As herds increase and more and more farmers are trying to get 90% of herds calved down within 6 weeks many calves are been born on farms within a shorter period of time but farmers should not use this as an excuse for poor calf rearing practices. As was covered by Alan Kelly in our dairy conference in 2018, early life nutrition and management of calves is key to maximising profitability especially in heifer calves that hopefully one day will form part of future herds. Attention to detail proves vital in ensuring calf rearing is a success. Detailed below are a number of areas which are fundamental in successful calf rearing.
Hygiene plays a significant role in calf health even before it is born. Not only is good hygiene important for the calf but is also very important for the cow. Around calving both the cow and calf can have poor immunity and are more susceptible to picking up disease from their environment. Cows can transmit pathogens in their faeces, urine, birth fluids, after birth and colostrum which can survive for days. Survival of these pathogens is increased by the presence of organic matter such as dirty bedding. This is why it is very important to:
• Have calving facilities cleaned out and disinfected before the calving season starts.
• Be aware of the different types of disinfectants available as there are different products designed to kill different pathogens.
• During the calving season calving boxes should be cleaned out and disinfected regularly to avoid disease build up.
• Calving equipment such as jacks, ropes, buckets etc should also be cleaned and disinfected between each calving to avoid build up of disease.
• Try to avoid using clean calving areas for abortions/premature or sick animals.
• Afterbirths should be disposed of through a knackery and stored in sealed containers if waiting collection.
In order to ensure a healthy calf you must have a healthy cow. The pre-calving period is an important time to set the herd up for calving and early lactation, which will also lead to better performance at breeding.
• Dry cows should be fed pre-calving minerals from 6 - 8 weeks before calving to help prevent milk fever, retained cleanings and other metabolic disorders. It will also help ensure the calf is healthy gets up quick with a good appetite.
• It is very important to ensure your cows calf down in a BCS of 3.25. The cows BCS should be monitored throughout the dry period and cows should be fed accordingly.
When a calf is born it literally has no immune system as no antibodies are passed from the cow to the calf during pregnancy. This is why getting good quality colostrum into the calf as soon as possible is so important. Colostrum is rich in antibodies that provide protection from disease in young calves until the immune system of the calf becomes functional.
• Aim to get between 2 and 3 litres into the calf within the first two hours as the efficiency of antibodies being absorbed declines rapidly from birth onwards.
• Quality of colostrum may vary between herds and even between cows. This is why it is advisable that farmers test the quality of their colostrum using a refractometer.
• If testing farmers should target colostrum with an IgG content > 50 g/l and a TBC < 100 cfu/ml.
• If the farmer receives excess good quality colostrum it may be frozen and used at a later stage.
• When reusing colostrum from the freezer it should be thawed out in a fridge overnight and then reheated to 39°C.
• Do not use a microwave when reheating colostrum.
To ensure calves stay healthy and perform well calf housing must have;
• Calves up to 100kgs require an area of about 2-2.5 m2 . The more space a calf the better they will perform.
• Fresh air is very important for calf sheds as it sweeps out dust and ammonia.
• Fresh air almost acts like a disinfectant as viruses survive longer in stale air than in fresh air.
• Although air is important it should not come in the form of a draught. A draught is a flow of air of greater than 0.5m/second that gets in below the animals height. This is why calf shed should be sealed to at least 4 feet to prevent draughts occurring.
• Calf beds should be kept dry and clean as it decreases the survival and spread of bugs while also decreasing the temperature.
• Floors should have a good slope into a channel or a drainage pipe that is cleaned regularly to ensure good drainage.
• Feeding area should be kept clean and buckets should never be washed or emptied in calf pens.
• To reduce labour and ensure cleaning is carried out regularly the shed should be easily accessible with a loader.
• Calves perform best at 15-20° C but they are unable to insulate themselves from colder temperatures until their rumens are fully developed.
• In order to try and keep calves warm a good dry deep bed of straw should be provided.
• For younger weaker calves breathable calf jackets are a useful option to help boost performance until they are capable of generating enough of their own heat.
With more and more farmers now targeting calving at 22-24 months it is vitally important target weights are met. The target growth rate for a calf from birth to weaning should be for it to double its weight. This means for example a calf with a birth weight of 45kg should aim to be 90kg when weaning at the 8-10 week stage. In order to achieve this a growth rate of at least 0.8kg per day should be targeted.
• After the first feed calves should be fed up to 5 litres a day for the first week and 6 litres thereafter up until the week before weaning.
• In order to maximise a calves genetic potential and ensure effective rumen development solid feed and fresh clean drinking water should be introduced from day 3 or 4.
• It is vital to promote early intake of starter feed to physically and microbally develop the rumen of the calf so the animal can digest fibre as soon as possible.
• By promoting high levels of starter intake you’re increasing the amount of volatile fatty acids which are result of rumen fermentation of carbohydrates.
• These VFA’s especially propionic and butyric acid are vital for developing the rumen papillae which is essential for nutrient absorption in the rumen going forward.
• A fresh high energy high protein calf starter should be fed with a target intake of 300g/head/day by week 3. Concentrates are far more important for the development of the rumen than roughages.
• Water should be made available from 3 days on as milk is not a substitute for this.
• Water is also critical for rumen development and good calf health.
• Weaning should be done based on concentrate intake as this correlates with rumen development.
• The calf must be eating at least 1kg of concentrates a day for 3-4 consecutive days before weaning can occur. This will ensure the calf is capable of dealing with the transition of being a pre ruminant to a ruminant.