The Dairy Cow: A Great Provider
The dairy cow spends most of her short life calf-bearing and producing milk. One of the few high points in her routine comes in springtime when she is turned out of her winter quarters to graze on the lush green pastures outside.
Turn-out time, as farmers call it, is a marvellous moment in any stockman’s calendar. In addition to signalling the end of winter, it is a joyful sight. The cows, shut up inside sheds for months, are at last led into the spring sunshine. They sniff the fresh air and immediately show their delight by galloping into the fields, bucking and jumping like young calves.
Often, it is necessary to line up a few people in front of the field’s boundary, to restrain the over-excited animals from tumbling into a fence or ditch and injuring themselves. Within half an hour or so, these great half-ton beasts have sobered up and regained their bovine dignity.
Depending on the weather and the geographical location of a particular farm, cows are turned out in April or May. The farmer’s objective from this time until the onset of winter in October or November is to ensure that his cows have as much access as possible to home-grown grass or forage crops.
The daily routine
Once at grass, the cows quickly settle into a pattern of grazing, ruminating and idling. This is repeated continuously throughout a 24-hour period.
Milking takes place twice a day – in the morning and afternoon. The best milk yields are obtained if the interval between milkings is as even as possible. This is why herdsmen have to get up so early in the morning. They may not enjoy the experience, but a 5am start usually means that the afternoon milking can be finished in time to leave the evening free.
After the morning milking, the herd is turned out to grass and without exception the cows begin grazing. Before coming in again for the afternoon milking, each cow has spent between three and four hours grazing, three hours ruminating and the rest simply idling — the nearest a cow gets to sleeping.
Grazing cows may consume as much as 70kg (nearly 1-1/2 cwt) of fresh grass a day. A typical Friesian cow yielding 20 litres (41- gallons) of milk a day will require about 40 litres (9 gallons) of water to drink each day — equivalent to a bath tub full of water.
This is not so surprising, as milk is 87% water. It follows that the higher the milk yield from a cow, the higher its intake of water.
A question of breeding
The principal milk production regions in the British Isles are north-west and mid-west England, the lowlands of Scotland and south-east Ireland. It is here that the strongest concentrations of dairy cows are found and more than 90% of them are Friesians.
There are good reasons for the supremacy of this breed. The average Friesian cow yields 400-500 litres (around 100 gallons) more milk per year than does the Ayrshire, the next best breed. The pure-bred Friesian is also unique among dairy cattle in that the calves can easily be reared as a prime beef animal.
The remaining 10% of British and Irish dairy cows are mainly made up of Ayrshires, Dairy Shorthorns, Guernseys and Jerseys.
Ayrshire cattle, as the name implies, are found in greater numbers in Scotland, but they are also kept in the north of England, especially on the west coast. Elsewhere they have generally been superseded by Friesians.
The Dairy Shorthorn originated in the north-east, and was the commonest breed in that region until about 25 years ago when it too fell victim to the Friesian invasion.
Guernseys and Jerseys are still of course strongest in the Channel Islands, but they are also widespread in the south of England.
Less numerous breeds include the Gloucester, Dexter, Kerry and Red Poll. One hundred years ago, the Kerry was the dominant breed in southern Ireland, but now it is mainly restricted to the extreme south-west.
Life cycle of a dairy cow
The average life span of the dairy cow is about six years, the last four of which are spent bearing calves and producing milk.
Most dairy cows calve either in the spring or autumn. The advantage of spring calving is that the cow is at the peak of her milk production when she is turned out to grass. Because the ‘spring flush’ of grass growth is highly nutritious, the cows milk better at this time than at any other.
For many years, winter milk prices were made more attractive, in order to even the production of milk throughout the year. Those farmers who chose to calve their cows in autumn had the advantage of better milk prices. But in recent years all this has changed.
A cow is mated with a bull or artificially inseminated at about the same time each year. Towards the end of her nine-month pregnancy, she is ‘dried off’ — encouraged to stop producing milk by milking less and giving less water — and put in a separate field from the rest of the herd. These few weeks are the only respite she has from milk-producing during the course of her working life.
The principal health hazards for a dairy cow are mastitis (inflammation of the udder), milk fever (due to a sudden drop in blood calcium), ‘staggers’ (due to a sudden drop in blood magnesium) and ‘bloat’ (distension of the rumen — first stomach — by). But all these conditions can be treated and cured if caught in time.
Dairy Cows – Age groups
Any large dairy farm will have its dairy stock divided into different age groups. The main milking herd can easily be recognised as it is by far the biggest group and the cows graze with more purpose than, for example, the dry cows. The milking cow has a large and full-looking udder, while the udders of the dry cows appear shrunken by comparison.
When cows come to the end of their useful life, they are sent to be slaughtered for their beef value. In order to replace them, dairy farmers keep a group of young cows who have not yet calved (heifers). These often share the same field as the more mature dry cows. Most heifers are bred to produce their first calf by the end of their second year of life.
The yearling group of heifers is comparable with the carefree teenager in human terms. They are over the ‘baby’ stage and not yet into the breeding cycle. Physically, they look half-grown.
The bull calves are recognisable by the tuft of hair located under the belly, about mid-way between the front and back legs. On some dairy farms with Friesian herds, the bull calves are kept for rearing as beef, but it is more normal for them to be sold to a beef farmer. Bull calves of other breeds are sent for slaughter within a week or two of birth and used in pet foods.
Whether it is done in spring or autumn, calving is a busy time for the herdsman. In mild weather, it can take place in a small sheltered field, provided there are no ditches or other hazards. At other times, farmers prefer to use covered loose boxes. The cow about to calve is normally led into her loose box two or three days before the expected date.
About a day before calving, the ligaments on the sides of the tailhead loosen and the vulva becomes enlarged and flabby. The cow can be seen with her tail standing proud of her backside and she will be gently paddling on her feet.
At the time of calving, the water bladder appears first and then, in a normal birth, the forefeet with the muzzle of the calf resting on them. Occasionally assistance may be required. In this sort of case, calving ropes are attached to the forelegs of the calf and then pulled in rhythm with the contractions of the cow.
As the calf is delivered it may be necessary for the herdsman to remove any mucus from its nose and mouth to ensure easy breathing. The mother will invariably turn and lick her offspring with great rasping strokes. The effect is to stimulate breathing and increase blood circulation. Within minutes the calf raises its head and makes its first attempt to stand.
A calf’s chance of survival is greatly reduced unless it is suckled by its mother within the first six hours of life. This first milk is called colostrum and is a mixture of true milk and certain constituents of blood plasma — including vital antibodies — which have been concentrated in the udder before calving. Armed with these antibodies, the calf is in a stronger position to face the infections it will meet in the outside world.