Can you harm colostrum quality by re-warming the colostrum?

Colostrum fed close to body temperature (38 degrees) will help keep calves warm and allows for optimal curding and digestion.

When reheating milk or colostrum, it should be done slowly and carefully, as the proteins will start to denature and lose their 'magic' if heated over 65 degrees.

Clostrum can be fed cold, but calves will have to use energy to heat it, and until it's warm the curding profile will be slightly different.

What is the best antiviral disinfectant for spraying pens?

Most disinfectants will be effective against bugs on hard surfaces, but the main source of pathogens is in the bedding, which can't be disinfected.

Keeping bedding clean and dry, by topping up, if necessary, can greatly reduce the risk of disease. Hard surfaces should (ideally be cleaned, and) be sprayed at least once a week with disinfectant.

What's the milk price cut-off everyone uses to decide if they feed from the vat or powder?  And what's the recommended age/weight to change to once-a-day feeding?

There are quite a few considerations so there is no specific price that everyone works too.
We would recommend is to calculate your individual farm's savings, based on your milk solids and number of calves being reared, using one of our online calculators:

Ancalf Calculator >

Ancalf Finisher Calculator >

Best practice recommends twice a day feeding to at least 3-4 weeks. 

Proposed standards can be found here >

What's the ideal age to start transitioning calves to paddocks?

The longer you can provide calves with shelter, the better. A fully developed rumen generates a lot of heat via fermentation, but it takes several months to get to that stage. Allowing calves access to pasture from an early age gives them more time to get used to eating grass and provides them with mental stimulation to assist their development.

If you've got the capacity to give calves access to pasture from birth that's great, though they probably won't venture out much for the first few days.

Be aware that as soon as calves start eating grass, they're also ingesting parasites, so start thinking about drenching needs from about a month after they begin going outside. Even when they're fully moved out of the calf sheds, calves will appreciate having access to some form of shelter from the weather.

What are your thoughts on feeding reject/treatment milk to replacement calves?

It's not considered good practice to feed waste milk to calves. Ideally the milk from cows under treatment should be kept separate from cows in the colostrum mob, but we acknowledge the practical difficulties on some farms.

This article from DairyNZ references this article from the European Food Safety Authority about the risk of antimicrobial resistance from feeding milk from cows under treatment to calves.

What are your thoughts on freezing surplus gold colostrum for later use?

You will lose some activity as the IgG molecules are large proteins and can easily denature or be damaged. Also, the freezing itself, the forming of ice crystals are like millions of sharp little knives, can damage the proteins (incl. IgG).

They also have to be careful thawing it. Don’t microwave it and don’t put it in a bucket of hot (boiling) water – any temperature exposure over body temperature can potentially denature proteins, esp. antibodies (IgG). 

We often recommend keeping a store of colostrum in the freezer, this is not ideal for the reasons I mentioned, but it is much, much better than feeding no colostrum or “dirty” colostrum, but as always clean fresh colostrum directly from the mother is best.

Based on best practice how old does a calf need to be to introduce meal / hay?

Solid feed should be available from birth. Initially, calves will just mouth at it and won't eat enough to have an impact on their nutrition, but it gets them used to the taste and helps seed microbes into their developing rumen.

The carbohydrates in meal-like feed ferment into volatile fatty acids that rapidly drive the development of the rumen surface. High fibre feeds have a "scratch factor" that helps separate out the developing papillae, increasing the nutrient absorbing surface area and helping develop the muscles of the rumen. For optimal rumen development, calves would have access to both types of hard feed.

Where are we heading with the new animal health laws coming in? The discussion document suggests calf rearers need to feed 20% of body weight in the first 3 weeks...

This is one of the pieces of the new code that has generated the most reaction from farmers, and I suspect will receive a lot of attention in the public feedback to MPI. Remember this is still a draft code under public consultation, and you can provide feedback until the end of June 2022.

If you've got the time, the "Code of Welfare Evaluation Report" that accompanies the proposed code is useful to help understand the thinking behind any changes to requirements.

For the specific standard in this question, the reasoning is that calves fed less than 20% of their body weight over two (or more) feeds per day will experience hunger, and won't be able to compensate by eating more solid feed. When they're over three weeks and their rumen is more developed, they will be able to compensate, and the 20% requirement goes away.

What are your thoughts on the process of feeding pooled colostrum? How could we make it more efficient?

Pooling gold colostrum (from 1st milking) is a good way of making sure it contains a wide range of antibodies. Only high-quality (brix >22%) colostrum should be pooled, as mixing in lower-quality colostrum will dilute antibodies too much.

The storage vessel for pooled colostrum should be kept clean, this means regularly scrubbing to remove surface fat that bacteria like to grow in.

When testing our herds (600 cows) gold colostrum quality we found only 22 met the required brix levels. Any idea why?

This is expected. Colostrum quality is affected by a number of factors including age and health of the cow, but most significantly the time from calving to first milking.

Modern dairy cows produce a lot of milk, and as soon as they calve the milk going into their udder begins to dilute the colostrum that was already sitting there.

You can compensate for lower quality colostrum by feeding more of it, but most calves can't physically drink that much.

Any thoughts on ‘optimum’ time to remove calf from the cow?

There is ongoing research in this area, as there isn't a clear answer at the moment. Taking them shortly after birth is probably better from a cow-calf bonding perspective, but you're now responsible for ensuring the calf gets colostrum.

Ideally, you'd assess on a case-by-case basis; if the calf looks vigorous and is drinking then it can probably stay with the cow longer, but the longer you wait before giving colostrum the less effective it is.

Do you have any stats on putting covers on calves’ verses none? Also, what are the potential gains, weight wise, using fortified milk vs using straight transition milk?

The younger a calf is, the more susceptible to cold stress they are. Most calves are housed during the first few weeks of life when they are most susceptible to cold stress, and a well-designed calf shed with deep bedding will allow them to keep warm while housed.

A young calf housed at 0 degrees will need 50% more food than one housed at 20 degrees in order to maintain the same growth rate. Once outside, calves will grow faster if they are sheltered from wind and rain. This can be achieved with planting, built structures, calf coats, or a combination. Most studies into the effect of covers on calves are in housed systems where calves aren't exposed to wind and rain.

They usually find no difference in performance or slightly better weight gain in jacketed calves, but that the jacketed calves don't have to drink as much. It would be good to see some more research conducted into this question with older calves under New Zealand conditions, as exposure to wind and rain are likely to increase calves' energy demands.

What are your thoughts on tube feeding every calf that comes into the shed & brix tested colostrum?

This could be one way to ensure every calf gets enough colostrum but is a lot of work and carries some risk to the calves. Depending on how many times a day you're collecting calves, they may have already suckled their dam and be vigorous enough not to need tubing.

Many calves will drink from a teat and not need to be tubed, though you may not have time to teach them when they first come to the shed.

Before deciding to tube every calf, check your current system for rates of Failure of Passive Transfer (will require blood testing around 12 young calves). Your current system could be working fine.

How many days should calves stay on colostrum?  How many days should they stay on twice-a-day before moving to once-a-day?

No more than three days on full colostrum. After the first 24 hours the calves will no longer be able to absorb the antibodies in the colostrum, but it's still a very high energy food and has a locally protective effect on the gut. Because it's so rich though (contains twice the protein of whole milk), it can cause a nutritional scour.

For best results, calves should be fed milk at least twice a day for at least four weeks.

The proposed revision to the Code of Welfare: Dairy Cattle would make it a requirement that calves be fed at least twice a day for the first three weeks of life - public consultation runs until the end of June 2022.

And what is the best age to start transitioning to the paddock?

Calves will start eating pasture as soon as they are exposed to it. The sooner they start eating solid feed (even if it's only a few nibbles to begin with) the faster their rumen will develop. Calves are innately curious and will play and explore if given the opportunity.

If you're able to provide some access to pasture from an early age that's great, our farmers tell us that most calves start to be fully outside from around six weeks of age, but some access is usually allowed before then. When they're out on pasture they will still benefit from some form of shelter, either natural or constructed.

How many litres of water a day should a calf drink when in the calf shed?

Even newborn calves that aren't eating any hard feed will drink around 750ml/day, and this increases as they eat more dry feed. As hard feed increases, so too does voluntary water intake, and four-week-old calves who have access to hard feed from birth will be drinking around three litres of water.

Water intake is another driver of rumen development, meaning that calves who have had ad lib access to water will be ready to wean earlier than if water was restricted.

What is Fonterra's position on once-a-day milk feeding of calves?

Fonterra accepts the scientific opinion that very young calves are unlikely to be able to meet their nutritional needs on OAD feeding for the first few weeks of life.

If left on their dam, calves will drink up to 12 times a day, and their total intake will be much higher than it's possible for them to consume in one feed.

It is well established that the more milk calves drink in total, the better grown they will be and the more they'll produce when they enter the milking herd.

Once you move to once-a-day milk feeding, is it best to feed morning or afternoon?

It's most important that the timing of the OAD feed is consistent, but some people say that because of the natural daily rhythm of calf activity, feeding milk in the morning allows calves more "active" time to eat hard feed during the rest of the day. It's unclear if this has any scientific basis.

If the calf gut closes to the healthy defence parts of colostrum after the first 24-36 hours of life, is there any health benefits of feeding colostrum after this time (as compared to normal whole milk)?

The antibodies in colostrum won't be absorbed by the calf after the first 24 hours, but they will still bind to pathogens floating in the intestine and reduce the risk of the calf getting sick.

While this can have some benefit for the first couple of days of life, colostrum is too rich to use as a primary feed after that and can cause a nutritional scour.

How much straw should be fed per calf? 

Calves perform well if given free access to good quality forage. Therefore, free access to forage should be available from a young age. This can be good quality hay, silage or access to pasture.

Forage is important for rumen development and the establishment of microbiota required to ferment forage at weaning.

AgResearch trials have demonstrated that calves can be successfully reared without using concentrates on a good quality forage-only solid feed diet (e.g. ensiled Lucerne or grazed pasture; >10 MJ/ME and >16% crude protein) without adverse effects on lifetime performance in dairy-beef
calves. This can be successfully implemented in calves fed a high milk allowance (e.g. >6/L day).

What is the ideal weight to wean?

The best time to start implementing “step-down weaning” will depend on your milk feeding system, but three good rules of thumb are:

• Weight-for-age target met (common weights used for weaning are 70kg for Jerseys, 80kg for Crossbreds, and 90kg for Friesians).
• Eating more than 1kg of meal or 2kg of good quality forage (e.g. pasture) per day.
• Calves are in good health and not receiving animal health treatments.

A calf’s rumen development is the most important factor to consider when making a weaning decision. The only way this can be assessed is by measuring the amount of solid feed your calves are readily eating, which should be at least 1 kg of meal or 2 kg of pasture per day when commencing the weaning process.

What is a good mix rate to mix CMR with milk?

Where whole milk (including colostrum) availability is limited, or not cost-effective, Ancalf can be used in conjunction with whole milk to meet the daily feeding requirements of the calf.

Ancalf powder should be mixed with warm water at a rate of 150g/L and then combined with whole milk to reach the desired feed volume. A common ratio is 50% whole milk and 50% Ancalf.

Where a concentrated Ancalf feed is required for once-a-day systems, Ancalf powder can be added directly to the whole milk at a rate of 150g/L of whole milk.

Note: a typical litre of milk is equivalent to 150g of Ancalf powder.

What are your thoughts on an ad-lib feeding system vs twice a day structured feeding?

Research has shown that increasing milk supply (ranging between 4-10 L/day) of either vat milk or milk replacer during the first 2 months of life promotes growth and is beneficial to the development of various organs (e.g. gut and mammary gland).

Further, international studies have shown that accelerating pre-weaning growth through improving milk supply can promote greater lifetime milk production and studies in New Zealand have shown improved growth and thus reduced time to cull and environmental impact without compromising meat quality in dairy-beef heifers.

Therefore, feeding calves more milk (around 20% of their initial body weight, 6-10 L/day for calves with 25 to 50 kg of initial body weight) during the first 2 months of life will not only improve growth and organ development of the calves but could potentially enhance the lifetime performance of the calves in commercial herds.

Studies have shown that ad-lib feeding increases calves' milk consumption i.e., more than a high milk allowance (20% of a calf's body weight).

What’s your thoughts on whey instead of casein-based calf milk replacer?

The younger a calf is, the closer its diet should be to whole milk. Once they’re over four weeks old their digestive system has developed enough that they can cope with a wider variety and quality of feeds, but there are growth and performance impacts that can come from feeding poor quality feeds to young calves.

Whole (bovine) milk consists of 3.3-3.5% protein which consists of 2 types of protein – caseins (~80% of the milk protein) and whey (~20% of the milk protein) proteins. Caseins are large proteins that curd and are what clump together and solidify when you make yogurt or acidify milk. Whey proteins are much smaller, and do not curd. The differences in curding behaviour between casein and whey affect the transit rate of milk replacer through the digestive tract and therefore the performance of the calf.

Scientific research suggests that a curding milk replacer can;

• Increase growth rates.
• Reduce health issues e.g. scours.

What is the optimum growth rate for calves pre-weaning?  What time frame/ weight would you find best for starting the weaning process?

Approximately 1KG per day (850-900g/day from our trial). Although growth rates, like weaning weights, will relate to the type/breed of calves being reared. A smaller jersey calf may not grow at the same rate as a larger beef calf. It is therefore best to consider the following when weaning …

The best time to start implementing “step-down weaning” will depend on your milk feeding system, but three good rules of thumb are:

• Weight-for-age target met (common weights used for weaning are 70kg for Jerseys, 80kg for Crossbreds, and 90kg for Friesians).
• Eating more than 1kg of meal or 2kg of good quality forage (e.g. pasture) per day.
• Calves are in good health and not receiving animal health treatments.

If using whole milk, does it help to add (say) apple cider vinegar in calf milk bins to curdle milk? Any other product recommended?

This is not necessary if the whole milk is of good quality and hygiene is good.

If the feed is whole milk/a whole milk powder (casein based) milk replacer, the casein component will curd naturally in the acid environment of the abomasum, slowing digestion and allowing salivary enzymes time to break it down.

How long from decision to wean (target weight met and solid feed consumption met) to weaning?  Do you reduce feeds over a week or go cold turkey?

Prior to weaning monitor calves closely to establish whether all calves are consuming solid feed (i.e. eating at the feed trough and demonstrating rumination behaviour). Monitor closely for signs of illness and consider separating and reintroducing milk for any calves that don’t seem to be coping.

Once a day feeding with restricted milk allowance can be used as a weaning method. Low milk allowance calves can be weaned over 3-4 days, while high milk allowance calves (>6L/day for an average size calf) need 2-3 weeks, to increase solid feed intake and thereby help prepare the rumen for better post-weaning performance.

Ideally, the step-down weaning procedure should be implemented in 4-5 steps where 20-25% of the milk offered is reduced every 4-5 days. If using automatic feeders, a 5% linear reduction of milk offered daily over 20 days is ideal.

How do people best mix the milk replacement powder without getting all the lumps?

Ensure that half the water is used for adding the powder, add the required amount of CMR and whisk, top up to the required volume and whisk again. Ideally feed at 38-40 degrees Celsius.

Do you know if there is a purchasable option for gold colostrum?

If you don't have access to gold colostrum Jump Start full cream colostrum could be a good option.

Jumpstart is a replacement colostrum powder designed as a natural supplement for newborn animals. It provides IgG antibodies that are essential to form the immune system of young animals.

• Contains 9% Immunoglobulins (IgG’s) which are the initial building blocks of health and immunity in ruminants.
• Contains vital growth performance nutrients Vitamin A, E and Niacin.
• Formulated as a complete first feed.