Husbandry and Management Principles of a Dairy Herd

Husbandry and Management Principles of a Dairy Herd

• Typical Dairy Cow
  Weighs 40kg at birth
  Reaches puberty at 1 year old when she is 250kg
  Oestrus Cycle (reproductive cycle) is 21 days and oestrus (heat) lasts for 18 hours
  Gestation period (length of pregnancy) is 283 days


• Planning Production
  Milk production in Ireland is a low cost system based on producing milk from summer grass.
  Farmers must plan breeding so that cows calve in spring and are producing most of their milk when they are grazing grass.
  Farmers must also balance the amount of grass that is cut as silage because if too much is cut then cows will have to be fed concentrates in the summer and if too little is cut they will have to be fed concentrates in the winter.


• Managing the Dairy Cow
  Calving
  oMismanagement of the cow at calving can cause death, injury, loss of milk production or problems with cow fertility.
  oCows should be isolated, in a disinfected calving pen, 1-2 days before calving. Keep accurate breeding records.
  oAn experienced person should inspect the cow regularly.
  oCall the vet if there are any difficulties


• Calving
  Once the calf is born:
  Clear away all mucus from its airways.
  Allow the cow to lick the calf.
  Dip the calf’s navel in iodine.
  Ensure the calf receives 2 to 3 litres of colostrum.
  Tag the calf


• Calf Rearing
  Calves can be reared naturally by suckling the cow or artificially away from the cow.
  All dairy calves are reared artificially (bucket reared).
  The calves that are reared from the dairy herd may be used as replacements for older cows or they may end up being used for beef production.


• Calf Rearing
  Depending on the breed of bull used the calf will be different weight when born:
  Aberdeen Angus -35-40kg
  Friesian/Holstein - 40-45kg
  Continentals - 45-50kg


• Colostrum
  The importance of colostrum to the new born animal cannot be overstated.
  Colostrum is the first milk produced by the cow and is commonly called beastings.
  It is unlike normal milk because it has very high levels of vitamins, minerals, fat and most importantly antibodies.
  The new born animal must receive 10% of its bodyweight in colostrum within 12-24 hours after birth.
  There are two reasons to get it in quickly:
  (i) the level of antibodies is highest in colostrum directly after giving birth
  (ii) the calves ability to absorb those antibodies into its bloodstream decreases rapidly in the first day of its life.


• Functions of Colostrum
  1.A calf is born with no immune system and the antibodies in the colostrum prevent it from getting disease while it develops its own immune system.
  2.The increased fat level in colostrum acts as a laxative to clear out the calves digestive system.
  3.The increased fat, protein, vitamins and minerals in colostrum stimulate the calf to start growing.
  It has been shown that inadequate intake of colostrum can affect the calf's growth and development for at least three months. Most deaths in calves are linked to inadequate intake of colostrum early in life.


• Feeding the Calf
  The calf will be fed colostrum for 3-4 days.
  After this the calf will be fed milk or milk replacer(usually 2 litres twice a day).
  This is because the calf’s digestive system cannot digest cellulose based foods as its rumen is not developed.
  To help develop the rumen of the calf we offer it hay and concentrates from 1 week of age.
  At first it will eat very little but as the rumen develops it will eat more and more.
  When the calf is eating 500g of concentrates per day we can wean it off milk/milk replacer. This is usually happens at about 8 weeks of age.


• The Calf on Grass
  As soon as the weather is mild enough the calf is let out to grass.
  The calf should continue to be fed concentrates for three weeks to allow it to get used to its new diet.
  Calves are very selective grazers and should be given the pick of the best grass. For this reason we graze them as leaders in the leader follower system of grazing.
  This also helps to control stomach and lung worms as the calves have no resistance to these.
  When grass becomes scarce later in the year concentrates are again fed. By the first of November the calf should weigh 200kg.


• Managing the Dairy Cow
  Early Lactation
  For the first 3-4 days the cow produces colostrum which is fed to the calf.
  The sudden onset of milk production causes the cow to “milk off her back”
  When she enters the herd the cow should be fed very well (silage and concentrates) to ensure she reaches her lactation peak.
  Peak Yield X 200 = Total Lactation Yield
  First time heifers fed extra because they are not fully grown and we do not know their potential yield.
  Turn out to grass depends on weather, geographical location and fertiliser use.
  Continue to feed concentrates if grass is scarce and to very high yielding cows. (Watch for grass tetany)


• Breeding
  Cows fed well after calving to ensure they are in good condition when they are serviced again.
  Cows come into heat 3 – 8 weeks after calving.
  To ensure the calving interval (time between calvings) is kept at 12 months cows must be serviced not later than ten weeks after calving.
  Cows are observed regularly for signs of oestrus (heat) when they mount each other. Tail painting helps the farmer with heat detection.
  Dairy cows should be inseminated with top quality AI bulls.
  Keep accurate records.


• Reproductive Efficiency
  This means the number of calves weaned per 100 cows served.
  To ensure good reproductive efficiency we:
  Feed cows well before mating
  Have good heat detection
  Have good care of the cow at calving time
  Cull older cows


• Tail Painting
  The use of emulsion paint is common in Irish dairy herds.
  Cows are painted with a bright colour (every 7 to 8 days) to help the farmer to detect the cow in heat.
  The paint will be broken or rubbed off by other rising cows or servicing bull.
  The colour is then changed, so that repeats of heats can again be detected and the repeat service once again recorded.
  This practice reduces the need for round the clock observation and the detection of cows who may have short (2 hours) standing heat periods. Tail paint when dry.


• Advantages of Artificial Insemination
  Longer period for inserting the sperm into the vagina so success at fertilisation is greater.
  Better use of semen produced by the bull as it can be diluted to service a number of cows.
  The life of the bulls is prolonged by refrigeration of the semen.
  The need to feed a bull is not required.
  The best beef and dairy bulls are available to every farmer.
  Less risk of disease transfer.


• Managing the Dairy Cow
  Mid and Late Lactation
  Grazing highly digestible young leafy ryegrass in a rotational system e.g. paddock grazing.
  oNear the end of lactation cows milk yield reduces and they are dried off two months before calving.
  Drying cows off for this period gives the cow a chance to build up energy for calving, clear up any infection in her udder with the use of antibiotics and at this point we steam her up.
  Steaming up is feeding the cow on an increasing plane of nutrition coming up to calving. Start with 2kg of concentrates per day 10 weeks from calving building up to 6kg at calving.
  It is done because during this period the size of the calf in the womb is increasing rapidly.


• Replacement Heifers
  Cows need to be replaced at a rate 20% every year.
  Farmers replace cows for a number of reasons:
  Poor milk yield due to age
  Disease, especially mastitis
  Injuries, especially to feet
  Fertility problems
  Grading Up – this refers to replacing older poor yielding cows with the daughters of higher yielding cows thus increasing overall milk yield.


• Rearing Replacement Heifers
  A replacement heifer should be bred from a high yielding cow and an AI bull.
  Born in February and should weigh 72.5kg by April.
  Grazes on top quality perennial ryegrass for the summer and weighs 200kg by November.
  For the first winter is fed on silage and some concentrates to ensure she meets her next target weight of 300kg on the first of May.
  It is essential that she meets this target weight before she is put in calf. If not she will be too small when calving and never reach her full potential milk yield.

 

• She is usually put in calf to an easy calving beef bull such as Aberdeen Angus or Hereford. This is to ensure she does not have a difficult calving that might affect future production.
  By the end of her second summer she should weigh 450kg.
  She is fed good quality silage and steamed up on concentrates in her second winter. This ensures she weighs 500-525kg at calving.
  She is not fully grown at this stage and must be fed extremely well in early lactation to account for maintenance, milk production and growth.


• Economic Breeding Index
  EBI: A single figure profit index given in euros of profit per lactation for the animal’s progeny compared to an average dairy cow.
  Developed by Teagasc and the Irish Cattle Breeding Federation.
  Helps farmers to identify dam and sire lines that would be most profitable in their dairy herd.


• Diseases of Cows
  Grass Tetany (Hypomagnesaemia)
  occurs in the first few weeks of lush green growth. It is due to a low level of magnesium in the blood, resulting from a low level in the grass.
  Symptoms usually include excitement, twitching of muscles, staggering and death.
  To prevent include calcined magnesite in the diet of the cow
  Milk Fever (Hypocalcaemia)
  Occurs immediately after calving and is caused by low levels of calcium due to sudden onset of lactation.
  Symptoms include nervousness, inability to stand and death.


• Brucellosis
  It is caused by the bacteria Brucella abortus and can be transferred from animal to animal
  Symptoms include the foetus being aborted between the 5th and 8th month of pregnancy. Cow loses weight before calving. A discharge is given off and should be reported to the vet as soon as possible.


• Mastitis
  It is the inflammation of the udder and is caused by bacteria. It affects milking or dry cows.
  Symptoms in dairy cows include watery milk, clots or strings, blood and sometimes pus.
  Symptoms in dry cows include swelling of hocks, lameness and discharge.
  Prevention includes hygiene at milking, the practice of stripping the cows and teat dipping.
  As it occurs in older cows the younger ones should be milked first.
  Cows known to have mastitis should be milked last on their own. Treated with antibiotics and cows with a recurring problem should be culled.


• Diseases of Calves
  Scour (Diarrhoea)
  Two Types:
  1.Nutritional Scour
  –Calf ingests too much milk in one feed
  –A “milk ball” is formed in the stomach causing digestive upset
  –To treat take the calf off milk and put on electrolytes (sugars and salts) for 24 hours
  –To prevent feed at regular intervals and don't overfeed
  2.Bacterial Scour
  –Caused by poor hygiene and is highly contagious
  –Isolate calf immediately and call vet
  –Vet will prescribe antibiotics and put calf on electrolytes
  –To prevent ensure good hygiene


• Virus Pneumonia
  Highly infectious and usually there is secondary infection by bacteria also
  Spread of infection is encouraged by poor ventilation
  Coughing, fever and death
  To treat call the vet
  To prevent have good ventilation and check calves regularly for signs of disease


• Naval Ill (Joint Ill)
  Caused by bacteria entering the calves’ unhealed navel
  Results from bad hygiene at calving time
  Swollen naval, joints and can lead to blood poisoning and death
  Treat using antibiotics
  To prevent treat the calves’ naval with iodine when it is born