Dairy herd management involves four main aspects:

1. The management of the dairy cow
2. The management of the calf / replacement heifer
3. Managing disease & health (including nutritional health)
4. Managing risks and safety.

Management of the Dairy Cow

The diagram above represents the stages of a typical spring calving dairy cow. Let's look at the main stages:

Stage 1: Feb - April

• Calving season begins around mid February, when the cows are usually houses indoors (more on this later).
• Cows are being fed a mixture of good quality silages (high DMD) and concentrates.
• The cows are not being milked at this stage ... they are dried off from early December.
• The sale of calves would account for nearly 30% of the farmer’s annual income so mistakes can be costly.
• The most important consideration is the care of the cow before and after calving and the care of the calf at birth and the first 24 hours of it’s life.
• Every year 6% of all calves die at birth and another 3% in the first week. Most of these are avoidable and are caused by silly mistakes.
• Mistreatment of the calf can also lead to injury of the cow, lower yields or even death.

We will discuss the management of the calves later.

• After calving, the cow produces special milk called colostrum.
• This milk is not accepted in the creamery as it contains types of antibodies so the cow should not be returned to the herd straight away.
• The cow will continue to lactate until she becomes pregnant again (or for 2 years if suckled) but the farmer will aim for a period of 10 months.
• During this 10 month period the daily milk yield will vary considerable.
• The LACTATION CURVE shows the typical trend during the cows lactating period. Click here to review lactation.

Stage 2 - April

• In April, two major events occur on a dairy farm.
• No 1 - The cows will be moved from their winter housing to outdoor grazing.
• No 2 - The cows will return to heat (oestrous) and mating season begins.

• Cows can be reared naturally by suckling the cow or artificially away from the mother.
• In dairy farming all rearing is done artificially as the farmer could not allow for the loss of milk.
• Calves being reared may be reared for two main reasons:
  
  • 1. Heifer calves being reared as replacements for the dairy herd.
  • 2. Heifer or bull calves being reared as weanlings or fattened up for beef production.
• Whatever the final purpose of the calf, the principles of rearing are the same.
• Calves should be housed in clean, well ventilated, draft free houses. Poor ventilation can lead to pneumonia. 

Managing the Calf / Replacement Heifer

Stage 1 - Feeding Colostrum

• There are many differences between colostrum and normal milk and they are summarised below:
• Colostrum is a more concentrated material and contains large amounts of highly digestible materials.
• Most importantly however is the higher levels of protein in colostrum, much of which is made up with immunoglobulins.
• These substances are known as antibodies, which give the calf protection against certain diseases.
• Unlike the human baby, the calf is not born with these antibodies in their system, so it is vitally important that the young calf get colostrum as quickly as possible.
• The calf can absorb antibodies more quickly in the first 12 hours of its life, and the calf should ideally consumed 2 – 3kg of colostrum in this period.
• It should be hand fed if the calf is too weak to suckle the mother.
• Colostrum should be fed to the calf for as long as it is available, usually 3 – 4 days.
• Excess colostrum can be used to feed other calves or frozen.
• It is exceptionally important for the calf to get colostrum in the first 12 hours of its life.
• Research has shown that the majority of deaths, illnesses and failure to grow properly in the first three months, are down to the improper intake of colostrum.
• If the cow dies during birth, colostrum from another cow may be used.

Stage 2 - Feeding Milk Replacer

• Milk is the food ideally suited to the digestive system of the calf.
• It is however app. 160% the cost of milk replacer and 300% the cost of concentrate ration.
• The calf however cannot digest concentrate ration at an early age, as its rumen (stomach) has not developed fully.
• The normal procedure, therefore, is to feed the calf using the following sequence of feeds:
  • 1. Colostrum
  • 2. Milk
  • 3. Milk Replacer
  • 4. Concentrate ration.
• The quicker the calf can be weaned onto ration the better, as this means less cost.
• However, this may not happen until the calf is 5 - 6 weeks old.
• The digestive system of the calf is very sensitive and is easily upset.
• It is only in recent years has the use of milk replacer been perfected by most farmers in the rearing of calves.
• Milk replacer is prepared by mixing 125g milk replacer powder to every 1 litre of water.
• It must be fed gradually as the calf may react to it. This is usually done over a period of 4 –5 days.
• Bucket fed calves are given 2 litres if milk replacer twice daily at body temperature.
• They may also be fed using an automatic feeder, where the calf can have as much as they wish.
• However this is only used with large amounts of calves, as the cost is much higher.

Stage 3 - Weaning on to Hay & Concentrates

• Hay, concentrates and water should be available to calves as soon as they stop drinking Colostrum.
• At first the level of hay and concentrates they consume will be very low, but this will increase as the calf gets older.
• Both foods not only provide essential materials for the calf’s growth, but also contain microorganisms, which help develop the calf’s rumen flora and enable it digest fibrous material.
• This is known as building the Scratch Factor.
• By the time the calf is four weeks old, he / she should be eating 300-400 g of concentrates daily.
• When the calf is weaned from milk replacer, he / she should be eating 500 g a day.
• At this time the calf is allowed onto grass, but is still fed concentrates, hay and water.

Stage 4 - The Calf on Grass 

• Calves should be allowed onto grass until the weather is warm.
• The change from warm housing too cold outdoor conditions can cause a shock and can disturb the calf’s growth.
• Meals should be fed for 2 – 3 weeks after being put onto grass, to help the calf adjust to the new diet.
• Calves are selective grazers, and should always be kept on fresh, palatable grass and certainly should not be left graze pastures bare.
• They should graze under a leader – follower system.
• They should always graze in advance of older cows.
• This also inhibits the spread of stomach and lungworms.
• When grass is scarce at the end of the summer, concentrates should be fed.
• When calves are housed for the winter, they should weigh 200kg.
• They are now known as weanlings.

Replacement Heifers

• Cows need to be replaced in the herd at the arte of 20% per year.
• The main reasons for replacing are:
  
  • 1. Poor milk yield with age
  • 2. Infertile
  • 3. Disease
  • 4. Injury to udders
  • 5. “Grading up” -
• Grading up means replacing lower yield cows with better calves which should give higher yields. It can also mean improving the genetic merit of the herd.
• The rearing of replacement heifer calves is the same as previous.
• Replacement heifers should have the following characteristics:
  • Be purebred dairy breed (e.g. Holstein Friesian) 
  • Good teeth, feet and well formed udder.
  • Be free from disease.
  • Come from mothers of high milk quality or yield.
  • Come from mothers with good fertility, mothering ability and temperament.
  • Come from a bull with a high Economic Breeding Index (EBI).
• Over winter, replacement heifers are fed high quality silage supplemented with concentrates.
• The farmer will monitor the replacement heifer's weight to ensure she reaches at least 280kg by mid February (one year old - now called a yearling) and 330kg by the time of mating (mid April), with a condition score of 3.25.
• Yearlings are grass fed on a rotational basis (perhaps within the leader-follower system).

Managing Risks & Dairy Farm Safety

• All farms can be dangerous places and working with large farm animals regularly, as in a dairy farm, mean that there are always dangers on a dairy farm. 
• The following chart outlines some of the risks associated with working with dairy animals and how these risks can be managed.

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