Cattle farm husbandry – the bull

Cattle, farming, husbandry, the bull, age to buy, horns or polled, puberty age, libido & fertility, traits to look for when purchasing, performance records, management when with cows and aferwards, ringing a bull, safety in handling.


By Dr Clive Dalton

Can you do without a bull?


It’s a good idea to try avoid keeping a bull for these reasons:

• Bulls are dangerous and regularly injure and kill people. Include them on your OSH hazard list near the top.
• They are generally expensive if you buy a decent one.
• They eat more than a cow - sometimes nearer what two small-breed cows would eat.
• They break fences and gates and visit neighbours’ cows when not invited.
• They love digging holes to mark their territory - and as soon as you fill them in they dig them out again. Then other bulls come and enlarge the holes which fill with water.
• They love to fight with other bulls, especially strange bulls belonging to neighbours.
• They get very territorial and dangerous as they get older.
• They can be very musical and roar all night at other cattle in adjoining paddocks.
• You’ll need to change a bull before he comes round to mate his daughters.
• As bulls age they often get arthritis and feet problems, and these can be a major job to treat and need special facilities and vet bills.
• Bulls can spread venereal diseases through the herd.
• There is always some concern about a bull’s fertility and sex drive – both can vary over time.
  

What are the alternatives?

• Use Artificial Insemination (AI) or Artificial Breeding (AB).
• Borrow or lease a bull. Leasing a bull is now common with dairy farmers, and there are plenty of people who supply a wide range of dairy and beef bulls for lease. These bulls must have been tested for Tb and EBL, and now vets are recommending that they be BVD free as well.
• Do not take any animal on to your property without clear evidence of freedom from all of these diseases. Check with your veterinarian about these disease threats.
• Take your cows to the neighbour’s bull. You will have to pay a grazing and service fee. The cost could be about $12/week for grazing, and the price of the bull divided by the number of calves he produces.
  
• There are a few ways to work out these charges. But again, make sure the bull and the herd your cows are going to for mating are disease free - especially their Tb status.
• Share the bull, week-by-week-about with a neighbour. Remember that a cow cycles every 21 days so if you are second in the queue for the bull, your calving dates will be later by these intervals.
  

What age of bull to buy?

• Generally it’s best to buy a young bull, as there are generally fewer risks with health and physical problems like feet and being overweight.
• A yearling bull can be ideal, provided you put him with experienced older cows as he may have to learn a few tricks of the trade. It won’t take him long.
• It’s a good idea to put an older experienced bull with young heifers, provided he is not too heavy and may damage them when mating.
• It’s important to realise that the age of the bull will not affect the size of the calf at birth. It’s the bull’s genetics that dictate this, and the size and feeding of the cow during pregnancy.
• Using a yearling bull on heifers to avoid calving troubles may not work. He may have the genes for high growth rate, which he will pass on to his calves, starting at birth, regardless of his age when he is used.
• If you use a good bull as a yearling, he will retain a lot of his value as a two-year-old if you want to sell him the next season for breeding. An older bull after use is more likely to be valued at works price as a potter bull which will be good because he’ll be heavy.
  

Horned or polled bulls?

• Horns are pre-historic appendages not needed on modern cattle. They bruise meat, damage hides, and injure people. They are certainly weapons you don’t want to have on a bull.
• Give high priority to breeds that are polled, and if you need to use a horned breed, get your veterinarian to dehorn him properly as soon as he arrives on your property. This will be a messy operation that will cost you money.
• Cutting the tips off a bull’s horns is not proper dehorning and can make them more damaging.
• Don’t lease horned bulls as the risks are too great.
  

Puberty
Bulls reach puberty around 9-12 months old but young bull calves from 4 months old sucking their mothers can become sexually active so it pays to watch them. It’s only their lack of reach that prevents them doing the job!

Libido and fertility

• “Fertility” is the bull’s ability to produce viable sperm, and to measure it you need to check a sample of his semen.
  
• Only bulls at AI centres are trained to serve into an artificial vagina (AV) so on the farm a semen sample is obtained by electrical ejaculation.
  
• This is not always reliable as you only get a trickle out of the bull and not a good ejaculation as with an AV.
• You can also check fertility by seeing how many cows return to oestrus after the first 18-24 days of him joining the herd. But if he’s infertile you will have lost time on calving next year.
• “Libido” is the bull’s sex drive. He may have plenty of it but be infertile, so the two may not go together. His sex drive for females may take time to develop if he has been reared in a homosexual group of young bulls. He may need time to learn his trade.
• Some beef breeders now offer bulls after having a libido test done before sale. This “serving capacity” test indicates how many times the bull will mount and correctly serve a female held in a headbail in a certain time. It has to be done under veterinary supervision as the restrained females can get knocked about and injured.
• If your newly-purchased bull has libido or fertility problems, contact the vendor or your vet immediately, as you should be able to claim money back or get a replacement animal.
  
• Top breeders will always replace defective bulls, but you will have lost time finding out and next year’s calving will be delayed.
• Bulls will mate all year round and do not show a “rut” like sheep, goats and deer.
• Mounting and ejaculation are very quick by a bull where he grasps the cow with his front legs and his whole weight is propelled forward on the cow on his final thrust. This can be a tonne of beef in a large bull and can damage a heifer if she goes down risking breaking her legs and pelvis.
  

Physical traits should you look for in a bull

• Feet - the bull should stand evenly on all claws of all feet. There should be no misshapen claws or crossed toe nails.
• Walking - he is going to have to do a lot of this, as well as mounting on his hind legs. Make sure he can walk freely and his back legs don’t look too straight or stiff (called post legged). He should have flexible pasterns and hocks. Give him a “hurry-up” and see if he can move easily. The owner may not like this but it’s your money you are spending.
• Testicles - these should be large as sperm capacity is related to size. At some bull sales scrotum circumference is recorded in the catalogue. The testicles should be loose inside the scrotum if you’re brave enough to feel them. If in doubt get a vet to check them along with the health of the bull’s penis. Good vendors have all this done before sale time.
  

Where is the meat?

• You can spend a lot of time over the finer details of "conformation" but just make sure the meat is on the rear end (the expensive cuts) rather than the front end (the cheap cuts).
• And make sure that the bull looks like what a bull of that breed should look like, (in trade terms “true to type”).
  
• Use some experienced person who knows stock to help you assess this.
  

Breeders with performance records?
Buy from a breeder who has a sound breeding programme and is making genetic progress. The NZ Beef Council, PO Box 4025, Wellington, will give you advice on this.

What to do when you get a new bull home

• NEVER TRUST A BULL –and if in any doubt, always have someone and/or a good cattle dog with you when handling a bull.
  
• A hand-reared friendly pet bull is the most dangerous of all as one day he’ll want to play with you!
• Give a new bull a quiet journey home in his own pen in the truck.
• Unload him carefully to avoid injury.
• Put him in a well-fenced paddock within sight of other cattle or give him some steers for company and keep an eye them.
• Keep him away from other bulls - in both sight and sound if possible.
• Check that he has respect for electric fences and gates. If not, you’ll have to have a strategy to fix this problem quickly, or he’ll build on his experience and become an escapologist.
• Six metres is a bull’s “flight or fight” distance so keep out if it as much as you can.
  

How many cows per bull?

• A good rule is 3% + 1 bulls for cows, and 4% + 1 for heifers during the main mating season. Never have less than two bulls available.
• If you have not fertility-tested your bull, change him over with a different one every 7-10 days depending on how he looks. Veterinarians regularly find 10% of bulls are infertile which is far too high a figure.
• It takes 60 days for sperm to mature in the testicles so make sure all bulls are in top health long before mating.
• Fighting among bulls is common during mating, so watch for injuries to shoulders, legs, and penises. Change bulls more regularly if they are prone to fighting and you may have to find a combination of bulls that agree to get on together and share the work.
• For bulls to run with the cows after an AI programme is finished (called tailing up), then assume that about 60% of cows should be pregnant and then 3% +1 bulls should do the job. There should not be a lot of work left for them to do but keep a close eye on this just in case.
  

Management when the bull is with the cows.

• Let nature take its course but be vigilant and check the bull (or bulls) every day.
• Check that he is achieving a proper erection when mounting the cows and is serving into the cow's vagina correctly.
• Make sure that a bull actually has a good ejaculation with all four feet off the ground in the final thrust. If he just seems to “fiddle about” and doesn’t ejaculate with a cow on standing heat, then suspect a problem and have your veterinarian check him.
• A bull may serve a cow up to 3 times before she stops accepting him. Separating the bull from the cow is danger time for the handler, as the bull always wants one more service and will try to get back to the cow - perhaps with you in the way.
• Keep checking for injuries and exhaustion if he is losing interest and not working.
• He may be lying down a lot which should be viewed with suspicion. Give him a week off if you have another bull available.
• On a small block with few cows, boredom will be the bull’s main problem. Watch that he doesn’t start to pay too much interest in the neighbours’ cows or bulls – and start showing his dominance over you too.
  

Management after mating

• Work out when you want calving to finish and remove the bull 283 days before that date. There can be a 14 day spread either side of that pregnancy date.
• Take the bull out and put him in a separate paddock with some mates if you want to keep him. With a quiet bull he may be quite happy in a paddock on his own as long as he is within sight of other cattle.
• He may need to build up condition lost during mating, but make sure he doesn’t get too fat.
• If you are not worried about calving spread, then just leave him with the cows all the time. This is not a good idea.
• If you are not keeping him, book the truck to his next destination (sale or slaughter) the day he comes out from the cows unless he’s really skinny and you want to put some weight on him. It’s often wise to forget about adding value and bid him farewell!
  

A nose ring or not?

• If your bull does not have a ring in his nose, then forget about the idea.
  
• And if he does, then don’t ever think you can control him by hanging on to it, as bulls are far too strong. If you insist on a bull having a ring, then get your veterinarian to put it in using an anaesthetic for the nose and a shot to keep the rest of his bulk quiet. Never try to put one of those self-piercing rings in without a vet as you’ll get killed.

Farming bulls for beef

• This is a very specialist enterprise and is not for small farms or lifestyle blocks.
• Management needs to concentrate on keeping the bulls quiet and feeding them well to average 1kg/head/day over the 12 months they are on the farm, and then getting rid of them so you operate an annual programme.
• Any stress or disturbance in the system will be exploited by the bulls and they’ll waste time fighting, riding and injuring themselves – and not putting on weight.
• The love to dig holes to claim territory and strip and break young trees.
• The will wreck fences and gates and often dig holes below fences in confrontations with stock in the next paddock.
  
• Once an injured bull is taken out of a mob, unless he recovers within a few days, putting him back is a lost cause as he’ll be seen as a stranger and be ridden and injured again – and even killed.
• The best systems are either to set stock them with plenty or room to avoid conflict, or keep them intensively and move them on to new feed every one of two days.
• Get rid of them before they get territorial after 12 months old.
• Some bull beef farmers keep a Jack donkey with each mob to stop fighting. The Jack seems to act as part referee and part bouncer but donkey breeders hate this as the donkeys can get injured and they go lame with “founder” eating all the high-protein grass and bull farmers never trim their feet.
  

Disclaimer This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

Sheep Farm Husbandry - Reproduction and the ram

By Dr Clive Dalton

Ram correctly serving a ewe in full standing oestrus

It’s too easy to forget about the ram. They certainly get plenty of attention during their selection and purchase, and up to the day they are joined with the ewes, but when they’ve done their work, there’s a great temptation to put them in the back paddock and forget about them. In this modern age of “disposables’ the ram fits in well; we use them and then throw them away. They deserve better.

Basic ram facts

• Ram lambs reach puberty about 6 months of age, but beware of even younger ram lambs missed at docking that can easily be fertile by autumn. Their hidden identity seems to make them more virile!
• Rams are most active in the autumn but most would mate a ewe on heat at other times of year. Mating activity, as in ewes, is stimulated by declining daylight. Rams show a kind of “rut”, but nothing as obvious as seen in goats or deer.
• Rams rarely stop to eat hence lose a lot of weight during the joining period.
• Rams start to produce a strong aroma approaching mating and the bare skin around their eyes and on their underside around front legs and crutch turns pink. They are “in the pink”. For humans with sensitive noses the aroma is similar to a Billy goat but thankfully not as strong.
• This smell comes from the grease in the wool and contains a pheromone that stimulates the ewes to ovulate and show oestrus.
• Rams with high libido may not be fertile – it’s easy to assume they are if you see them enthusiastically courting ewes.
• Courting behaviour is made up of a lot of “sniff hunting” ewes. Rams approach a ewe often from side, pawing her side with head low, rattling his tongue and giving a low bleating.

Ram 'sniff hunting' ewes. He has found a ewe on heat.

• What most farmers do is to rely first on a veterinary check of the rams’ reproductive organs and then change them after each cycle to lessen the risk of any individual being infertile. The flock is mated alright, but you never know which rams were not fully functional and you may keep them – and their progeny which is always a concern incase the defect is inherited.
• There is a big decline in the number of sperm/ejaculate in the mating period reaching the lowest levels 8 days after mating. But after the first cycle of 17 days when things quieten down a bit, the semen quality builds up again. The drop of in sperm number doesn’t seem to affect ewes getting pregnant.
• It’s always wise to use an older experienced ram on young ewes, and a young ram on older experience ewes.
• As rams are reared in homosexual groups, they may take time to learn how to mate females correctly. Find time to watch new rams working to make sure they are serving correctly into the vagina and ejaculating properly. In a good ejaculation the ram will thrust forward with all four feet off the ground.

Vet checking of rams

• It’s very important to get your veterinarian to give all rams intended for use a physical examination well before joining with the ewes.
• Sperm development takes 8 weeks so all the sperm present when the rams are joined have developed prior to mating. So it’s important to get the vet checks done at least two months before joining.
• The newly purchased rams will, if anything, be overfat and lazy because they have been fed well for sale. They should have had a thorough vet check before sale.
• Newly purchased rams should have come with a veterinary certificate to show they have been tested within 60 days of the sale and are free from Ovine Brucellosis.
• If they are going out on to hill country they’ll need exercise training. Put them in a steep paddock near the dog kennels where they will get regular disturbance or make them move every time you pass them on foot or in a vehicle.
• Some farmers put new rams in their driveway so every time a vehicle goes along (hopefully slowly) the rams are chased the full length and back again. Make sure the rams respect the cattle stop at the entrance or they’ll be gone!
• For older rams resident on the property, they may need special checking as they are often neglected after mating and may have a range of health problems.
• It is especially important to check any rams that will be used in single-sire mating mobs.
• In a standing position check the ram’s testicles through his back legs.
• The testicles should be large and hang close to the ground. They should not be tucked up near his body.
• Big testicles denote large sperm producing capacity and a scrotum circumference of 30cm or greater is considered to be adequate.
• The scrotum should feel smooth and silky and not look like crusty corduroy!
• The testicles should feel loose in the scrotum and not have any adhesions to the scrotum wall.
• Feel for a small lump at the very base of the testicle – that’s quite normal and it’s the epididymis or coiled tube for holding the sperm before they go up the vas deferens. The vas deferens is the tube the vet cuts or ligatures above the testicles when the ram is vasectomised. The epididymis should feel rubbery and not rock hard.
• Never use a ram where the testicles feel small (and the epididymis feels a similar size) and is hard. This is bad news for the ram as you would be most unwise to give him a job!
• Now turn the ram over on to his rump and check for old shearing cuts and wounds that may have been flyblown and not healed.
• Check the prepuce or sheath the penis is in. It should not be swollen or exude pus from the end as this is probably “pizzle rot”.
• Any urine stain or dirty wool around the end of the prepuce should be viewed with suspicion.
• The “button” at the opening of the prepuce has some long hairs on it – don’t shear these off as they help urine to drain away.
• With a little pressure at the rear of the prepuce, you should be able to protrude part of the ram’s penis. It has a slight bend but should not be any abnormal shape.
• Don’t panic if you see what appears to be a worm coming out the point (the glans) on the end of the penis. This is normal and for some reason the ram is unique in having such a structure which is believed to help sperm get through the ewe’s cervix.
• Check with your vet about the need for vaccinations against Brucellosis. All newly-purchased rams should have been treated.

Ram showing the 'flehmen' response after sniffing a ewe's urine

Libido and fertility

• A fit ram is capable of completing at least 10 services in 8 hours and some can do 20 or more. The concern is usually about their fertility.
• “Fertility” is the ram’s ability to produce viable sperm, and to measure it you need to check a sample of his semen. Only rams at AI centres are trained to serve into an artificial vagina (AV) so on the farm, a semen sample is obtained by electrical ejaculation. This is not always reliable as you only get a trickle out of the ram and not a good ejaculation as with an AV.
• You can also check fertility by seeing how many ewes return to oestrus after the first 17 days of him joining the flock. But if he’s infertile, you will have lost time on lambing next year.
• “Libido” is the ram’s sex drive. He may have plenty of it but be infertile, so the two may not go together.
• Some ram breeders are doing “serving capacity tests” before they decide on how many ewes to give them. The test measures how many successful services the ram achieves in a given time – e.g. a ram confined in a pen with four oestrus ewes for 20 minutes should have at least two or more ejaculations.
• This test has animal welfare implications so check with a veterinarian on the approved method. Remember also that the pen confinement may affect the ram’s behaviour.
• If your newly-purchased ram has libido or fertility problems, contact the vendor or your vet, as you should be able to claim money back or get a replacement animal. Top breeders will always replace defective rams, but you will have lost time finding out and next year’s lambing will be delayed.

Mating ratios – how many ewes per ram?

• Mating ratios have traditionally been 1 ram to 40-50 ewes, but this has probably grown with the belief that you had better have more rams than needed incase one is infertile. It’s still the standard advice today, and ram sellers don’t want to change it.
• This is terribly wasteful of ram power as many trials have shown that a good fit ram is well able to mate 100 ewes, and some have mated up to 400 ewes where maximum coverage was needed without the need for Artificial Insemination (AI).
• On large hill country blocks you have to watch out for rams that go away with a harem of ewes. The solution is to muster the sheep together at least once a day to make sure the ram or rams have contact with all the flock ewes.
• So if you had chosen to put one ram to 100 or more ewes, it’s important to have good flat or rolling country so he could easily keep in contact with the flock to be mated and not have to search gullies or scrub for them.
• Much depends on the health and fitness of the ram before the start of mating, and old shepherding lore says that rams must be “fit and not fat”.
• Most fit rams are capable of at least 10 services in 8 hours and many are capable of 20 services.
• A high-libido ram in the first days of joining always wants to give the ewe one more service, but generally after a couple of mounts and good ejaculations the ewe is less receptive for more, so the ram moves on to look for more business.
• In well synchronised flocks you often see ewes queuing up for service in the first week of joining. In this situation a ewe may only get one service as her partner has been called away!
• Ram lambs that are large enough (30-40kg) are usually given 30 ewes but if you are pushed, a lamb could mate 50 ewes over a couple of cycles.
• Research has shown that differences in ram ratios do not affect the number of twins born.

How many rams in the mating mob

• Having a surplus of rams in the flock may be a good insurance against infertility but they will spend more time fighting and establishing dominance and may miss ewes on heat. Fighting also leads to injuries which rarely recover before the end of mating, so an expensive ram can often be a write off.
• In large mobs where many rams are used, the dominant rams do most of the mating, chasing the less-dominant away. Practice makes perfect, so these dominant rams, getting more practice, do the job quicker and so get more work.
• However, many ewes end up being mated by more than one ram, and is often seen when mixed breeds of rams are used to find twins by different sire breeds. It has also been identified by DNA profiling.
• This can have some benefits to overall flock fertility, especially if the semen quality of a dominant ram is declining due to over work. Studies showed that returns to service were 7-10% higher in single-sire mating mobs than where many rams were present to do the mating.
• The subordinate ram may get a service when the dominant one has moved away to find more fresh ewes, or with ewes that have come to him and are waiting for mating.
• Behaviour studies have shown that rams can be racists – in mixed-breed groups they often show a preference to mate ewes of their own breed. This was found in Merinos and black-faced breeds.

Research
Extensive research on mating ratios was done at the Invermay Research Centre by Dr Jock Allison in the 1970s.  This is reported in:
 Allison, A.J. (1975). Optimum  ram/ewe mating ratios. Proceedings of the Ruakura Farmers' Conference, 8-13.

The “ram effect”

• Old shepherds always knew that the sight and smell of a ram stimulated ewes to cycle. Not surprisingly, modern researches have proved they were right and called it “the ram effect”.
• The main reason to exploit it is to stimulate ewes to come on heat earlier than they may have done to try to get some early lambs, and to synchronise the flock to reduce the spread of lambing.
• Prior to the breeding season, most ewes will ovulate but not show heat signs. This is a “silent heat” so she is never mated.
• Joining rams prior to the start of these silent heats will stimulate ewes to ovulate within 3-6 days and show a proper oestrus 17 days later at which they can be mated.
• So timing is critical. If the ram is joined too early there will be no “ram effect”, and if joined too late the only ewes affected will be those that have not yet had a silent heat.
• To really exploit it, ewes are first isolated from sight, sound and smell of all rams for at least 2-3 weeks before joining.
• Then both sexes are put in adjoining paddocks to view and smell each other through the fence. Then the ewes can smell the male “pheromones” which are in the wool grease of the ram when he starts to stink like a Billy goat. The more powerful the smell, the better the results should be.
• After about 4 days the gate is opened between them for mating to start.
• This practice is sometimes done using teaser (vasectomised) rams that are actually run with the ewes for even closer contact and actual serving.
• Teasers seem to lose their libido over time and young entire rams can have more oestrous-stimulating power when kept next to ewes through the fence.
• The other point is that it’s not always predictable what will happen as there are so many variables involved. Ewes must be in top body condition and so must the rams to get maximum benefit from the ram effect.

Shearing and dipping rams before joining with ewes

• Newly purchased two-tooth rams will have quite a bit of wool on them for the buyer to assess, so they will need to be shorn before joining.
• If you buy rams before Christmas (which is a good NZ practice), then shear them on arrival at your farm.
• This will keep the ram cool during mating and the new wool will be long enough to keep a mating harness in place.
• Shearing very close to joining is generally not recommended incase the shock affects fertility. This will not be very likely if the ram is in good condition.
• Dipping rams before joining is definitely not recommended as it may have bad effect on semen quality. This is not a well-researched area, but it would be wise to be cautious and not dip for six weeks before mating.

Using ram mating harnesses
A mating harness can be used for three reasons:

• To find out if a ram is working and which ewes he has served.
• To sort the mated ewes into lambing mobs.
• To identify barren ewes for early culling.

Old-time shepherds used to take a pot of raddle and a stick and put liberal amounts on the ram’s chest so when he mounted and served a ewe, a mark was left on her rump. This was a messy business that had to be done two or three times a week.

You had to catch the ram and wrestle him over to do the job properly, ending up covered in raddle. It was not surprising that after this indignity and the sight of the pot and stick, he became forever harder to catch!

Thankfully this all became unnecessary when the ram harness was invented. This fits around the ram’s girth behind the shoulders and holds a coloured crayon on his brisket to mark the ewe during each mount. He may leave a small mark after a false mount but usually after a good forward thrust and ejaculation, he’ll leave a good a strong crayon mark. Here are a few points about getting good results from the harness:

• Make sure the harness is properly fitted on the ram and that neither it nor the crayon holder chafe his skin, especially under the front legs.
• It has to be fitted tight to keep the crayon on his brisket.
• Check it regularly.
• Make sure you use crayons of the correct consistency. Hard crayons are for warmer conditions and soft ones for cold. Try some intermediate crayons if you are not sure, but check if the marks are clear.
• Care of harnesses is important both during and after mating. They may stretch (especially leather ones) and need more holes punching in the straps.
• Leather harnesses may need oiling which makes them very attractive to rats so good storage after mating is important.
• Store synthetic webbing harnesses out of direct sunlight.
• Using colours to separate lambing mobs

You can use two basic systems to do this:

Use one colour and draft off marked ewes.

• This eliminates the need to keep changing crayons but it means more handling of ewes in the sheep yards.
• At given intervals (e.g. 8 days which is half the cycle) draft off the marked ewes.
• Run these ewes with a ram fitted with a different coloured crayon.
• About 10-13% may return to service and those that don’t can be spot marked with a raddle on the head or back with an appropriate colour to denote the first lambing mob.

Change crayon colours

• Catch the rams after each 8-day period and change their crayons.
• A good colour sequence is:
• Start– no colour or yellow
• After first cycle – red or orange
• After second cycle - purple or green
• Third & fourth cycle - blue

Not using crayons will reduce contamination of the wool as hopefully most ewes will be pregnant soon after the ram is joined.

You can decide how many cycles you are going to accept before the ewe is considered as a cull. If not pregnant by two cycles, then she should be a candidate for culling unless there are extenuating circumstances e.g. an infertile ram.

All ewes with blue rumps are clear candidates for culling. The odd one may be pregnant but this is not worth worrying about as she will lamb so late.

What to do with the information?
If the harnesses have done the job they were designed for, then you will know which weeks the ewes will lamb in, which is very important information to plan feeding. The information is not perfect of course, so you will always be suspicious of ewes that are supposed to be in a later lambing round that are bagging up rapidly.

How long to keep a ram?

• The answer to this question is straightforward – change rams before they come round to mating their own daughters.
• So if you buy a two-tooth ram to mate ewes in autumn 2005, his daughters will be hoggets in autumn 2007 (if you wanted to mate them) and two-tooths in autumn 2008.
• If you have high Index rams that you will clearly want to use over many flock ewes in future, then you’ll have to use single-sire mating to identify his progeny or use DNA profiling.

Rams for small flocks

• Here the main problem is boredom for the ram. He mates all the ewes in the first cycle and then spends the next month at least sniff hunting them every time they move in the vain hope of some work.
• It’s no wonder he breaks out into the neighbours or out the main gate and goes to town!
• On too many small farms the quality of the rams used is dismal as they are viewed simply as something to get the ewes pregnant, and they have been bought for a give-away price at the late ram sales.
• Lambs these days are worth big money and the best way to work out what to pay for a ram is to divide his cost by the number of lambs he will sire at say $70 each. So a rubbish ram at $30 is not a good buy.
• Small farmers should consider cooperating in buying a good ram between them with some good performance records, and if convenient putting their ewes together for joining or giving the ram one cycle at each property. Late lambing ewes are not such a problem on small farms where they get more attention.
• It’s not a good idea to keep a pet lamb as the flock ram as there have been some nasty accidents by them knocking over owners and their children at mating time.

Artificial insemination (AI)

• In New Zealand, widespread commercial AI in sheep has not developed yet. It’s only been used by breeders with high-value rams and for “sire referencing. Here a group of breeders use the same ram at the same time as a “benchmark” sire, against which their own rams can be compared. This allows them to rank rams over different properties in a sire comparison or progeny test.
• Commercial AI services only develop when the sires available are of such high in genetic merit that masses of farmers want them all at the same time. They are then prepared to pay the charges and also accept all the extra on-farm work which may include some technical training in semen handling and insemination technique which is more difficult that with cows.

Basic facts on sheep AI

• The best quality semen for AI comes from rams that ejaculate into an artificial vagina (AV) and not from electroejaculation, so rams have to be trained to serve into an AV and this can require special skills.
• This is why many farmers send their rams to commercial AI stations for semen collection and also for storage. From here they order what semen they want each day.
• Normally 2-3 ejaculates are collected from a ram in a day.
• This would give enough sperm in 0.1ml of semen to mate 50 ewes.
• Because of all the extra work involved in AI, it’s a good idea to synchronise groups of ewes in the flock to come on heat together. This is done by treating them with intravaginal devices (IVDs) containing progestagen. The IVDs are left in for 12 days and after removal will come on heat 48 hours later.
• All the ewes are inseminated - sometimes called “blanket insemination” or “fixed-time” insemination.
• The other method which gives better results is called “on heat” insemination which means that a teaser ram is used to identify ewes on heat and they are brought in twice a day for insemination.
• Ewes ovulate after the end of standing oestrus, but the problem is you don’t know when they start, and the exercise has to fit in with working hours.
• When using a harnessed teaser ram to identify any on heat, bring in any ewes that were marked overnight and inseminate them that morning.
• Then in late afternoon bring in any new ewes found on heat and inseminate them. It would be a good idea to give these late ones another insemination the next morning if the teaser was still interested in them. A further insemination 10-12 hours after her first insemination can increase fertility by 6-10%.
• There are two methods of insemination. Ewes are inseminated either into the cervix (cervical insemination) or into the uterus (intra-uterine insemination). Only a veterinarian can carry out intra-uterine AI.
• With cervical insemination an experienced operator can do 50-60 ewes/hour with fresh semen, and with intra-uterine, 25-35ewes/hour is a good work rate with frozen semen.
• “Conception rate” (CR) after AI is normally lower than by natural service.
• Good operators will guarantee 60% CR for intra-uterine and 50% for cervical AI.
• Fresh semen must be used within 24 hours of collection for cervical insemination and frozen semen is only suitable for intra-uterine insemination.
• Keeping stress to a minimum is important in an AI programme. By the time a ewe on heat has been mustered, yarded, drafted, restrained for insemination and then had a speculum inserted into her vagina to light up her cervix for insemination – she may be more than a bit stressed which may affect conception rate.
• Clearly it would be most unwise to consider an AI programme in sheep without consulting your veterinarian and a professional AI service provider.

Animal behaviour and welfare: Cattle Part 3

CATTLE BEHAVIOUR BASICS: PART 3

Reproduction: Cows: Bulls: Birth: Cow-calf relations

By Dr Clive Dalton


Cows

• 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).

Signs of heat in the cow

• 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.

SAG. Which cow is on heat, which ones coming on, and which ones going off?

• 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.

Heat detection methods

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.

• 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.
  

Birth

• 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.

First stage - cow lying pressing and water bag appears
(Photo Karen Managh)

• 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.
  

Social order in cows & calves

• 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

• 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.

Bull libido

• 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

Yearling Friesian bulls reared 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.