Management of beef heifers during and after calving
Management during calving
The main aim of management during calving is to minimise deaths of calves and heifers that may result from a difficult calving. Heifers must be observed frequently, but disturbed as little as possible.
Heifers should be observed at least twice daily, more often if practical. Assistance can then be given early if needed. To be born alive, the calf must be delivered within approximately four hours after the appearance of the water bag. Early assistance can avoid deaths, calving paralysis and uterine prolapse in heifers.
Heifers should be kept close to cattle yards during calving, so that early assistance may be given if needed. The labour required for supervision can be kept to a minimum if the heifers are joined to calve over a short period, (6-8 weeks). Keeping the heifers in a small paddock close to the house during calving can also reduce the time required for frequent observation.
Calving difficulty can be induced by disturbance. Hence, frequent checking must disturb the heifers as little as possible. Reasonably quiet cattle may be inspected by slowly riding through the mob on a horse. Binoculars are an option for excitable cattle.
Deciding when to assist
The calf should normally be born within two hours of the appearance of the water bag. If the calf is not born within three hours of the appearance of the water bag, the heifer should be examined. If there is any doubt about the time of the appearance of the water bag, an examination should be carried out immediately.
The decision to give assistance should be based firstly on the position of the calf. If a hind leg is visible or if only one foreleg is presented, or if there is any other evidence of mal-presentation of the calf, assistance should be given immediately. The calf's chance of survival is greater if assistance is given early.
If the position of the calf appears normal, with the head resting on the front legs, then the condition of the heifer should be considered.
A heifer that has ceased straining and appears weak or exhausted should be assisted immediately. If the heifer is straining vigorously, and the birth appears to be progressing normally, the heifer should be left alone for approximately one hour. If there has been no real progress after the hour has elapsed, assistance may be required.
When to call the vet
When a heifer is found to have difficulty calving, and the examination has confirmed that assistance is required due to mal-presentation of the calf or weak condition of the heifer, veterinary assistance should be sought if the producer feels that a successful delivery would be more likely with professional help. In particular, a veterinary surgeon may be required to prescribe and administer any drugs required to assist with calf and heifer survival during and after calving.
After giving assistance
After a difficult birth, young cows in particular often desert their calves. It is wise to keep the cow and calf confined in a small area after assistance has been given. They can then be watched and should not be allowed back with the main herd until the cow has accepted the calf and will allow it to suck. Sometimes it may be necessary to hold the cow in a crush or race and force her to allow the calf to drink for the first few days.
Management after calving
Once they have calved successfully young cows are required to produce a good supply of milk and become pregnant again soon. To achieve this they must be well fed from calving until the end of mating.
The main factor determining how well calves grow is the amount of milk their mothers produce. This in turn depends on such things as the age and breed of the cow, but it is also influenced by feeding management.
Young cows produce less milk than mature cows. Consequently the growth rate of calves from two year-old or three-year-old cows is normally 10 - 15% less than that of calves from cows aged five or six.
Nevertheless. young cows can produce good calves if they are well fed after calving. Feed intake before calving has a relatively small influence on milk yield, but after calving the effect is enormous. Once they start to produce milk, cows of any age need at least twice as much food energy as they did before calving. If they don't get it they will lose weight and their milk production will be depressed.
After they calve, cows have only about 80 days in which to become pregnant if they are to calve again within 12 months. Whether they achieve this level of fertility depends on how soon after calving they come on heat again. This is largely determined by the breed of cow, the amount of milk produced, age, and feeding management before and after calving.
Milk production places cows of any age under much greater stress than pregnancy or any other body function. High milk-producing breeds and strains of cattle take longer to start cycling again after calving than lower milk producers.
Mature cows usually take about 60 days to come on heat again after calving; young cows may take 90 days or more. The reason is that young cows, particularly those calving at two years of age, are in a very delicate nutritional situation after calving. They require nutrients not only for milk production, but also for their own body growth and development. In contrast to this, the mature cow can, to some extent at least, "milk off her own back ".
Nutritional management both before and after calving has a great impact on cow fertility. Cows that are not well fed during pregnancy take longer to start cycling again after calving than cows that are well fed. Ideally cows should calve in medium body condition, preferably in condition score 2.5-3.0.
Cows must be well fed after calving. Although maximum fertility requires cows to be gaining weight from calving to the end of mating, it is likely that cows calving in autumn will lose weight from calving to joining, despite being fed. However, adequate fertility will be obtained if cows are calved in condition score 3, to join at condition score 2.5. It is therefore important to ensure that cows calve in good enough condition to allow for weight loss and yet still ensure adequate condition for joining.
Feeding young cows after calving
For good fertility and milk production, first calvers in particular must be well fed after calving.
Simply providing an abundance of good quality pasture may be adequate in some years. Some producers draft off freshly calved young cows each week, and drift them into a better paddock. In an autumn-calving herd, for example, this could be an "autumn-saved" paddock.
In most districts of Victoria, however, young cows calving in autumn usually require a high quality supplement after calving. Early or mid-season cut clover hay, early cut oaten hay and lucerne hay are suitable, but hay of lower quality is of little use. If good quality hay is not available, cereal grains may have to be fed.
Feeding should begin immediately after calving because cattle may take a while to adjust to the ration .
Young cows calving in autumn are particularly vulnerable to severe worm infestations. The stress of calving is believed to precipitate the release of large numbers of "inhibited" worm larvae from the walls of the gut. Appropriate steps should be taken to avoid this problem.
Geoff Kroker, Bendigo and Lisa Clarke, Hamilton