The importance of the first few hours of a calf’s life and the long-term implications for the newborn animal cannot be underestimated. Our Head of Ruminant Nutrition, Maeve Regan has put together a list of our most frequently asked calf rearing questions and answers to help you set your calf up for lifetime success.  

What should be considered when it comes to colostrum management? 

The successful passive transfer of immunity from the dam to the calf via colostrum is the cornerstone of calf rearing. Research indicates that herds that achieve high levels of passive transfer (100%) result in significantly less mortality rates (4.95%) when compared to poor levels of passive transfer (70-75%), resulting in mortality rates of 9.31%.

High standards of hygiene are necessary when collecting, feeding, and storing colostrum, with research indicating that colostrum contaminated with dirt/bacteria results in reduced antibody absorption. A Teagasc Moorepark study involving 48 commercial farms highlighted that stomach tubes and bottles with teats had the greatest quantity of bacteria present. The pooling of colostrum on farms should also be avoided to reduce the risk of disease transfer within the herd, as well as dilution of high-quality colostrum.

What are the key elements to consider when choosing a milk replacer? 

Firstly, it must contain a high level of dairy content. Dairy-derived protein sources include whey and skim powder. Research indicates that from 0-3 weeks of age, milk-derived proteins are the only proteins a calf can digest efficiently. Plant-based ingredients/vegetable sources of protein are less digestible to the calf and therefore reduce the nutritional quality of the milk powder. Higher levels of fibre in a milk replacer, typically indicate a greater percentage of plant protein. This year where margins are tight, high vegetable-based milk replacers may appear ‘good value’, however, comparative average daily gains to whole milk shouldn’t be expected in the early weeks of life.

Our Vitalac Red and Blue Calf Milk Replacers contain a 89-90% dairy content, offering a well-balanced level of highly digestible fat and protein, using carefully selected high quality dairy ingredients. These quality ingredients are further enhanced using advanced techniques such as Low Heat Spray Cooling Technology so that the ingredients don’t denature during the manufacturing process.

What concentration of milk replacer should I be offering calves?

When it comes to milk replacer, we are trying to replicate in the calf’s diet the role of good quality whole milk (3.4% Protein + 4.3% Butterfat + 4.8% Lactose = 12.5% Milk Solids). Calf milk replacer is therefore generally fed at 12.5%. This equates to 125g of powder being dissolved into 875ml of water, to make up 1 litre of milk. When 6 litres of milk are being offered to the calf, 750g of powder per calf per day is being used. For accelerated feeding programmes, concentrations can be increased to 15%.

Does the environment calves are reared in affect their nutritional needs?

Having calves warm, comfortable, and feeding well is what we should be aiming for. Your calves will pay you back for getting this right. A cold environment will result in vital energy consumed by the calf being burnt to keep itself warm. In cold sheds, try to create a warmer micro-climate for calves, such as dropping a canopy area against the back wall, or using large square bales to protect calves from draughty areas. When looking at the calf pen, there should be an even distribution of calves across the lying area. Where calves are often lying bunched against the back wall or corner, the shed may be too cold.

A calf spends approximately 80% of its time lying down, therefore it’s essential to provide a deep, warm, dry bed. When giving the shed a bedding score, a good rule of thumb is to place your hand firmly onto the bedding. The straw around your hand should be up to your elbow. The base of the bed also needs to be dry – kneel on the bedding and when you stand up your knees should be dry.

When it comes to nutrition, for every degree below 10°C, an extra 2% milk replacer can be offered to compensate.

Apart from milk replacer, what other sources of nutrition should the calf have in its diet?

Milk should be seen as a feed rather than as a drink. Water is an often-forgotten source of nutrition in calf rearing and is a cheap ingredient for hydration and rumen development. Fresh, clean water must be always available to calves. Where water is limited, this will restrict dry matter intakes. Dirty/contaminated water sources can also be linked to bloat.

Fresh clean straw is also another critical component in early rumen development and must be offered ad-lib as a source of fibre in the diet. Straw is preferable to hay. Silage/haylage should never be offered to calves pre-weaning.

What sort of ration/nut should be offered to calves during the rearing period?

Starter rations should be introduced from 3 days of age and will play a vital role in rumen development and early weaning. They should be sweet-smelling, molassed and contain cooked ingredients – these 3 factors will help aid intakes and digestion. Once intakes start to increase (normally greater than 250g), a typical 18% crude protein calf ration or nut can be offered to calves.

Once calves are turned out to grass, or have grass in the diet, a 16% crude protein concentrate will suffice.

When should I consider weaning my calves and how long should they be on milk?

A 70-day calf rearing period is the norm on farm. However, to have a uniform group of calves, weaning should ideally take place on a weight basis, coupled with concentrate intakes rather than an age basis. The target when weaning calves is to have doubled in live weight from birth to weaning (40–80kg in 10 weeks). However, weaning on a weight basis alone can create a false sense of security in terms of how ready calves are for the next stage of nutrition.

The success of the weaning process and the weeks thereafter will hinge around how the rumen has developed over the first weeks of the calf-rearing period. Weaning should never be considered until calves are consuming at least 1.5kg concentrate/hd/day in grouped pens – signalling that the calves’ dry matter intakes can cope with the transition to a 100% solid diet.

Further Advice

For further calf rearing advice or to learn more about our milk replacer range or post-calving minerals, contact your local Agritech Sales Advisor.

Firstly, weaning should only ever occur once calves are consuming at least 1.5 kg of concentrate per head per day in group scenarios. Alongside this, gradual weaning is advised to minimise stress levels in young calves and to allow them to increase dry matter intakes over a prolonged period.

During the first grazing season, heifer calves should have a good consistent growth rate of 750g /day or 20kg/month. Calves should always have access to high-quality grass, and depending on target weight gain and grass availability, a quality concentrate supplementation may be required. Typical advice is to feed meal at least 6 weeks post-weaning/turnout and reintroduce meal again in autumn if desired weights are not being met.

Setbacks that occur now or over the first grazing season will result in heifers struggling to meet target weights in the future and can result in these heifers not making it to the parlour.

What is Summer Scour? 

Year on year, in the proceeding weeks after turnout to grass, cases of calves suffering from setbacks are reported, typically described as Summer Scour Syndrome or calf wastage.
Lush grass is very high in oils like CLA (conjugated linoleic acid), sugars and potentially nitrogen, and to a young undeveloped rumen this can be hard to adjust to. In addition, low covers of grass have very little fibre, which is a key substrate for good rumen health.

It’s often asked why Summer Scour Syndrome was not an issue until recent years, and the short answer is that we are victims of our own success. Grassland management has dramatically improved over the past number of years. Calf rearing has also improved, and we are typically weaning calves at 8-10 weeks of age. It is also worth noting that ditches are now typically fenced off to youngstock where historically they would have been used as a source of fibre by calves.

In severe cases or if prolonged, rumen function can be severely impaired and B vitamins may no longer be manufactured by the rumen, resulting in blindness and ‘star-gazing’.

Note: Where poor thrive/scouring is an issue at grass post-turnout, Coccidiosis should be the first port of call to rule out.

Avoiding the issue: 

Ideally, the rumen is developed over the milk feeding period/pre-weaning by offering ad lib access to concentrates (18% Crude protein crunch/nut), and clean fresh straw to reduce your risk of Summer Scour Syndrome.

Below are several management practices that can help combat against the onset of Summer Scour Syndrome symptoms this season, a few which will be farm/system dependent:

1. Offering concentrates in the weeks post-turnout will help to avoid overindulging on rapidly digestible lush grass. Hungry calves are more likely to gorge on lush covers.
2. During periods of rapid growth, avoid letting calves into low covers of grass. Until rumens are well developed and luxury uptake of nitrogen is not a problem, target covers of at least 1,200-1,400 kg DM/ha for 8-10 weeks after turnout.
3. The use of Agritech’s Rumicare in meal pre and post-weaning will help the buffering capacity in the rumen, decrease the risk of acidosis/ruminal upsets during the transition period and promote positive bacteria populations in the rumen (typically included at 2%).
4. Give access to grass and indoor accommodation simultaneously prior to full-time turnout to ease the transition to grass.
5. Offer a fibre source post-turnout. Round feeders are an option to allow access to clean dry straw.
6. Use strip-wire allocations. Strip-wires allow for less selective grazing and force calves to eat stem content along with the leaf.

More Information: 

For more information on reducing the stress of weaning on your calves, contact your local Agritech Sales Advisor.

Newborn calves are born with undeveloped rumens, yet they will spend more of their lives as fully functioning ruminants. The main objective is to assist the transition from pre-ruminant to ruminant by developing the rumen as much as possible before they are weaned off milk, so that they grow to be cost-effective forage consumers that are efficient at converting feed to milk or meat.

Rumen development begins within the first few days after birth and is advanced by exposure to healthy bacteria from the environment and the consumption of solid feeds – concentrates and straw (preferable to hay). Concentrates should be introduced from three days of age (an 18% crude protein calf starter ration/nut ideally) alongside free access to fresh clean water and high-quality clean straw ad-libitum (no haylage or silage).

Source: Penn State Extension

Considering Weaning 

Weaning on weight basis alone can leave a false sense of security with how ready calves are for the next stage of life/nutrition. The success of the weaning process and the weeks thereafter will hinge on how the rumen has developed over the first weeks of the calf-rearing period. Weaning should never be considered until calves are consuming at least 1.5kg of concentrates/hd/day in grouped pens – signalling that the calves dry matter intake can cope with the transition to a 100% solid feed diet.

Concentrates should be offered ad-lib while on milk but tracked closer to weaning to ensure the group is consuming adequate levels to allow weaning to commence.

Calf Rearing Advice: 

For further advice on calf rearing and calf milk replacer, contact your local Agritech Sales Advisor.