Dr Eva Mainau Brunsó and Elke Abbeloos
Labour pain is inherent to the calving process and is, like in women, probably not completely avoidable. However, by having domesticated cattle - both physically and genetically - we have to accept our responsibility with regard to their health and welfare. As specified in the 5 freedoms of the Animal Welfare Council, we need to diagnose, prevent and treat pain as early as possible.
Breeding programs and domestication have resulted in calves that are relatively large compared to their dams, leading to a greater risk of dystocia than in other mammals. However, the evolutionary predator-avoidance instincts and stoical nature of cattle may mask pain1.
The 5 freedoms of the Animal Welfare Council.
- Freedom from hunger or thirst by ready access to fresh water and a diet to maintain full health and vigour.
- Freedom from discomfort by providing an appropriate environment including shelter and a comfortable resting area.
- Freedom from pain, injury or disease by prevention or rapid diagnosis and treatment.
- Freedom to express (most) normal behaviour by providing sufficient space, proper facilities and company of the animal’s own kind.
- Freedom from fear and distress by ensuring conditions and treatment which avoid mental suffering.
Is the cow in pain?
Labour pain ranks amongst the most intense pains recorded in comparison to other pain syndromes, and it has received a great deal of scientific interest, particularly in women giving birth. In 1853, Queen Victoria received analgesia in the form of chloroform at the delivery of her 8th child. The development of safe and efficacious analgesic techniques, as well as the social acceptance that painful childbirth is unnecessary, led to considerable progresses in the field. More importantly, the progress was associated with a dramatic reduction in maternal and foetal mortality in developed countries2. More recent research focuses on mid- and long term outcomes, such as faster recovery and chronic pain and depression. Researchers discovered that the level of pain at delivery and not the mode of delivery is the major risk factor for long-term pain and depression in women2.
The parturition process and pathways of pain in cows are no different from those in humans. Scientists around the globe, therefore, accept the fact that also cows experience pain in a similar manner. However, since self-reporting in humans is the golden standard for pain assessment, there is a need for research based direct and indirect indicators of pain in order to define when and how much cows are in pain.
Physiological indicators
Physiological parameters such as cortisol and acute phase proteins have been used to identify pain in cows around parturition. For instance, vasopressin levels were higher in heifers that needed assistance. Haptoglobin has been found to be higher in cows with uterine torsion3. Acute phase proteins are indirect measures of pain since they indicate trauma and inflammation, which is usually accompanied with pain.4
Behavioural indicators
Behavioural indicators are usually more sensitive in identifying small differences in pain levels than physiological indicators. Increased restlessness is often a sign of di scomfort, but in the case of parturition could also be interpreted as normal calving behaviour. Certain behaviour is more commonly observed in cows with dystocia, such as a more frequent change of position beginning 48 hours before calving5 and increased frequencies of rubbing against the wall, urinating, scraping the floor6, kicking, self-grooming and head turning 7,8. Some of these indicators are already visible 24h before the (difficult) calving takes place.
Economical more relevant is the change in feeding behaviour in dystocic cows. Feed intake decreases during the final week of gestation in all cows, possibly because the large calf reduces space in the abdomen. However, cows with dystocia eat 2.6 kg less during the 48h before calving compared to normally calving cows. It also takes longer for them to have their first meal after calving 5.
Feed intake and energy metabolism are crucial during the transition period. The recognition and management of pain around calving will not only contribute to animal welfare but will also help the cow to have a successful transition to optimal milk production. A difficult or prolonged calving is associated with lower milk production and fertility in the subsequent period, as well as higher risk of culling 1. This association may partly be explained by a lower feed intake due to pain and inflammation after a difficult calving, increasing the negative energy balance of the cow and all the consequences that may have.
Should calving pain be addressed?
Some people may argue that birth is a natural process and therefore does not need pain control. However, genetic selection has led to an increased risk of dystocia, while modern husbandry management does not allow the cow to express certain behaviour that would lead to natural analgesia. The cow has an admirable mechanism of increasing the nociceptive threshold at the end of pregnancy and during parturition, through the release of endogenous opioids9. The ingestion of amniotic fluids by the cow enhances the opioid effect, providing analgesia for the cow after birth10. Early removal of the calf for hygiene and management reasons will deprive the cow of optimal natural pain control. But even if the calf is not removed, amniotic fluids have often dried in case of prolonged calvings, so that cows that need this natural painkiller the most often benefit least.
The benefit of NSAIDS
Nonsteroidal anti-inflammatory drugs may help alleviate the impact of the inflammation and presumed pain associated with parturition. Huxley and Whay11 reported that 66% of veterinarians in the UK use NSAIDs after dystocia. Veterinarians generally agree with the fact that cows with dystocia suffer from severe pain and would benefit from pain management. Unfortunately, the majority of the calvings – whether assisted or not is attended only by the farmer. However, the awareness of pain and pain relief seems to be much lower in farmers than in veterinary practitioners12,13.
Conclusion
Both genetic selection and management procedures have led to a more painful birth process in domestic cows compared to their wild ancestors. With the domestication and farming of cattle, we should take our responsibility regarding animal health and welfare. Freedom of pain is one of the main pillars of good animal welfare. The farmer’s awareness should be raised concerning the need for pain relief, in particular during difficult calving.
