Weaning represents the single greatest source of stress that can be imposed on a calf and, to a certain extent, the cow too.
Research has shown that more calves are treated for disease and health problems immediately post weaning than at any other time in their lives. The abrupt separation of cow and calf causes dramatic visible changes in their behaviour. Both cows and calves eat and rest less following separation and they both walk and pace more in the days immediately after weaning. Weaning also produces some very audible signs of distress, like constant calling, which can last for several days.
Dr. Joe Stookey of the Western College of Veterinary Medicine at the University of Saskatchewan has done a lot of research on how to minimize the weaning stress in beef cattle.
It is already well known preconditioning calves, by weaning them at the farm a few days before transporting to the feedlot, offers better results in terms of health and performance than abrupt weaning and immediate transportation, says Stookey, who spoke at the recent Manitoba Grazing School in Brandon. But, he adds, it’s not common practice because producers often do not see an economic benefit in doing so, any more than they see a benefit in vaccinating calves before shipping. USDA figures show that 64 per cent of cow-calf operations are not vaccinating cows before they are being sold on, which means feedlots are treating between 10 to 25 per cent of their cattle for bovine respiratory diseases.
Stookey says many health problems could be alleviated with more gradual weaning to reduce stress and help prevent illness, although he admits some recompense to the cow-calf producer for these extra steps is essential for it to become common practice.
There are a number of stress factors associated with abrupt weaning. On most farms calves are typically weaned at a much younger age than they would wean naturally. Studies have shown this is even more of an issue for bull calves, that would naturally wean at around 11 months, than for heifers who would naturally wean at eight months.
Weanlings are also suddenly confronted with a completely new and unfamiliar social environment. Once separated from its mother, a calf has no pattern of behaviour to learn from and will feel lost and helpless. Add to these factors the shock of transportation to a new location and the introduction of a completely different diet, and it’s little wonder that calves easily become sick.
To minimize weaning stress, studies in the 1980s and ’90s looked at fence-line (or contact) weaning, where calves were physically separated by a fence at weaning time, but still had their mothers in sight. The results were encouraging and seemed to reduce many of the visible signs of stress in the calves. They walked less, lay down more and grazed more readily than calves that were abruptly weaned.
The fence-line weaning experiences, however, seemed to raise an interesting question, posed by Derek Haley of the Ontario Veterinary College in his work on weaning stress. “Is weaning stress more to do with calves missing the milk or their mother?” he asked.
To answer this question further, on-farm studies in 2007 compared two groups of cow-calf pairs; one group was abruptly weaned and the other group was weaned using a two-stage process. In two-stage weaning a calf is denied its mother’s milk through the use of a simple anti-sucking device, developed in Argentina, which fits into the calf’s nostrils. After three to four days of not nursing the cow, the calf is separated from its mother.
The reduction in visible signs of stress was dramatic. The amount of calling by the two-stage weaned calves over the four days after weaning was a fraction of the abruptly weaned calves. The two-stage calves were considerably calmer, walked less and rested and grazed more readily. In the first two days after weaning the abruptly weaned calves walked on average around 12 to 13 miles a day. The two-stage calves walked around six miles on the first day and less than four miles on the second.
The overall health and performance of the two-stage calves was also dramatically different to the abruptly weaned animals. Weight gain of the two-stage weanlings was around 10 to 11 pounds in the first seven days after weaning, whereas the abruptly weaned group experienced a reduction in gain of almost 35 pounds on average in the first seven days post-weaning.
Although two-stage weaning seems to be effective in reducing stress and improving performance, the downside in the minds of many producers is the additional handling it requires, particularly when dealing with a large herd. But one producer involved in the study came up with an easy and cost effective way to sort the calves and separate them from the larger animals. Simply by removing the lower bars of one of his fences the calves were able to slip underneath into a separate pen, whilst the larger cows passed peacefully along beside them and were channelled into an adjacent corral.
“Even if we admit that the extra handling (with two-stage weaning) may be stressful (for producers) there is no way that it trumps the stress of five days of calling and bawling,” says Stookey. “If we had all started out with two-step weaning we wouldn’t stand a chance of selling producers on abrupt weaning now.”