Animal reproduction, oestrus & mating in: cattle, deer, sheep, goats - farmer's role.

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REPRODUCTION: the oestrus cycle, Mating:
                          Cattle, goats, deer, sheep.
 

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Farming

Preparing your stock for Mating:
  Preparation for mating starts well before the daylight hours trigger hormonal changes, in deer, many sheep & goat breeds. 
Working males need to be in good condition and health before the start of mating.
Healthy strong legs and hooves: The males will do more walking than  usual.
Their back legs take all his weight when he mounts. Select males only with strong legs, and very healthy hooves. 
Libido: He need to be keen to do "his job". 
Good condition is essential: He may have to challenge (fight off ) competition from other males in with "his girls".
The urge to mate is so strong in a "good worker", and this good worker will work often at the expense of his usual "stomach full" of feed.
He must be disease free:  Get him checked out.. You can ask about his health history if  buying, or leasing an animal.
Better still you can get blood tests done by the vet.

The BIGGER his scrotum:                                                                            
Its so true!!!     Size does matter.
  The bigger his scrotum, the more sperm he can produce.
 
Furthermore: Daughters from dads with large scrotum will have better fertility than daughters from  Dad's  with less... 
When breeding: Make good use of that generously endowed sire.
 Group of rams for sale at a "Small Farmers Auction". They weren't posing.. they were trying to flee. >
 
  * Cows, ewes, hinds, does:                                                                                           
All animals need to be in very good condition prior to mating.
Ideally they should have plenty of food ahead of them in their rotations.
Animals not cycling can be the result of poor nutrition. Consult a vet. Cows can be treated for non cycling.


The OESTRUS: ("on heat" /the hormonal cycle - "how it works")
The Hypothalamus:
This is situated in the brain. The hypothalamus receives signals from the brain that conditions are ideal to start the oestrus cycle..
The hypothalamus then stimulates the anterior lobe of the Pituitary gland to produce Follicle Stimulating Hormone. (FSH)
Follicle Stimulating Hormone (FSH):
Acts to start the development of a follicle in an ovary.
(a graafian follicle) The follicle contains an ovum.
As the ovum matures, the cells of the follicle secrete oestrogen.
Oestrogen:
Oestrogen is responsible for the "on heat" behaviour. Oestrogen prepares the uterus for implantation.
When the oestrogen blood level is high further secretions of FSH are stopped, and the pitutary gland then releases Leutinising hormone(LH).
The ratio of FSH, to LH levels actually triggers ovulation.
Ovulation:
The ovum/egg is released.

Leutinising hormone
(LH):
Effects the development of the graafian follicle.
After ovulation LH transforms the follicle cells into a clump of yellow tissue. This clump of yellow tissue is called a corpus luteum.      
The corpus luteum:
Then becomes a new endocrine gland secreting progesterone.              
Progesterone:
Supresses signs of heat. It prepares the uterus to accept the fertilised egg.
A high blood progesterone level prevents further action of the gonadatrophic releasing hormone (GnRH) This blocks LH and FSH.
Implantation:
If fertilisation has occured, the fertilised ovum attaches itself to the uterine wall. If Pregnancy does not occur: The uterus produces prostaglandin.
Prostaglandin:
Dissolves the corpus luteum, and then the progesterone levels fall. The GnHR gonadatrophic releasing hormone then becomes activated.. then FGH is released... and the cycle continues.

 On heat / oestrus  the Behaviour: 
Allogrooming:
This is when animals spend time licking each other.
Hinds and stags, and to a lesser extent cattle, may spend time allogrooming as part of their mating behaviour.
During mating, the allogrooming animal is usually in search of pheremones. Cows and hinds allogroom their young.

Flehman:
Cow (right) has a flehman expression.  Flehman is used by ruminants to detect pheromones (sexy smells) in the air:
 The animal stands still, and has a "studying" appearance.  The head is held upwards.   IN order to sample the odour's in the air, their mouths will be slightly open.  Sometimes  their lips are curled back.
The cow photographed (R) is in a group of cows.
 She is  using the flehman expression to detect  female pheremones within the group she is in. .. She is on heat.

P
heremones:

Pheremones are "sexy odours. They are produced by one sex, to attract (or "turn on") the opposite sex.
With cattle both sexes notice the females pheremones.
The odours produced by Rams, Stags and Bucks will start the females oestrus cycle.
 
 
                                                                                              
Mating: (Rams, Stags, Bulls and Bucks)
Natural Mating:
Any healthy keen working fertile male will do.
Furthermore there is little work involved for the farmer, other than noting the mating dates.
It may cost to buy or lease a suitable sire.

Breeding to improve traits: 
For example:
 
Milk production, mothering skills,  fertility, temperament of your animals.
Or improve antlers, fleece, weight, and their ability to gain weight, or any other traits.
You could purchase: A sire who has sons, daughters with the characteristics you hope your herd/flock will obtain.
Be aware that not all traits are so heritable.
Check out his history from his owner before you enter into a deal.
Get him checked by a vet to make sure he is disease free.

Artificial Insemination:
Talk to your local semen sales person about A.I.ing,
The sires you choose will have information about them, their traits, and the traits of their offspring.
There will be a charge for the technician. There will be extra costs if you choose to synchronize mating.
(Synchronizing has it's advantages ..
They will come on to heat about the same time for mating..But the offspring will all be born about the same time, so there could be some confusion when the young are born, and perhaps some mis-mothering.
The price of semen can vary, sometimes the price of semen is related to the availability of semen, rather than the quality of the sire.

 Stock Improvement: (Breeding Values)
  The young receive their genes from both of their parents.
Some traits are more heritable than others.
In New Zealand the terms: "Estimated Breeding Value" (EBV) or Breeding Value (BV) are used.

How stock improvement works:-
Your cow has an estimated breeding value of say "1". She is mated to a bull with an EBV of say "9"
The resulting calf will have a breeding value of "5" (Half the total of the parents breeding value)
If, say, the cow has non identical twin daughters.
Both daughters will have the same breeding value. However their traits may be different.
By keeping the animals with the traits you desire in your herd, and culling out animals that are not up to your standards. By continually using superior sires with the traits you want for your replacements. The genetic merit of your herd/flock will increase. So will the market value of your animals.

Plan the  parturition date to fit in with pasture growth.
In most farming systems the young are born when there is plenty of feed available.
Lactating mothers must have sufficient feed to maintain their body condition, and provide milk for their growing young.
The females need a reasonable body condition to be able to cycle.

Maturity/Puberty:
It is a wise idea to separate young bull calves from young heifer calves before they reach 4 months old.
The actual start of puberty is influenced by species, breed and nutrition.

(You may have heard the word
"Freemartin":
When twins are born..If one twin is a bull, the other a heifer , then very very likely the females will be infertile.
This is because the development of her reproductive organs is not complete.
Bulls however are usually fertile. )

 A calf a year:
The cow is expected to calve every 365 days. The gestation period is  282 days.
As she will possibly be lactating (being milked or feeding a calf) during the mating season.
 She must have a diet to:
Maintain a good condition, produce milk. The nutritional needs of a  lactating cows are very high.
There is an interval after calving of about 7 weeks before she starts to cycle again.
Some farmers mate their yearlings a week before the rest of the herd, as this age group take a little longer after calving (usually about 8 weeks,) to start cycling again.

Cross breeding:

Firstly: If  considering cross breeding consider the cow that has to push the calf out.
Some breeds are known for easy calving. Some breeds have big calves.
  Do NOT use a "Goliath" sized sire over a "Tinkerbell" sized cow.

1st calvers: 
Will really benefit from very easy calving. Throughout their pregnancy they are still growing. Jersey's bulls are a popular choice to use over dairy
breed 1st calvers.  Cross breeding has advantages. First crosses have often proved to be more profitable because of a hybrid vigour.
Angus - Herefords are popular beef animals. New Zealand's most popular dairy cows are the cross breed Jersey X Friesian.
These animals are in demand because of their high  milk-solids production.

Artificial insemination:
Advantages and disadvantages of artificial insemination:
Farmer time:

 
You will need to identify cattle that are on heat.
You will also need to yard your cows ready for insemination.
On the other hand, artificial breeding in cattle is simple in comparison with other species.
The price is not daunting.
You get the opportunity to choose the bulls, and the traits they can pass on.
PROVEN bulls will have fathered many sons and daughters. Information on them, and that off their offspring is recorded. You will have a good idea of the traits you can expect in your future calves. You wont need to spend money buying an expensive bull for trait improvement. You may need a bull to use over cows who fail to get in calf to Artificial Breeding (AI).

For Successful Artificial Breeding:
Make sure semen, and the technician are organised well before the start of mating.
(Usually the technician will visit you prior to your "start of mating" date. Take the opportunity to ask lots of questions.
     Having all your herd cycling, and being able to identify cows on heat is the ideal. 
At about 4 weeks prior to the start of mating, dairy farmer's tail paint their cows.
I like to apply the tail paint thickly.
No trimming the ridge of hairs.
This shows up as being flattened if there was little activity out in the paddock. Usually though, it will be dirty, and possibly skin and hairs will have been removed.  
Prior to the start of mating:
Get the vet to check all cows who have the original tail paint intact.
(Include any cows you are not sure about.) The vet will examine and treat those cows. They will come on heat during mating, and will be fertile.
At the start of mating tail paint your herd with a second (another) colour of tail paint.
 Keep a record of: When the cow comes on heat, and off course when mated.
**
After they have been mated apply the 3rd colour of tail paint.***
This will give you a "picture" of how your herd is going. And how many of your cows (possibly) are in calf.
Heat detectors: are a handy tool.
I have used them successfully to identify our on heat 1st calvers. "Kamars" are more sensitive to the weight of a riding animal, and their
colour change is very noticeable.  After mating either apply another kamar, or apply tail paint.

Being calm and quiet is SO essential when dealing with your on heat animals:
If your animals are unfamiliar with your yards, give them the opportunity to become familiar with the yards before mating starts.
Avoid isolating an animal: Cows don't like being separated from their mates, so have several other herd mates along for company when yarding them.
If you choose to gather your on heat animals from the paddock and then walk them to your yards.
Give yourself plenty of time and very quietly walk with them to the yards.
If only one animal is on heat, bring several of her mates to the yards with you.
At the start of mating in a group of cows there will be a lot of mounting.
As the weeks of mating go by, hopefully most cows will be in calf, and fewer cows will have the urge to mount. This means that a cow on heat could be missed.
Bulls however do a great job of heat detecting. Farmers put a bull in with the herd, after 3 weeks, or 6 weeks of artificial breeding.

 Oestrus/ on"Heat"  & bulling behaviour in Cows:
There are 3 stages of oestrus /"on heat" in cattle:
The usual length of oestrus is 14 to 15 hours. Some cows may have a silent heat as their first heat when they start cycling.
You may not be aware of a silent heat as she will not mount, nor tolerate attempts to be mounted.

"Coming Into Heat".  (Early Heat)  
T
he animals in the photo  were restless.
Note the sniffing, and how close they are together.

There is often  a bit of pushing and shoving.
She may have smelt pheremones, and may search for them (smelling, or licking in the under the tail region of another cow, or may sample urine from a cow) 
She may rest her chin on the tail-spinal area of a cow in front of her.
If the cow straightens her spine, the behind cow may mount. (the front cow is on standing heat.)
Mounting cows:
 It is the early oestrus cow that does the most mounting.
Older cows can be quite vigorous.
Some cows are very dramatic: It's just their style.. it is not an indication of how "on heat" they are.
The "early in heat" cow will NOT tolerate attempts of being mounted, and they will NOT stand to be mounted.
Lactating cows may withhold their milk. If you study her closely her vulva may appear swollen and reddish.
 

"Really On" (Mid Oestrus) "Standing Heat":
Sexually active group:(SAG):
In a group of on heat cows you'll observe mounting behaviour, attempting to mount, some head to head mounting, quite a bit of urine sampling, some allogrooming, chins resting on the tail head, and flehman.
They're having a very busy time.  They wont spend their usual amount of time eating. A cow may stand perfectly still, then urgently rise to mount the cow in front.
An isolated, or tethered cow's behaviour may change somewhat.
They may continually  call out a lot. Prior to mating note the date of her heat so you have an idea when to expect her to come on heat again.

If she stands to be mounted she certainly is in "mid oestrus" (standing heat).
Possibly her vulva will be red, and moist. She may withhold her milk.
A string of clear mucus may be visible from the vulva. (Also called a "bulling slime".) This could be twisted around her tail, or smeared across her back due to her being mounted.
Older cows may have very dramatic "on heat" behaviour.
The skin over any bony areas near her tail can be completely rubbed off.
The weight of mounting cows will certainly alter the tail paint. If not rubbed off, it will be flattened. 

By placing your hand on the tail part of her spine, and pushing down..
You can observe if the cow straightens her back in preparation for taking the weight of a mounting animal. Straightening her back is an indication that she is in standing heat.
I
n a SAG the herd hierarchy system vanishes.
Lower ranking cows mount higher ranking cows. The urge, to ride in fact is so dramatic, I've witnessed an older cow with an injured leg repeatedly mount her herd mates.
Concrete surfaces, especially covered with dung can be very dangerous for on heat cows. Eating is not a priority in Mid oestrus.
"Going off" (late oestrus)
You notice that she may have some mud and dung over her body.
The tail paint, plus skin under, plus the skin over bony prominences in the tail region will have been rubbed off. This is especially so if she has been on standing heat for a while. (Older cows in particular) Those with very short heats.. the tail paint may just be dirty, or squashed down.
She may still sniff other cows.
She may have a clear mucus discharge, (sometimes referred to as "bulling slime) or it could be smeared across her body. 
Gone are any loose hairs  from the back of her body.
She will NOT tolerate another animal attempting to mount her.
But, she is now more relaxed. Her appetite returns.
* * * Caution here:

When the grass is at its lush stage. She will compensate for the lack of feed when she was on heat, and may gorge.
Ingesting a huge quantity of lush grass, can lead to bloat. Ensure these cows are drenched for bloat.

The cows (above right) wait calmly to be inseminated. They are in late oestrus.

Silent Heat: Occasionally an "on heat" cow will not demonstrate "on heat" behaviour.
http://www.nadis.org.uk/DiseasesCattle/Oestrus%20not%20observed/OESTRU_1.HTM
When to inseminate.

Once the egg has been released it will stay viable for 6 to 8 hours.
The semen undergoes a preparation before it is capable of fertilising an egg. This takes 4 to 6 hours.
Unlike the bull who releases his semen into the vagina, the technician releases the semen into the uterus.
The semen must swim to the oviduct to fertilise the egg.
Semen can survive in the uterus for 24- 48 hours.
Ovulation occurs 24 hours after the start of "on heat" or 8 to 10 hours after standing heat stops.
Inseminations are best carried out in late standing heat.
If the same cow happens to be on heat the next morning, then re-insemination, using the same bull's semen is recommended.
(This removes any confusion as to who the sire is.)


How does the A. I technician do it?:
The farmer chooses which straw/bull to use. The technician extracts a straw of semen from the sperm bank. The technician will write down the bull ID number next to the cows details in the recording book.
The technician, after thawing the semen, then places the straw of semen into the end of the pistolette.
The technician wears an above the elbow plastic glove, which he has generously lubricated. Into the AI yard the technician takes the pistolette loaded with a straw of semen, and a tissue for wiping clean the cow's vulva.
Cows on heat don't usually object to the technician's interference.
In the photo the technician has placed the tissue (after use) on the side of the cow.
Using his left gloved hand he inserts his hand into the cows rectum. He then pushes his hand forward to
help locate the cows vagina.

 T
he pistolette is then inserted into the vagina. Using his left hand the technician locates the cow's cervix through the bowel wall. Once the cervix is located the technician grasps it firmly with his left hand, and using his right hand he manoeuvres the pistolette in through the cervix. The technician then releases the sperm.
Is this cow ready for insemination?
There are advantages of studying the herd for on heat activity during the day, but a lot of mounting behaviour may "go on" in the early hours of the morning. If in doubt as to if she is ready or not: Look for a clear mucus discharge from the vagina. An unusual amount of sniffing especially at other cows. Does she withhold her milk? Study her behaviour with a group of bulling cows. If still in doubt:If you inseminate her it will cost you the straw of semen. If you don't inseminate her, and she was on heat, she may not get in calf for another 3 weeks.
If there is a chance that she could be in calf:
If you think she could be in calf, and yet her behaviour suggests she's "on heat". You can put her with the bull. (he wont harm her)
Tell the technician that she could be in calf. The technician will then release the sperm just inside the cervix so it can't damage a pregnancy.


Mating & the bull:
T
he sight of a bull may "kick start" some cows into the hormonal changes essential for oestrus.
A bull is clever enough to know when a cow is about to come on heat. He may even guard her.
Sometimes he has to manage cows of different sizes. I have observed an adult bull position himself with great accuracy when naturally mating a smallish shorter cow.
I have seen young bulls stand on the tips of his toes (so gracefully) to mate with an adult cow.
Avoid giving young bulls too many adult cows to work on as it can be a bit hard on their hooves.
Virgin bulls that have seldom mingled with cows may not know what to do when required to work. (Over winter my young bulls shared a paddock with the in-calf cows. ~It could be luck, but all my young bulls went eagerly to work when introduced to "on heat" cows in late spring.~.

Mating Yearlings:
Dairy replacement heifers are frequently mated at 15 months of age.
At this age they are expected to cope with a pregnancy, plus growing and gaining weight.
Weight (average) at 15 months;
Jersey 220 kgs, Jersey X Friesian: 260 kgs, Friesian 290 kgs.

You have three choices when it comes to mating your heifers:
~ an easy calving will help your animals off to a good start.~
Heifers "run with bull":

For those unfamiliar with that term it means letting the bull in with the heifers for mating. Abbreviated as: "RWB. It is the most common way of getting 1st calvers in calf.


this group of yearlings have been tail painted.
A young lightweight bull is amongst them.
Several of the group seem to be on heat, and are "riding" herd mates. A lot of riding and trialing goes on.. Basically yearlings are lighter, and heat detecting is not as easy as
heat detecting with mature cows.


Artificially Inseminating your heifers:
It is the quickest, and least expensive way of DRAMATICALLY increasing the genetic merit of your herd.
Presuming your yearlings are the best genetic merit animals in your herd, then by using a "top bull", the resulting calves will be of even better genetic merit.
This will also improve the $$$ value of your herd.

AI any heifers on heat:
You may choose to observe which animals are on heat and bring them in for insemination. Kamar heat detectors work well, because these animals are lighter, and they don't ride as aggressively as older cows. My heifers were hand reared, and were a placid friendly herd. Each morning during the mating season
 I would  observe them, and look for heat detectors changes. I would then gently "*manoeuvre" any "on heat" animals out of the gate. I then quietly walked them up to the yards. After mating we applied tail paint.
*Manouver... It is important to work with these young on heat animals as calmly as possible.

Synchronised mating:
There are several advantages in synchronising: The main one, is you don't have to heat detect each day, and you don't have to yard the animals each day for insemination.
You will have to yard them for treatments. It is the most expensive way of getting animals in calf.
Whatever method you choose, a bull may be needed to "finish" off (mate with animals that failed to get in calf.) Synchronising is usually organised through your local vet, and the semen salesperson.

There are several ways to synchronise your animals.
The vet will explain, and possibly have information about the method printed out for you to study.
The vet will insert a CIDR's (or PRID's UK) into the cows vagina. These devices release hormones, that are absorbed through the mucous membrane wall of the vagina. These hormones manipulate the animals cycle. If you synchronise a large group of animals, then expect them to calve within several days of each other. There could be merit in splitting the herd up into several manageable groups just for calving.

Cow's cycle, and Gestation length.
Cows: cycle every 21 day:  (range: 17 to 24 days)
The average length of a pregnancy (gestation length) is 282 days.
To roughly calculate the calving date: Count 9 months and add 10 days

Helpful link to many cattle and farming sites: http://www.KwMap.com

Sheep and Goat 
Have several things in common.
The odour from bucks and rams will start oestrus in the females.
Frequently the first heat is a "blank" ..But the next heat she will be fertile.
Most goat and sheep breeds are seasonally polyoestrus meaning that these animals only cycle during the breeding season.
It is the length of daylight hours that trigger the start of mating.

Refer to: > The Sire: (Rams. Stags, Bulls, Bucks)

About mating your Goats
Prior to mating: Purchase, or organise leasing or borrowing a suitable buck.
When shopping around for a suitable buck remember: Go for the buck with the bigger scrotum.
 Choose one in good condition, good health and with strong  legs.
 You can check out his health and reproductive history.
His hooves,which must be strong and healthy will appreciate a trim prior to mating. 
Drench all your stock prior to mating.
Your does:
They must be over 10 months old. They should be in good condition, and be already drenched and wormed.
Does do not cycle after giving birth until the next breeding season. The odour (pheremone) from a buck will trigger oestrus activity in the doe. Some does will have a kid at foot until the next ofspring is born.
Sperm production, and the rut:
Although influenced by the animals nutrition, and the day length, bucks produce sperm continually; the unused quantities being voided in urine. In late summer and autumn (when the days get shorter) the bucks begin to peak in their reproductive behaviour. Their blood testosterone level is high, and their sebaceous glands produce the buck odour. This odour starts the hormonal cycle in does. She may not be fertile the first time she cycles. This period, is called the rut. Bucks may fight with other bucks.
Does and their oestrus cycles:
The goat breeds differ: Some breeds will start cycling when the days shorten, and others when the days are longer. Boers have an extended breeding season, and can manage 3 kiddings in 2 years.
The oestrus cycle in does occurs at 15 - 24 day intervals but only during their breeding season.
The on heat stage can range from 8 hours to 60 hours.
How does behave when they are on heat:
Some does show very few "on heat" signs. This makes it difficult for humans to identify some "on heat" does.  Others can exhibit all, or nearly all the signs. 
These signs are: She'll mount other does. She'll allow other does to mount her.
She will call out. She will wag her tail sideways. (termed flagging)
She will urinate frequently leaving small quantities of her pheremones (in the urine) in lots of places.
You may note a mucus vaginal discharge. You may observe that her "bottom" is swollen, and pinkish.
You may notice that she is not eating as much as usual. (She has other things on her mind.)
Buck and the Doe:
A buck with sample the odours in the air. (flehman expression)
He  hopes to identify the pheremones of an on heat doe.
Once the on heat doe has got his attention she will then entice him to follow her around the paddock, or the enclosure. The doe will be on standing heat for mating to occur.
The buck throws up his head when he ejaculates.
Ovulation occurs a little later, allowing the sperm adequate time to move from the vagina and into the oviduct where fertilisation occurs.
Ovulation rate:
1 or 2 ova are often shed at ovulation. (3 or more is not uncommon.) This is called the ovulation rate. Improved nutrition has been known to increase the ovulation rate.
Artificial insemination and embryo transfer:
The use of AI with fresh or frozen semen is now as well established procedure for goats, as are embryo transfers.
Ovulation Goats cycles and gestation:
The average of goat oestrus cycles is 21 days.
The gestation length varies with the breed. Saanens, Boers, and Alpine goats have a gestation length of 150 days. Toggenberg about 152 days. The number of previous pregnancies, the number of foeti influence the actual length of the pregnancy.
To roughly calculate the estimated kidding date: Count forward 5 months.
In non-seasonal breeders the abundance of good feed may start the doe into oestrus and ovulation. In cycling females improved nutrition can increase the ovulation rate, resulting in a higher incidence of multiple births.
More information on goats: http://www.caprine.co.nz

Sheep: Preparation for mating (tupping)

Purchase your rams several months before the start of your breeding season. Your new rams should be fit, fertile, and free from disease. You can have blood tests done by the vet to rule out any diseases, especially diseases that can be passed on. Your ram needs to be a keen worker. His hooves must be healthy.. they're going to do a lot of work. Choose the ram with the bigger scrotum.. You can always measure the circumference of his scrotum. Bigger means he's more fertile.
Hot Weather and his fertility:
The scrotum is situated on the outside of the male mammal body for a very good reason. It is much cooler on the outside, than being squashed in with all those other organs.
If the weather is too hot , a temporary infertility can result. The heat of the day is a concern in very hot climates. Large trees can provide shade. Shearing several months before the start of tupping if often done in New Zealand to help the ram feel cooler.
The Ewe:
Her condition at mating can influence her ovulation rate. As the ewes body weight increases above a certain weight, so does the percentage of multiple ovulations. A healthy ewe who is gaining weight is more likely to have more eggs released to be fertilised, than a ewe loosing weight. Most ewes are first mated at 18 months of age. The sucess of the mating is greatly influenced by her nutrition.
Prepare your rams and ewes:
Ear tag all your stock. Make sure they are up to date with vaccinations and drenches. (especially those internal parasites) Your local vet will have knowledge of the soils in your area, and what minerals they lack because of your soils. Administer any minerals that are needed. (selenium and Vit E levels are often quite low in NZ soils)
Cull out any animals with diseases, poor udders, or old animals.
The Ram (or buck) Effect:
The presence of a smelly pheremone laden ram is a turn on for the ewes. This odour starts the ewe (ewes) hormonal cycle. Once she is on heat she will then start her 17 day cycle. She is seldom fertile during the first heat. Ewes can be on standing heat for 24 - 36 hours.
Ewes may not be obviously on heat to the farmer, but the ram will certainly notice.
Teaser Rams:
Teaser rams are vasectomised rams. They are not fertile, but they behave like rams.
Often these rams are put in with the flock to start the ewes cycling.
The teaser rams are then replaced by a fertile ram when the ewes are cycling and more likely to be fertile. Once mating starts, keep and eye on the activities in the paddock. Remove any boss rams.
Ram to ewe ratio: This could depend on the size of your paddock. In a very large hilly paddock you could use an extra ram. Basically you could use 2 rams for every 100 ewes. Consider rotating your rams.
Marking Ewes. By using a harness with a marker on your rams you will have colourful evidence that he is performing. By changing the colour at 17 day intervals, you will know if your ewes are cycling after having been mated.
Ewes gestation, and cycle length:
Ewes have a 17 day cycle.(average..they range from 14 to 19 days)
The gestation is 149 days.
To calculate the estimated lambing date, count forward 5 months.

Deer: Mating Deer (general):
There are many breeds of deer and many more hybrids.
Deer are seasonal breeders. The stag/bucks hypothalamus responds to the shortening hours of daylight by stimulating the anterior pituitary gland to produce follicle stimulating hormone. (FSH). The FSH stimulates the manufacturing of testosterone (in the testes) His blood testosterone level increases dramatically.
His behaviour changes dramatically. You may notice a thickening around his neck.
The rut now dominates his behaviour. He will communicate challenges, or brag to other stags..(You may hear these as a "roar", "bugle", "screech" or sort of a whistle.. the different breeds make different noises) Some stags/bucks will leave their pheremones in locations where hinds often pass, or gather.
The hind/doe/cow behaviour becomes mating orientated. She will be aware of the the pheremones left by the male, and may leave some of her own around.
Does/hinds really need to be in good condition so they will start cycling, and feeling along the spine, and the pelvis bone will give you an indication of her condition.
The rut starts in Autumn. The actual start date varies with the breed, the climate, and the geographical location. The timing of the rut means the young are born when there is plenty of feed.
The calved doe/hind/cow needs adequate feed as she feeds her continually growing young, and maintains, or increases her own body weight.
Farmers may do a cull of surplus animals prior to the rut.
Many farmers let the stag in with the does/hinds prior to the start of mating, so these groups can adjust to each other. The two sexes spend time together. They will lick, and sniff each other.
When she is on heat, he will chase her. (in the wild it is actually the female who chooses which stag she will mate with.) After several mountings, he will then mate her.
Dont use large breed sires over small sized deer.
Mating (natural, or artificial) should be as stress free as possible for the deer.
Avoid disturbing a group during the rut. Stags can be dangerous during the rut.
Red deer:
The males are called stags, the females hinds, and the young are called fawns.
An adult Red deer stags can be about 1.2 metres high at the shoulders.
The hinds can be mated as young as 16 months old. This younger group are mated separately from the adults. Red deer are normally silent, but during the rut they become quite noisy with their bleating and grunting.
A ratio of 1 stag to 40 - 50 hind is ideal.
The oestrus cycle is 18 days. Gestation is 225 - 245 days.
Wapiti /Elk:
The adult bull, (the male) stands at 1.5m at the shoulders.
Females are called cows, and the young are called calves.
Gestation: 236 - 246 days. They are actually in the same deer family as red deer. Their mating behaviour is very similar to that of red deer.
One bull can service 20 - 30 cows.
Fallow deer:
The females are called does, the males are called bucks. The young are called fawns.
The adult bucks are seldom taller than 90 cm at the shoulder.
Their antlers have flattened areas..rather like moose antlers.
Their oestrus cycle is every 22 days.
They are a very flighty breed in comparison with red deer.

Prior to Birthing:
Deworm and vaccinate your stock.
Red deer in New Zealand are usually set stocked for calving rather than being shifted around as in rotational grazing. In each paddock have a group of prevcalvers, perhaps you could group them according to their calving date. These paddocks should have adequate feed, plus plenty of shelter, and a good water supply.
The plan is to keep an eye on your stock , and interfere only if really necessary.
The breeds (and hybrids) vary somewhat with their pre birthing behaviour.
All hinds/does "bag up" prior to calving, meaning that their udders will be shapelier and will appear fuller. Some does/hinds may seek out a sheltered place to give birth. In several breeds the hind may start pacing along the fence line as birthing approaches.
She may sit down, roll on the ground, stand up again, during her labour.
The fawn in a singleton pregnancy normally enter the world in a "diving position". 
i.e. The two front legs appear first.
You can check that the soles of the hooves are towards the ground.. use binoculars if necessary.
If she is having problems, and you cannot help .. dont hesitate to call the vet. You can learn a lot from your vet.
After the calf/fawn is born she attends to washing the newborn. This helps with bonding, and it clears membranes, and fluids from the face. The fawn then begins to attempt to stand, (very shakily at first.) It heads for its mother udder,and may be nudged in that direction by its mother. The infant then has its first drink of milk..colostrum.
If humans interfere around this time, the mother may abandon its fawn.
Usually the placenta, membranes, and any fluids around the birthing area are eaten by the dam.
Artificial Breeding in deer:
Certainly worth considering if you wish to improve the traits in you herd.

These websites may be helpful:

http://www.deerfarmer.co.nz About deer farming & the  industry in NZ.
http://www.deertracking.com (Canadian) Has some helpful information, and a discussion forum.
http://www.diaa.org/  The deer industry in Australia. Use "deervet" for answers on deer health.   
http://www.deer-forums.com Deer & Wapiti/Elk farming. It has a helpful discussion forum.
http://www.quanez.co.nz/fallow/news/ Fallow deer farming in New Zealand.

 Glossary
Anoestrus:
The oestrus cycle is dormant.
CIDR: (Controlled Internal Drug Release) The CIDR releases progesterone. When it is extracted the progesterone blood level drops. This then results in another egg developing, and the animal comes "on heat"
Conception rate: The percentage of animals conceiving.
Corpus luteum: (or Yellow Body) After ovulation, at the base of the ruptured follicle glandular tissue starts growing. It continues to grow until it protrudes from the surface of the Ovary.
It is the corpus luteum that the vet 'feels' when assessing if a cow is cycling or not. The corpus luteum acts as an endocrine gland and produces progesterone. The corpus luteum dies if fertilisation does not occur.
Endometritis: Infection of the endometrium, (the lining of the inside of the uterus.) Pus present in the vaginal mucus during heat is a sign of this infection.
Estrogen: oestrogen: It is a collective name for 3 closely related steroids. (estradiol,estriol estrone) It is secreted from the developing follicle in the ovary. It is periodically topped up by the FSH.
Harem: Deer naturally breed this way. A stag will "hold" a group of hinds in order to breed with them. He may be challenged by other stags.
Implantation: Refers to the attachment of the embryo to the wall of the uterus.
Libido: Sex drive. Desire to mate.
Lutenising hormone: (a gonadotrophin) Manufactured by the pituitary gland. In females stimulates further development of the egg and its release from the ovarian follicle. It also stimulates the growth of the corpus luteum..
Follicle: Where a ready to shed egg is contained. It is a small fluid filled sac on the surface of an ovary. The follicle bursts releasing the egg.
Follicle stimulating hormone: (a gonadotrophin) Made by the pituitary gland. In the female the FSH promotes the growth of an ovarian follicle.
GnRH with prostaglandins: Used in synchronising timed heats. It can be used to increase the fertility of cows. NRR (non return rate) This refers to the number of cows that did NOT return to oestrus after insemination.
Oviduct: In female humans it is called the fallopian tubes .The egg moves from the ovary to the uterus in the oviduct/fallopian tube. In this tube fertilisation usually takes place.
Ovulation rate: The number of ova released at ovulation.
Puberty: Is the age when mammals become sexually mature. The age
When the oestrus, or the menstrual cycle begins.
Pheremones: Sexual Smells that attract the opposite sex (except for cows)
Pituitary gland: A small gland at the base of the brain in vertebrates. It produces hormones that control other glands and influence the growth of the bone structure, sexual maturing, and general metabolism.. In humans it is the anterior lobe that is responsible for FSH and LH Progesterone: A sex hormone produced by the corpus luteum. It maintains a pregnancy.
Prostaglandin: (PG)A hormone manufactured in the uterus. It dissolves the corpus luteum, causing the progesterone level to fall. It Is used to treat uterine infections. If your bull has jumped the fence an mated your neighbours prize cow.. the vet may administer prostaglandin to abort a pregnancy.
Pyometria: The result of post calving endometritis. The uterus is full of pus. Prostaglandin is frequently used to treat this. It brings the cow into oestrus, and the uterus empties.
SAG: "Sexually Active Group"  "on heat" behaviour in a herd of cows. Where a group of 'on heat" (oestrus) cows will group together. Within the group, they'll odour sample (for female pheremones) they'll allogroom, A lot of smelling, and mounting each other goes on in the group.
Teaser ram/bull/stag/ buck: These males have been vasectomised. They have all the urges, and behaviour, but, as the vas deferens has been cut and tied. They are sterile. In sheep and goats they can be used for the "the ram" effect. Teasers may be used in deer and cattle to identify on heat females ready for artificial; insemination.
Testosterone: A Male hormone.