart rate, blood pressure, and cardiac workload, leading to a risk of arrhythmias. It can also cause respiratory issues like atelectasis and a risk of food aspiration, gastrointestinal problems like ileus, and urinary issues like bladder retention. Metabolically, pain increases oxygen consumption and can lead to hyperglycaemia, while also depleting muscle, fat, and glucose reserves.

Chronic pain can lead to hyperalgesia and allodynia, where animals become more sensitive to pain, further compromising their well-being and productivity. In dairy cows, pain can reduce milk production due to decreased food intake and altered time budgets for different activities.

Main Principles of Analgesia

Effective pain management in cattle involves several key principles:

• Multimodal Analgesia: Pain is a complex phenomenon involving numerous relays, receptors, and neurotransmitters. Using a combination of analgesic drugs rather than a single drug can optimize pain management. For example, combining local anaesthesia with NSAIDs has shown superior analgesic effects in procedures like dehorning and castration.
• Early Initiation: Early administration of analgesics is crucial to limit peripheral and central sensitization phenomena that can lead to exaggerated pain conditions. Delayed analgesia can reduce the efficacy of treatments and increase the risk of chronic pain.
• Appropriate for the Level of Pain: The choice of analgesic treatment must be tailored to the intensity and duration of the pain. Pain is classified into three levels:
  • Level I (mild): managed with NSAIDs alone.
  • Level II (moderate): requires NSAIDs + weak opioids or local anesthesia (requires the intervention of a veterinarian).
  • Level III (severe): requires full multimodal protocols including NSAIDs, opioids, nerve blocks, and sometimes sedation (requires the intervention of a veterinarian)

• Continuous Assessment: Pain management must be maintained as long as necessary, with continuous postoperative assessment of pain to adjust treatments accordingly.

NSAIDs (non-steroidal anti-inflammatory drugs) are the cornerstone of analgesia in cattle, offering both central and peripheral action with minimal handling complexity for farmers. Other options include local anesthetics, alpha2-agonists, dissociative anesthetics, and opioids (under cascade use).

How can pain be detected to ensure farm animals welfare?

Detecting pain in cattle can be challenging due to their stoic nature and subtle signs of discomfort. Key indicators of pain include:

• Postural Indicators: Arching the back, crossing over the front legs, spreading the back legs, and prolonged standing or lying positions.
• Behavioural Indicators: Lameness, trampling, kicking, reduced feeding behaviour, vocalizations, grinding teeth (bruxism), changes in facial expression and avoidance behaviours.
• Physiological Indicators: Increased heart and respiratory rates, bladder retention and reduced movement.

Behavioural observation remains the most practical method for detecting pain in cattle. Tools such as the Cow Pain Scale and the UNESP-Botucatu Grid help to quantify pain based on behavioural changes, thus aiding the decision to initiate analgesia.

Economic Benefit of Pain Management in Cattle

Effective pain management in cattle offers both clinical and economic benefits. Studies have shown that analgesic treatments can improve average daily gain (ADG) in cattle undergoing procedures like castration and dehorning. For example, administering NSAIDs before castration has been shown to reduce the decrease in ADG and improve overall health outcomes. In the case of caesarean sections, cows treated with NSAIDs spent more time lying down and showed better maternal behaviour, leading to improved calf health and passive immunity transfer. Analgesia during illness, such as arthritis and mastitis, has also shown benefits in improving cure rates, and lowering culling rates.

Economically, effective pain management can reduce the risk of respiratory disorders, improve reproductive performance, and increase milk production. For instance, treating lameness early with NSAIDs and curative trimming has been shown to improve cure rates and overall productivity.

In conclusion, pain management in cattle is a multifaceted issue that requires a comprehensive understanding of pain indicators, appropriate analgesic strategies, and continuous assessment. By addressing pain effectively, livestock producers can improve farm animal welfare, enhance productivity, and achieve economic benefits.

Key Messages

• Pain Must Be Addressed: Pain management is not just a critical component of animal well-being, it also helps to increase animal  productivity. Early and appropriate analgesia can significantly improve clinical outcomes and economic benefits.
• It is important to know the signs of pain in cattle: Cattle show pain in subtle ways. Careful observation of behaviour and posture is essential for timely intervention.
• Beyond ethical concerns, pain has economic consequences: From milk production to reproduction and longevity, pain negatively affects performance. Managing it effectively improves productivity, reduce morbidity and mortality, and enhance overall herd health and profitability.

The content of this article was developed using the e-book Pain Management in Cattle as a reference.

References

de Oliveira, F. A., Luna, S. P. L., do Amaral, J. B., Rodrigues, K. A., Sant'Anna, A. C., Daolio, M., & Brondani, J. T. (2014). Validation of the UNESP-Botucatu unidimensional composite pain scale for assessing postoperative pain in cattle. BMC veterinary research, 10, 1-14.

Gleerup, K. B., Andersen, P. H., Munksgaard, L., & Forkman, B. (2015). Pain evaluation in dairy cattle. Applied Animal Behaviour Science, 171, 25-32.

Gleerup, K. B., Forkman, B., Otten, N. D., Munksgaard, L., & Andersen, P. H. (2017). Identifying pain behaviors in dairy cattle. WCDS Adv Dairy Technol, 29, 231-239.

Guatteo R. (2022), Pain management in cattle: why, how ?. Ceva Santé animale.