Top tips for calf rearing

Colostrum management (the 3 Q’s)

QUANTITY    

Calves should receive 15% of their birth bodyweight of colostrum in the first 12 hours of life, over the first 2 feeds. 

For the average kiwi-cross calf this would be 5 litres of colostrum split over the first 2 feeds (e.g. 3L tubed at the first feed and then 2L given at the second feed). At least the first feed should be tubed, so that you ensure the calf receives the total amount, and depending on the individual farm set-up, the second feed may be tubed or fed to the calf via a teat. 

QUALITY 

Not all colostrum is made equal; many factors can affect colostrum quality including cow genetics, dry cow nutrition and dry period length, first milking volume and immune status of the cow. With so many variables to consider, the only real way of knowing if a colostrum is any good is by testing it! The easiest and most effective way to do this is with a BRIX refractometer.  

A Brix refractometer measures how much protein (antibodies, also known as IgG) is in a sample of fluid by how much it bends or distorts light. Whilst it may sound intimidating at first, this is an easy procedure that takes under a minute to perform and has no ongoing costs or delicate parts.  

A reading of >22% can be considered ‘Gold colostrum’, while readings of <22% should be considered second tier. The level of IgG within a cow's colostrum reduces significantly after calving - about 3.5% per hour! So, getting that first milking from freshly calved cows ASAP will help to ensure more of your colostrum is hitting the 22% mark.  

However, getting the colostrum from the cow is only half of the battle; colostrum degrades quickly when it is removed from the udder, so adequate preservation is paramount.   

Rules for preserving colostrum: 

When it comes to colostrum, cleanliness is above godliness. Contamination significantly degrades colostrum quality as the antibodies are used up on the contaminant, before they can be absorbed by the calf to develop the calf’s immunity. Contamination can come from dirty udders, non-sterile cups and collection buckets, and of course dirty storage buckets. Make sure all pieces of the system are thoroughly clean when collecting colostrum and ensure storage buckets have lids.  

At room temperature, bacterial populations can double every 20-30 minutes so even small amounts of contamination can turn gold colostrum into less than adequate transition milk within a few hours. Refrigerating colostrum will extend the shelf life to 48 hours (about 2 days). Whereas adding potassium sorbate and refrigerating samples will allow colostrum to last for up to 7 days.  

Only mix ‘like with like’ colostrum i.e. Gold colostrum should only be mixed with other Gold colostrum collected on the same day. Mixing Gold colostrum and second-tier colostrum only creates more second-tier colostrum. 

Frozen colostrum will store almost indefinitely but needs to be thawed gently with warm water. Heating too quickly will cook the valuable antibodies and render them useless. 

All colostrum should be warmed to >20 degrees C (but no higher than 38 degrees C) prior to feeding. Feeding warm colostrum (and then milk) optimises gut mobility, increases gastric juices and increases protein digestibility.  

QUICKLY 

Calves are born with no antibodies (hugely important molecule required for immunity), and they rely entirely on colostrum (and the IgG antibodies in it) for their immunity in the first few weeks of life. To make things tricky, as can be seen in the graph below, their ability to absorb these antibodies decreases dramatically over the first 24 hours of life. The most significant (and eye-opening) point being that by 12 hours of age only 5% of antibodies being fed are absorbed by the calf!  

Therefore, all calves should receive their required volume of colostrum (15% birth bodyweight over 2 feeds) within the first 12 hours of life.  

sQUEAKY CLEAN  

Strict hygiene practices should be implemented when handling fresh cows and colostrum. If the udder is filthy, then the teats should be gently cleaned and allowed to drip dry before collection. A pre-teat spray using an iodine-based product (1:4) is also strongly recommended. Squeaky clean collection buckets and storage buckets should be used, and storage buckets should also have a sturdy lid to prevent contamination.  

Wash hands and wear gloves whenever handling colostrum (collecting, storing or feeding) to avoid contamination.  

All equipment should be cleaned between animals (a warm, soapy water and bleach mixture is a cost-effective and suitable option). Ensure that after being cleaned all equipment is flushed with warm water and allowed to air dry (if time allows).  

QUANTIFY  

This is best done by testing the passive transfer of calves to determine their level of antibodies. This gives an indication of how well colostrum is being managed and fed to the newborn calves, and how good their immunity is as a result. 

This is done by collecting blood samples from 12 calves within the first 7 days of life. Ideally, at least 2 samples should be taken throughout the season – one at the beginning of the season and one mid-season.  

           * This can be done by our wonderful tech team at the time of disbudding! * 

Life in the calf shed 

An ‘all-in and all-out' system is the preferred method of housing calves. Calves should be housed within similar age groups; ideally new calves will be housed together and then remain together within that group. This prevents exposing young (and more vulnerable calves) to the older calves in the shed, who may expose them to infectious diseases. If groups of calves do need to move between pens, then it’s important to clean and disinfect these pens between groups of calves/prior to a new group of calves entering a pen.  

The other management factors to consider when housing your calves include:  

FEEDING ROUTINE

Recent research has shown that calves fed twice per day for the first 2-4 weeks of life develop and grow to a level far superior to those animals fed only once a day. One feed per day alone in the early weeks of life cannot provide the calf with enough energy to grow, maintain an adequate immune response and have the energy to express normal behaviours (such as play). Therefore, we recommend twice per day feeds for the first 3-4 weeks of life. Ad lib access to milk feeds is also an option that can be considered for newborn calves, however the feeding set up and hygiene practices will need to be modified to accommodate this.  

A good quality calf meal, with a crude protein level of 20%, should also be provided ad lib to all calves to aid in rumen development. This should be a sweet-smelling meal mix (ideally with molasses included to make it palatable) and a fresh amount should be provided daily.  

From at least 4 weeks of age (earlier is also great) a source of forage should also be provided to calves – this could be grass, hay, lucerne or straw. Ideally kept in a raised rack to prevent calves from trampling and toileting on it. Again, this should be changed regularly to keep the source fresh and appealing.  

All calves should also always have access to a fresh, clean water source that is within their reach. Ensure that the trough is cleaned at least weekly, and any leaks are promptly repaired to prevent water pooling in the pen.  

REMEMBER: If you are using calf milk replacer on farm, this contains coccidiostats which are toxic to dogs. Make sure it is stored correctly - in a cool and dry environment, out of reach of your furry companions!

HYGIENE

Calf pens should be thoroughly emptied and disinfected between groups of calves (and of course, at the end of each season). They should also be sprayed with a disinfectant product (such as Virkon) twice a week.  

As well as maintaining a high level of hygiene within the walls of the calf shed itself, it is important to ensure that all equipment used (e.g. feeder, feeding tube, buckets etc.) are cleaned after each use and remain in a very clean condition. A warm soapy water and dilute bleach mix is a great cost-effective option for regularly cleaning equipment. Be sure to flush them all again with warm water and (if time allows) allow them to air dry in between uses.  

Teats should be replaced each season. And any materials that become damaged throughout the season (e.g. chewed teats or a chewed calf tube) should be replaced promptly. This will prevent the likelihood of injury occurring as well as bacteria establishing on the surfaces of these materials and being passed onto the calves potentially resulting in an infection.   

CALF HOUSING

Each calf should receive 1.5-2.5m2 within the calf shed. Pen orientation is key to ensure that an adequate level of sunlight is received each day, and ventilation is of huge importance for reducing the incidence of respiratory disease. However, it is a balancing act, as draughts within calf pens can also lower the air temperature and expose young animals to the elements, resulting in reduced growth rates.  

Ideally, the partitions between individual calf pens will be solid (i.e. no nose-to-nose contact between pens); this is another strategy for minimising the transfer of disease between pens if an outbreak were to occur.  

A comfortable and dry bedding, that drains freely and keeps calves warm and dry should also be used in each of the pens. We’re sure it comes as no surprise, but recent research has shown that calves reared on stones spend less time lying down and playing within their environment. Wood chips and straw are great options!  

Enrichment is also important for calves. Providing opportunities to explore and play can alleviate boredom and prevent calves from nibbling on their friends and sucking navels. Make sure that these are also regularly cleaned and disinfected (ideally once or twice per week).  

Some ideas include: road cones, swiss-ball or football, rope attached to the wall within the pen.  

Sick Calves

A dedicated sick calf pen is essential for all calf-rearing facilities. Any calf showing signs of illness should be promptly separated into this pen. The pen itself should be separated from the main pens (at least with solid partitions) and meet the same standards, in terms of bedding, access to feed and water etc., as the remainder of the calf housing system. Strict hygiene protocols should be implemented when handling calves separated in these pens;  

• Handled last  

• Fed last  

• Separate equipment for this pen 

• Wear gloves 

• Separate set of boots and wet weathers for this pen only  

• Footbath (this needs to be changed daily)  

A thorough disinfectant of the pen should be performed between each animal (or group of animals) kept within it. Ensure that all staff are aware of the protocols in place for caring for sick calves; this will prevent mishaps and disease spread.    

Electrolytes are of utmost importance when it comes to sick calf care, particularly during a scours outbreak. Ensure you have a sufficient supply of electrolytes available on hand for the season. (Please note: we don’t recommend using home-made electrolytes/home-brews as the concentration and ratio of electrolytes is often unbalanced and does not aid in rehydration). It is important that scouring calves receive both electrolytes and milk feeds, and that the total volume of fluids they are receiving per day is higher than that of a healthy animal (to allow for fluid loss and dehydration). Below is the treatment protocol that we recommend when calves require electrolytes, as well as the volume that should be given for each feed:  

Faecal sample collection 

When a calf is scouring, a fresh poo sample is of great importance and helps to determine what pathogen is causing the diarrhoea (and if one is even present at all). When collecting samples you will need: 

• Clean gloves  

• Clean sample pottle  

• Pen/Vivid to label with calf ID  

If you are struggling to get a sample from a specific calf, then gently rubbing below the anus with the back of a gloved finger can often stimulate the anus to relax. Be sure to be ready with your sample pottle – we've all seen how quickly poorly formed poos can exit a calf’s bottom! Label the pottle with the calf’s ID as soon as possible. Refrigerate the sample(s) between the time of collection and getting the sample to the clinic.  

Depending on the age of the calf and the clinical presentation will determine how long the turn-around-time is for samples (those that are suspected to be bacterial and require to be cultured at the lab may take 3-4 days) whereas there are ‘snap tests’ available for most of the viral causes of diarrhoea which only take a short time to run in-house.    

Vaccination 

Vaccinating your heifers and cows with Biobos® 3-12 weeks pre-calving boosts the antibodies in their colostrum and transition milk against three of the most common scour-causing pathogens:  

• Rotavirus  

• Coronavirus (not the Covid-19 kind!)  

• E. coli  

The pathogens mentioned above are present within the environment on most farms in NZ, so calves need all the protection and help they can get to prevent them from getting sick if they do encounter one of these. Vaccinating cows, and the transfer of this protection to calves via colostrum/milk, will reduce the risk of your calves getting scours & reduce the severity of any cases that do arise.  

It is very important, however, to remember that vaccinating the dam (and having the antibodies present within the colostrum) is only part of the equation. Ensuring calves receive the adequate volume of quality colostrum, that has been collected and stored correctly, within the first 12 hours of life is of upmost importance in preventing the occurrence of diarrhoea in the calf shed!  

PLEASE CONTACT US for more information regarding when your calves may require electrolytes and our recommended volumes.