Reproduction: Cows: Bulls: Birth: Cow-calf relations
By Dr Clive Dalton
- Cows will breed all year round in New Zealand latitudes and are not as affected by the day/night pattern (photoperiodicity) as sheep, goats and deer. But cows’ breeding activity may be reduced in the darker days of mid winter.
- Cows start to cycle usually about 6 weeks after calving. They can show heat 3 weeks after calving but rarely conceive to this mating.
- They may also show a “silent heat” with ovulation but no outward heat signs. More problems are seen in Holstein Friesians than Jerseys.
- A cow ovulates a few hours after the end of standing heat, which has important implications for artificial insemination to ensure an effective pregnancy.
- Puberty is about 6-9months of age but some heifer calves can show heat before that. This can be a hazard, as they can get pregnant as early as 4 months old and have to be aborted. It is not a good idea to let a yearling have a calf.
- Cattle cycle every 21 days (range 18-24 days) if not mated, and are on heat for about 8 hours (range 2 -12 hours).
- Vocalise a lot.
- Vaginal discharge - clear viscous fluid.
- Walk around a lot to find other cows.
- Cows form Sexually Active Groups (SAGs) of 3-5 cows.
- Cows on heat mount other cows.
- They stand to be mounted.
- They "hold' their milk” and don't have a full "let down".
- The cow is the only animal that shows this clearly defined persisting mounting behaviour, which is thought to have evolved to give visual signals to the bull.
- But note that a cow that will stand for another cow will not immediately stand for the bull. This has a “teasing” effect on the bull and while challenging his libido concentrates his semen as excess accessory gland fluid dribbles off.
Painted tail that has been scuffed off. Tail dock is illegally too short -
it must cover the vulva if removed. Tail docking is in decline now.
it must cover the vulva if removed. Tail docking is in decline now.
- The most common (and cost effective) method of heat detection used in NZ dairy herds is tail paint. The top of the cow's tail is painted with a thick paint, and when dry it is scuffed off indicating that another cow has mounted her. The traffic light colour sequence is best to use with tail paint.
- Other methods are to use a range of adhesive devices that trigger colours or show scratch marks when rubbed by a mounting cow.
- A "chin-ball harness" was developed to fit on the bull’s head and where a roller ball in a tank of paint left a mark on the cows back when the bull stood with his chin on the cow to test her stage of oestrus, when he mounted, and when he dropped back from mounting.
- A cow may spend couple of hours seeking out a birth site, and going through the first stages when the calf moves into the birth canal and the water bag appears.
- The next "delivery" stage where her waters burst and the calf appears should take about 15 minutes. If it's longer, then investigate what is going on or get help. The calf should be born in a diving position - front legs and head first. If not, you'll need to sort out the problem and may need professional help.
- The final stage is passing of the afterbirth, which the cow may eat for hormonal benefit and removal from predators in wild.
Final stage - calf safely delivered, and cow stands up to lick calf.
Rapid bonding takes place now. Afterbirth not cleared yet.
(Photo Karen Managh)
- Disturbance will upset and delay this pattern. It can have bad effects on the calf as it and the birth canal dries out and makes the process difficult.
- The calf should be on its feet in 15-30 minutes and should start teat-seeking. It's vitally important that the calf gets colostrum and it needs at least 2 litres before 6 hours old.
- The calf nuzzles the side of cow feeling for warm bare skin with teats. It can be very frustrating for calf, especially if their mother is a heifer as she may panic and turn to look at calf instead of standing still and encouraging suckling.
- Inexperienced dams may even attack the calf and not stand still and nuzzle calf's tail area to encourage it to suck.
- Bonding is very quick in cattle and takes only a few minutes. It is based first on smell and then on sight.
- This can lead to problems of recording accurate parentage in large herds where groups of cows are synchronised to calve together. Staff have to make dam-calf Identification decisions that can be 13% wrong. Fortunately parentage can now be confirmed by DNA tests.
- Most cows will not accept another calf after she has smelled and seen it unless you play other tricks on her (see later). But some cows will accept any alien calves.
- The calf will follow the cow or any moving object a few hours after birth.
- Calves often fall into drains during this early mothering period as they stagger about and can also fall on to the power fence and the constant shock on their wet body can kill them.
Cow calf relationship
Dexter cow and week-old calf. (Photo Karen Managh)
- When to remove a calf from her dairy cow mother is often debated as an animal welfare issue. The question is to find which system causes least stress on cow and calf.
- The general practice is to remove the calf as soon as it has had sufficient colostrum, which may be a few hours after birth. It is argued that this is less stressful than removal at four days when milk can go to the factory. The cow's colostrum production is reduced to acceptable levels after 4 days.
- In the wild, cattle are "lying out" species that hide their calves and suckle them at intervals during the day.
- The cow and calf spend the night together, have an early morning suckle then the calf lies down while the cow goes off grazing.
- An individual cow may graze close by her own calf and act as guardian of the crèche. If a calf bellows then its mother will return.
- Around mid morning, one or two calves will call out and most cows will then return to suckle their calves.
- The same pattern occurs in the afternoon. Then in the evening cows return to suckle and spend the night with their calves.
- After 2-3 weeks, cows are more closely associated with their calves that will then follow their dams to graze and rest near them.
- Cattle show a very clearly defined social order called a "bunt order" as they use their heads to sort it out.
- If cattle are horned, then they have a big advantage over polled cows. This may cause problems in mixed groups in yards and at slaughter plants.
- Horns bruise meat, damage hides and injure people and should be removed at birth with the hot cauterising iron and local anaesthetic, or genetically by using polled bulls.
- Social order can be a very important issue in milking herds affecting cow flow.
- It will be an issue with milking robot as dominant cows can block the flow through the unit.
- Social order is also important with communally fed calves. There is a need to regularly draft calves to keep them of similar size and hence reduce bullying.
- The social order developed in calves can last till they enter the herd.
- Social facilitation is important when ad lib feeding as one calf can trigger feeding.
- Group-fed calves are better socialised than those reared in isolation.
- Calves can discriminate between objects, black versus white and large versus small.
- Bulls will mate all year round and do not show a "rut" like sheep, goats and deer.
- Mounting and ejaculation are very quick in the bull. He grasps cow with his front legs and his whole weight is propelled forward on the cow at ejaculation.
- This has safety implications for heifers mated by large stud bulls that can damage them. Heifers are best mated by smaller bulls.
- A bull may serve a cow up to 3 times before she stops accepting him. In wild herds, the bull hangs around a cow for a day or both before and after mating.
- On the farm he is generally allowed two services and is then separated. This is danger time, as the bull always wants one more mount, and tries to get back to the cow. The human in the way is at high risk of being pushed or charged.
- Running one bull with 30-50 cows (dairy or beef) is normal practice, and the bull is changed regularly incase he is infertile.
- Fighting among bulls is common during mating and injuries are common, e.g. to shoulder, legs, and penis.
- In the wild Chillingham herd in UK, the king bull does all the mating until he is challenged by a young bull and they usually fight to the death for leadership.
- Bulls are regularly reared in homosexual groups from 4-18months old so mounting and fighting behaviour is common, often leading to injury. This is especially the case with beef bulls.
- Bulls may have to learn how to mate a cow, and this may take a few days to learn (and waste time) at the start of mating.
- Libido testing can be done using the "Blockey test" where a cow is restrained in head bail and the number of mounts made by each bull is recorded.
- This must be done under veterinary supervision to avoid injury to the cow, which must be changed regularly.
Farming bulls for beef
- Farming bulls for beef is a major enterprise in New Zealand and provides lean export beef (grinding beef) for the USA hamburger trade.
- Farmers run mainly Holstein Friesians, which are obtained as surplus bull calves from the dairy industry. Bulls grow well and should average 1kg liveweight/day over their lives.
- This is now a specialist enterprise where knowledge of animal behaviour pays dividends.
- After about 12 months, bulls become territorial and fighting often increases. They dig holes to mark territory and wreck fences and gates during their activity periods.
- Regular riding goes on and if one bull accepts this, he will be ridden regularly by others and can be injured. Bulls clearly prefer to ride rather than be ridden and will move away quickly from their assailants if they are strong to fight and then escape.
- Injured or sick bulls will be ridden to death if left in the mob and have to be taken out. Rarely can you put them back, even after a few days as they are seen as strangers again. If returned to the mob then become a good target to ride again and upset the whole mob.
- Mobs of beef bulls are less of a threat to neighbours' cows than is often imagined, as they seem to prefer their homosexual mates until they get a taste for female sex.
- Successful bull farmers use a few tricks to keep them quiet.
- Always keep them grazing. When they are idle or bored they play up.
- Run them at low stocking rates to give plenty of personal and grazing space.
- Try not to disturb them as they are very alert to changes.
- Have at least one empty paddock between mobs of bulls.
- Use shelterbelts so one mob cannot see the others grazing.
- Run a donkey Jack with the mob or a horned Billy goat to discourage fighting.
- Move them from a bike or horse with a good cattle dog and not on foot. Have help within reach.
- Always be alert to the sound of their roaring. They use a high pitched confrontation roar when they see competitors or may have got out.
- Don't graze bulls in paddocks near neighbours' cows unless the fence is very strong and electrified.