Healthy calves, healthy profit webinar Q&A

On 9 September 2020, John and Anna Booth from Rhual Dairy, together with Dr Robert Hyde from the University of Nottingham, took part in a webinar on improving calf health. Here you can find a full list of the questions, along with the answers, taken from the webinar.

Do the deaths quoted in the research slides include euthanised calves and dairy bull calves?

The deaths in the graph shown were for on-farm deaths only, so would only include animals that were registered and subsequently died on farm. They would not include animals dying (for any reason) prior to registration.

What is the recommendation for feeding and bedding?

Quite a broad topic, but in general feeding 6-8 litres per day and providing plenty of fresh, dry bedding to the point where the calves’ legs can’t be seen when lying down is a good starting point. Calves being fed lower volumes of milk are likely to have poorer daily liveweight gain performance and also suffer from hunger. Providing lots of clean dry bedding (even if only for some of the pen) allows calves to nestle down and stay much warmer, as well as limiting the chance of exposure to pathogens from dirty bedding.

Where is the best place to put a temperature gauge in a calf shed (height/calf level)?

Ideally at calf lying height close to where they spend most of their time, but out of reach so they can’t chew the monitor. Generally speaking, at about 1.5m at the back of the pen gives a reasonable idea of shed temperature while making sure the temperature monitors aren’t destroyed by inquisitive calves.

Did you look at other bedding types as part of the project appose to just straw?

There were no farms using bedding materials other than straw on this trial so it was not something we could compare.

What age should you remove a calf jacket?

Calves are at most risk of being too cold in the first 3-4 weeks of life, so that’s where we should prioritise efforts to keep them warm. If using jackets, make sure they are kept clean and dry between calves.

When using a thermometer, do you use minimum/maximum or average temperature especially when there is change in temp day/night?

All are useful measurements to look at. The minimum overnight temperature is often colder than we think, for young calves if they are below 12-15C they are likely to be too cold and will be burning energy just to stay warm.

For New Zealand grazing system, what is the best calf housing?

It can be challenging in pasture-based/seasonal calving systems to cope with a large number of calves at one time. Really there is no ‘best’ housing, but providing the calves with good shelter from the elements, ventilation (but not a draught at calf level) and the ability to regularly clean out calf pens is a good starting point. Much more importantly is the person managing the calves, and plenty of clean dry bedding alongside a highly attentive stockperson can result in excellent calf performance even when the calf housing is not optimal.

Can you test for ammonia easily? The more straw we use in the hutches, we get ammonia build up. How could a large hutch be ventilated or is their different bedding that would be better used?

There are a number of ammonia monitors available if you’d like to monitor directly. If ammonia levels are increasing, it could be worth increasing cleaning out frequency to remove dirty bedding. Ventilation of large hutches will change depending on the day, there are often vents that can be opened or closed depending on the weather, and mechanical ventilation could also be considered if vents do not provide enough ventilation

Will pasteurising colostrum damage the quality content?

While some studies have suggested pasteurisation at higher temperatures can damage the immunoglobulins in colostrum that provide immunity to the calf, pasteurising colostrum at lower temperatures (60C for 60minutres) with a commercial pasteuriser is unlikely to significantly damage the immunoglobulins. It is likely to significantly reduce bacterial levels which means the calf is at lower risk of disease, and stands a better chance of absorbing the immunity it needs (Godden et al., 2012). However, pasteurisers are relatively expensive so it is worth making sure the investment is right for your farm.

Do you need to wash all equipment in hypochlorite or peracetic acid, or just the buckets I carry the colostrum in?

Every piece of equipment that colostrum comes into contact with is a potential source of bacteria. Colostrum from the cows’ teat has extremely low bacterial levels, but a high number of bacteria can come from the equipment we use, even if it looks clean to us. Our colostrum bacteriology research would suggest it is worth cleaning all collection and feeding equipment with hot water rather than cold water, and either hypochlorite or peracetic acid rather than parlour wash or water to ensure bacterial levels are as low as possible.

How long can you freeze colostrum for?

Up to 1 year, providing it has been frozen within 1 hour after collection and is thawed correctly (Godden et al., 2019)

What is a good replacement if you don’t have good quality colostrum?

If you do not have good-quality colostrum, or are unable to build up a bank of high-quality frozen colostrum, then colostrum replacer is a viable alternative and is likely to provide relatively similar levels of immunity to calves (Lago et al., 2018)

Do you test every cow’s colostrum?

It is only worth testing if it is going to make a difference to your decision on whether to feed. With a refractometer it is extremely quick to test colostrum quality, meaning poor-quality colostrum can be discarded in favour of high-quality stored colostrum or colostrum replacer.

Does freezing colostrum affect quality?

Freezing is not likely to affect colostrum quality. Even multiple freeze-thaw cycles have been shown to have minimal effect on colostrum quality (Morrill et al., 2015)

Can you increase the colostrum quality by what you feed a cow?

It can be challenging to affect colostrum quality through adult cow dietary changes. It is much easier to focus on the quantity and speed of colostrum feeding, and ensuring your colostrum hygiene protocol is optimal by cleaning all colostrum equipment with hot water and either hypochlorite or peracetic acid each time it is used.

What is the economic impact of bad colostrum management?

Often higher than we think. A study in 2016 found the cost of failing to get good immunity transfer from colostrum to be around £55 for dairy calves, and £75 for beef calves (Raboisson et al., 2016). Failing to get immunity from colostrum means calves are 1.5x more likely to get scour, 1.8x more likely to get pneumonia, and 2x more likely to die, and investing time in improving colostrum management is often extremely worthwhile. 

How much doe 1cm equate to on a weigh tape?

This really depends on the weigh tape. Most weigh tapes have both cm and kg measurements.

What is the impact of scours on profit?

Often higher than we think. Costs of scour don’t just involve the cost of treatment, but also the affect on growth rates and mortality rates must also be factored in. A report on the economic impact of diseases in England found the cost of a scour outbreak for a suckler herd to equate to around £60/animal (ADAS, 2013).

Does feeding more milk reduce dry food intake?

Increased milk feeding can reduce starter intake initially. However, overall increased milk feeding can improve growth rates, reduce the incidence of disease and calves also express higher levels of natural behaviours (Khan et al., 2011).

Would you feed a jersey calf 6 litres per day?

Variations between breeds certainly exist for milk intakes. Generally speaking, calves can be fed up to 20% of their body weight in milk volume (Khan et al., 2011). So, while initially a young Jersey calf might not drink 6 litres per day, it would not be an inappropriate volume to feed later in the pre-weaning period.

How soon can a calf manage to drink 8 litres per day?

Calves with their mother will drink large volumes of milk, spread out through many small feeds throughout the day. When feeding on automatic feeders, they can increase to 8 litres at a steady rate. However, on twice daily feeding, 4 litres per feed is a lot to take at one time for a very young calf. It is often worth slowly increasing milk feeding volume to 6-8 lires per day over a period of a few weeks when on twice daily feeding. 

If feeding 6/8 litres of milk per day, what rate of milk solids should be provided daily?

Milk replacer powder is often fed at a rate of 125-150g/litre. It is not often worth feeding higher concentrations than 150g/litre, but it is important to weigh this concentration out with scales to make sure the milk powder concentration is accurate. Measuring with a cup or jug for milk powder will often result in variable powder concentrations between feeds. 

What is the maximum feed size I can give if feeding twice daily?

This really depends on the breed and size of the calf. It would be unusual to go above 4 litres per feed in a twice daily feeding system. As calves have evolved to have lots of relatively small feeds throughout the day, there is some research evidence that even 4 litres per feed might have negative metabolic consequences to glucose metabolism and daily liveweight gain (Yunta et al., 2015). With twice daily feeding, it is worth starting slowly and working your way up to between 6-8 litres per day depending on the calf.

My calves stay in the same pen until weaning, is it worth mucking out every 30 days?

Mucking out mid-way through the batch is certainly extra work. Our study into growth rates found farms cleaning out more frequently (at least every 30 days) had higher growth rates than those cleaning out less frequently, so it is worth considering whether the extra effort cleaning out would be worth it for your system.

Would you recommend cleaning cow calving pens after each calving?

If this is possible in your system, this is a great idea for calf hygiene as they are unlikely to be exposed to pathogens from other adult cows. If calving yard surfaces are concrete then make sure there is no chance of cows slipping when the bedding pack is removed.

Thoughts on the research suggesting that feeding more than 4 litres BID to dairy heifers can lead to metabolic problems later in life? Should we be splitting this into 3 feeds?

There is some evidence that 4 litres per feed (twice per day) can result in metabolic issues, however these issues are no longer present at 300 days of age (Yunta et al., 2015). A calf suckling from its mother would have lots of small feeds, so ideally it would be worth splitting into as many feeds as possible. However, multiple feeds per day obviously comes with a much higher labour cost if feeding manually.

The shed temperature during the first month of life – is there a mean shed temperature over that month? Does that not hide the temperature variation between day and night?

The graph showed the mean shed temperature over time, so yes this would hide temperature variations between day and night. We did also analyse day/night differences as well as a wide range of temperature measurements/ratios and found the mean temperature in the first month of life had the greatest effect on daily liveweight gain.

How can I test colostrum for bacteria levels?

Testing can be arranged with your veterinarian. Take colostrum samples from your feeding equipment and freeze as soon as possible after sampling. A laboratory can then test these samples to determine the number of bacteria present per ml of colostrum.

What level on a refractometer should we be looking if testing blood?

Using a refractometer on calf blood serum can give a good estimate as to whether the calf has received adequate immunity from colostrum. Calves with less than 7.8%, or a serum total protein of  less than 52g/litre are likely to not have acquired enough immunity from their colostrum (Zakian et al., 2018). When using a refractometer to measure colostrum quality, the following thresholds can be used (Buczinski and Vandeweerd, 2016):

• Good quality (Use): ≥22%
• Intermediate (supplement): 18-22%