November 23, 2008

Animal behaviour and welfare: Deer Part 3


Reproduction: Birth behaviour: Handling: Capture

By Dr Clive Dalton

The female

Red deer hind

  • Females come into oestrus in the autumn with declining daylight and the "rut" of the male stimulates this further.
  • Farmed red deer females reach puberty around 16 months old when they weigh about 65kg. Body weight is important and hinds below 52-55kg generally do not conceive. Few problems are seen in the wild where stocking rates are lower and animals may be better fed and less stressed.
  • In the wild, females are attracted to the stag's rutting areas by his roaring. They may drift from one of these stands to another before they settle.
  • Red hinds come into heat every 18 days (26days for fallow) and will continue for about 8 cycles if she does not become pregnant.
  • Oestrus in Red deer hinds lasts about 24 hours during which she will be served by the dominant stag or other lower-order males.
  • The hind in oestrus produces a secretion described as having a strong penetrating smell. This combines with another sweet musty odour she produces. She will also smell strongly of the stag after mating.
  • Hinds on heat hold their tails high and there can be fights or threats between them.
  • They may try to interest the stag by running past him with head low and neck extended and chewing. On one of these forays the hind may stop and let the stag mount if she is at peak oestrus.
  • She urinates and this excites the male further to drink the urine and lick her vulva.
  • Pregnancy in red deer is from 228-231 days (229 days in fallow).
  • Male offspring are generally carried longer than females. As a result dams suckling males are less likely to breed next season (or will calve later) than dams suckling females.
  • Wild red deer in Scotland on the island of Rhum had about 12 calves in their lifetime when well fed but well-farmed deer should produce more. In farming situation females would be replaced long before old age.
The male
  • Red stags reach puberty between 9-15 months old and fallow form 12-15 months. In the wild a stag does not have the status to set up a harem before about 5 years old, but this depends on competition among other stags.
  • Stags show a definite rut brought on by declining day length in autumn, and in the wild they move to traditional stands where they roar and attract a harem of females.
  • They are at their peak of sexual prowess during the rut but will go on mating and be fertile for about 6 months after. After that they are generally sexually quiet.

Red deer stags in velvet

  • Antler growth is related to this sexual cycle, starting by the male growing velvet antler in spring and culminating in hard antler in the rut. Then antlers are cast before the following spring to restart the cycle.
  • Antlers are not horn. They are laid down as cartilage which is then converted into bone. Antler is one of the fastest growing tissues.
  • Increasing daylight and declining testosterone (the opposite to autumn) stimulates velvet growth. Velvet is rich in blood and is very delicate so stags avoid conflict at this time to protect it. If they fight they rear up and use their feet rather than their antlers.
  • Antlers gain extra tines with age. Young red stags are called "spikers" and fallow "prickets" as they have just one basic antler or spike.
  • Antlers have a number of functions:
  • In the velvet they help to regulate body temperature (a debatable fact).
  • They give off a scent after the velvet antler has been rubbed over the subcutaneous glands under the hind legs.
  • Hard antler is used as tools to dig for feed in snow and mark trees or "threshing" marking of the territory.
  • Antlers enhance social status and are used as a means of recognition by other deer.
  • Damage to antlers or their loss, especially during the rut causes and immediate lowering of status of the stag and he will be quickly challenged.
  • Antlers are designed to lock into another stag's antlers and fighting is really a pushing game to gain status. Stags threaten their opponent during the rut by lowering their heads and pointing their antlers in threat.
  • Only when one stag is weakened can its opponent usually get a side attack and cause serious damage to soft tissue of the body.
  • During the rut in the wild, rival stags may have antler clashes interspersed with a threat display where stags move on a parallel path to each other over short distances, showing their lateral prowess, body size, main and neck, then roaring for periods of 3-15 minutes.
  • This then can erupt into head fights, with the challenger always making sure of an escape route.
  • Castration of males early in life (during the first year) will stop the development of the pedicle from which the antlers grows so the animals end up polled.
  • These castrates are called "haviers", and naturally polled fertile males are called "hummels".
  • Males castrated later when more mature will shed any antlers they have within a few weeks of the operation, and future antler growth will continue for about 4 months after castration.
  • Castrates can develop other male characteristics such as an enlarged neck, mane growth and deepening voice. They can still be dangerous in the rut so care is needed.
Stag behaviour during the roar

Fallow buck in velvet

  • Stags urinate and ejaculate along their bellies up to their chests, and will wallow in mud if they can to attract females with their strong odour rich in pheromones.
  • There is about a 4 second interval between roars, and they do this while carrying out challenges to other stags, going around with neck outstretched.
  • The tone of the roar reflects the stag's social status, so many less dominant stags will not even challenge them and this prevents encounters.
  • Stags herd their harem with chin extended in a threat posture, running around the group of up to about 20 red deer hinds in farmed conditions.
  • Studies on Rhum showed red stags have harems of 6 or more and there is plenty of interchange between harems. The largest harem was 20 hinds. Eighty percent of hinds on Rhum were held in harems.
  • The stag smells the vulva of each hind about every 30 minutes and he also smells the ground where the hinds have been lying. After a Flehmen response he investigates them further.
  • The odours excreted by the hind excite the stag and he starts teeth grinding and tongue flicking. After smelling her urine he will show the Flehmen response.
  • Stags regularly chase hinds trying to mount them while flicking their tongue.
  • The stag guards hinds coming into oestrus for up to 12 hours before they will stand for mating.
  • Young stags from 2-7 years old are unable to defend harems against older dominant stags in the wild. On farms this inter-stag competition is prevented when farmers are selective breeding, and in any case stud stags are too valuable to risk injury through competition.
  • Mating is very quick. The stag pauses for intromission and after a pelvic thrust leaps forward leaving the ground during ejaculation with a near-vertical body posture.
  • After dismounting the stag roars repeatedly, urinates, stands with his head low and then begins to guard the hind again. He may attempt to mate her again in half an hour.
Farmed stags
  • One stag to 50 hinds is an effective joining ratio for genetic improvement, and replacing a single sire every 3 weeks will ensure a high conception rate and reduce the risk of a sire having low fertility.
  • Swapping stags during the rut can be a dangerous management procedure, especially if they have antlers. Antlers should be removed for safety but some breeders selecting for antler production leave the antlers on to show clients the quality of the stag's "head".
  • Stags needed for group mating should be mixed prior to antler growth if possible to allow them to learn to live together.
  • During mating if the dominant stag becomes exhausted, he should be removed to let other stags do his job.
  • Subordinate stags search out females but the dominant stag claims the mating.
Birth behaviour

Hinds before birth
  • In late pregnancy hinds spend more time resting.
  • A few days before calving they become restless and farmed hinds may pace the fences.
  • Some become aggressive and bellow more frequently.
  • The hind's swelling udder and vulva are signs of approaching birth.
  • About 2-22 hours before birth they'll try to separate to the fringes of the herd into a quiet place if possible. This is no problem in the wild but can be one in farming.
  • Hinds prefer high ground for calving, presumably for security reasons.
Hinds during birth
  • With the onset of strong contractions, the hind stops grazing and settles on her birth site alternatively standing and lying down.
  • With heavy contractions she rolls and strains heavily.
  • After the calf is born, the hind may lie for up to 5 minutes and then get up and lick the calf and all excess birth fluids, presumably to clean up the birth site so as not to attract predators.
  • The afterbirth is passed from 2-5 hours after birth and the hind carefully eats this.
  • Birth weights of farmed deer are 7.5-9.5kg for reds and 3.6-4.5kg for fallow.
  • Few difficult births have been observed but mortality is highest is young (above 10kg) calves and those that are very small.
  • Mortality at birth increases with crossbreeding by mating to larger terminal sires (e.g. wapiti x red), and for hinds with their first calf.
Hinds and calves after birth

Fawns like to hide in long cover and are 'planted' there by their mothers

  • After being licked, it takes about 30 minutes for the calf to stand and start to follow its dam off the birth site.
  • The calf seems to be very attached to the birth site in the early days of life, but in farming situations, some do move around more with their dams.
  • Time intervals between birth, finding the teat and starting to suckle vary from 10-130 minutes. The chances of survival drop rapidly with long intervals.
  • After suckling, the calf moves away from the hind and drops down in the grass or bushes to lie very flat and merge with the environment.
  • The dam will graze within about 50 m of the hidden calf and with time this distance is increased to as much as 1km.
  • Studies showed that dams will visit their calves to suckle about 2.8 times/day in the first week, reducing to once per day during week 4.
  • The average suckling times last about 150 seconds in week one, dropping to 50-80 seconds in week two.
  • While sucking the calf moves around all four teats and some sucklings could last up to 4 minutes.
  • Recorded milk intake of fawns was measured and peaked at 1400-2000g/day soon after birth and dropped to 150-630g/day in early lactation. Some well-fed hinds have produced up to 140-180kg of milk in a 150-day lactation.
  • Calves start to nibble grass at 3 weeks old and will graze regularly by 6 weeks of age.
  • Hinds are very alert and nervous as they approach their hidden calves for suckling, compared to their more-relaxed behaviour during grazing.
  • During suckling the calf is stimulated to urinate and defaecate by the hind licking its perianal area. If you rear an orphan calf, remember to imitate this action with your fingers.
  • The hind then eats these waste products and she does this for the first two weeks after birth. She will keep on licking the perianal area for up to 6 weeks after birth.
  • While the dams are with their calves for suckling, the pair may go for very short excursions from 3-30m. When calves leave their dams to go and lie down again, they usually don't go more than 20m.
  • After about 2-3 weeks, calves will follow their mothers and settle into normal herd life.
  • There is considerable social communication in the herd between hinds and calves. Hinds bark at other hinds warning them not to come too close to their lying-out calf. The high-pitched piping notes of the calves are answered by muted mewing-lowing sound of the hind.
  • Fallow does may combine barking with foot stamping and this is very effective in spreading alarm to others. They also lift their tails to expose their underside as another alarm signal.
Handling calves
  • Handling calves, e.g. for tagging has the potential to upset normal maternal behaviour. They may squeal and this upsets their dams that stay about 30m from the handler.
  • If calves are handled during the first two days they "freeze" and their heart beats drop from the normal of 140-170 beats/min to 50-60/min. Normal rates resume within a minute of leaving them alone.
  • After 2-5 days old, calves will run off when disturbed.
  • With newly-captured deer in heavily stocked paddocks with little cover, dams have been seen to take their calves in their teeth and flail them with their forelegs after being touched by the stockperson.
  • If you have to handle calves for recording, do it on the first day after birth and wear gloves which may reduce smell. Some handlers claim it makes very little difference.
  • Force the calf to freeze in the area they were found in. Tag the calf and move away as soon as possible, and record the dam-offspring details later using binoculars.
Effect of human handling
  • Bottle fed deer have been shown to be strongly bonded to their human caretakers, and when tested at 4 years old did not mix with other deer and were more aggressive towards them.
  • Hand-reared deer can become a problem as they mature. They are very big and can be very cheeky and pushy when they have lost their fear of humans.
  • Hand reared stags are a liability and should be slaughtered before 15 months old. They can be very dangerous in autumn and human deaths are on record in New Zealand.
  • Hand reared deer will come to a call up to 1km away. They can be useful as Judas animals to lead others to new paddocks.
  • Weaning a calf from the hind doesn't seem to cause her very serious stress as seen in sheep. Hinds keep up their normal grazing and stop calling for their calf after about 24-30 hours after removal.
Capture and release of deer
  • Being captured is very stressful for feral deer, and individuals vary greatly in the time they take to settle.
  • Capture methods used are:
  • Finding calves at birth and hand rearing them.
  • Building a trap in their territory and attracting them in with feed.
  • Shooting with tranquiliser darts.
  • Bulldogging (leaping on them) from a helicopter.
  • Netting from a helicopter.
  • Mustering with helicopters or dogs.
  • Captured deer may need to be treated with appropriate drugs to counteract stress.
  • Release after capture can be very stressful too.
  • Deer need to be released into a large area to allow them plenty of space, with trees for cover and left undisturbed for as long as possible.
  • After capture their first reaction is usually to pace the fences and then go into cover and sulk.
  • Water should be available and if possible a wallow provided.
  • Don't release newly-captured deer into groups of strangers as they'll be upset and this will stress them even more.
  • Red deer in panic tend to pace the fence and try to leap it from an oblique angle. Fallow run along the fence and tend to run at it head on and burst through the mesh

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