calves 
cross suckling

Cross-Sucking in Group Housed Calves Separated from Their Mothers

by Ryan Wennekamp

What is Cross-Sucking Behaviour?

Young calves who are raised together in groups or in individual pens often exhibit an abnormal behaviour called cross-sucking. Cross-sucking is defined as one calf sucking the ear, mouth, scrotum, prepuce, tail, udder area or navel of another calf (Lidfors 1993). This type of behaviour may also lead to extensive urine drinking or injurious cross-sucking. Cross-sucking is considered to be abnormal because it has not been reported to occur in systems where the cow and calf are kept together, this indicates that this cross-sucking is due to present management practices which are detrimental to the welfare of the calf. The most frequent types of cross-sucking is one animal sucking the ears or mouth of another animal (Lidfors 1993). Two possible reasons for this is that the mouth and ears are the most convenient area to suck, or that they may still have milk on them. Another area that is most commonly sucked is the scrotal area which is the area where the calf would find the udder on its mother (Lidfors 1993).

Causes of Cross-Sucking

Cross-sucking is most often seen in group housed dairy or veal calves, who are not allowed to suckle their mothers. The frequency of this behaviour is highest shortly after feeding, and is especially prevalent in calves who are bucket fed rather than artificial teat-fed. However, bucket feeding is favoured by most producers because there is no conclusive data that it has a negative effect on performance, and because of the simplicity and ease of cleaning.

The sucking stimulus in calves is thought by many researchers to be stimulated by the ingestion of milk. Studies done by De Passille et al (1992), and Hammell et al (1988) both show that drinking milk via a bucket stimulated sucking and butting of a dry teat. The actual reason for this is unknown, however, possible explanations given by De Passille et al (1992) are that there is a factor in milk (biologically active peptides are known to exist in milk) which stimulates a neural message at the stomach level. This factor could act as a neurotransmitter and stimulate the sucking process. Another explanation is that milk could be related to stimulation of the esophageal reflex and stimulate the sucking process. It is also thought that the sucking behaviour is a positive feedback loop, in that when a calf sucks their mother it increases the calves motivation to continue sucking. This positive feedback is necessary to ensure that the calf concentrates on suckling when milk is available and thus completely drains the dam's udder. However, calves that are bucket-fed are not allowed to exhibit this sucking behaviour even though there is a strong motivation to do so. Thus the ingestion of milk motivates the calf to engage in cross-sucking and once they start the positive feedback motivates them to continue sucking.

Treatment for Cross-Sucking

There have been a number of treatments that have been tried to decrease the incidence of cross-sucking with mixed results. Some of the suggested remedies for cross sucking include:

  • Separation: This treatment uses the separation of calves to inhibit cross-sucking. It has been proven that tying calves up for 10 min. after feeding is very effective in stopping the incidence of cross-sucking (De Passille et al 1992). It has also been suggested that individually penning the animals for at least 4 weeks after birth is another way to inhibit cross-sucking. However, if the calves are penned too close together one calf could reach the mouth or ears of a neighbouring animal and engage in cross-sucking, thus this type of separation would be ineffective. Another problem with this remedy is that it inhibits the animal from expressing the behaviour, but does not inhibit the motivation to express the sucking behaviour.
  • Mechanical Devices: This is any type of muzzle which has been designed to interfere with sucking but not with milk ingestion (when bucket fed). Although this remedy is quite effective it has the same problem as separation in that the animal is still motivated to suck.
  • Dry Feeding: This is the practice of feeding concentrate or rough textured hay to the calves shortly after their ingestion of milk so as to distract them from cross-sucking. Although this remedy is not completely effective it is thought to have other advantages such as helping with rumen development (Morrill et al 1981).
  • Artificial Teat-Feeding: Feeding calves their milk via an artificial teat allows them to exhibit a natural sucking behaviour. An interesting point brought up by Hammell et al (1988) is that satiation (the feeling of fullness) with milk alone does not eliminate the sucking stimulus, thus even if the calves nutritional needs are met it still feels the need to suck. Artificial teat-feeding helps the calf feel satiated because the sucking stimulus has been shown to increase levels of cholecystokinin (CCK) (a mediator of natural satiety) and insulin over bucket fed animals, making teat fed animals feel more satiated. Lidors (1993) feels that there is a negative feedback of satiety on cross-sucking and thus the more satiated a calf feels the less likely it will engage in cross-sucking. Another benefit of artificial teat-feeding is that it takes longer for the calf to feed and thus the time spent feeding is closer to normal which will also decrease the likelihood of cross-sucking.

    My recommendation is that artificial teat-feeding is the best way of minimizing cross-sucking. calf
suckling artifical teat

    However, if the producer is unwilling to feed via an artificial teat then installing a dry rubber teat is the next best way to distract the calves from cross-sucking. The major problem associated with providing an artificial teat in this situation is that the calves will vigorously suck the dry teat and wreck it (especially as the calves grow older and suck or butt the dry teat more aggressively) which could get costly due to having to constantly replace the nipple.

    Conclusion

    The above treatments by themselves may not be 100% effective, however, if two or more were used in conjunction with each other their effectiveness would dramatically increase. Remedies which allow the calf to exhibit the natural sucking behaviour are going to be more beneficial to the welfare of the animal and could possibly increase rate of gain or performance.

    References

    Lidfors, L.M. (1993). Cross-sucking in group-housed dairy calves before and after weaning. Applied Animal Behaviour Sciences, (38) 15-24.

    Morrill, J.L., Dayton, A.D., (1981). Methods of feeding milk and access to fiber sources for young calves. Journal of Dairy Science (64) 146-148.

    De Passille, A.M.B., Metz, J.H.M., Mekking, P., Wiepkema, P.R., (1992). Does drinking milk stimulate sucking in young calves. Applied Animal Behaviour Science (34) 23-36.

    Hammell, K.L., Metz, J.H.M., Mekking, P., (1988). Sucking behaviour of dairy calves fed milk ad libitum by bucket of teat. Applied Animal Behaviour Science (20) 275-285.

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