Rural Diary June

Rural Diary June 2019

PGG Wrightson's monthly technical guide to assists farmers with planning on-farm activities, to maximise productivity and grow their business.

Calf rearing takes centre stage in this June edition, and we cover a range of nutrition related topics to help calf feeding decisions. On the animal heath front we have articles on pre-lamb vaccinations and lice control. Also, turn to page 12 for tips on growing a lasting lucerne crop.

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Liquid feeding in calves

A successful calf feeding framework transitions the calf from a pre-ruminant reliant on milk, to a healthy weaned calf with a functional rumen able to digest pasture. In this article, part one of a two-part series, the focus is on the intensive liquid feeding phase of the calf feeding framework.

Successful calf rearing is informed by the following key feeding objectives: healthy calves, optimal growth, transition to becoming a functional ruminant and successful weaning.

The first and foremost component to ensure healthy calves is optimisation of passive transfer from the dam via provision of good quality, gold colostrum at a rate of 10 percent of Birth Body Weight (BBW) ideally within 6 to 12 hours after birth. Continued feeding of transition milk (second and third milkings after calving) is recommended in the first few days of the calf’s life. Transition milk is incredibly rich and helps keep young calves healthy and well nourished.

As demonstrated in the framework, all calves of all ages require free choice access to good quality, clean, palatable water. Daily water intake of a calf is 15 percent of body weight, for example, a 40 kg calf requires 6 L per day, this is in addition to liquid feed. All calves also require free choice access to a quality, high protein calf starter meal. 

In the first three weeks of life, the calf’s rumen is physically underdeveloped and physiologically non-functional¹. At the same time, the calf is unable to regulate its own body temperature² so the best choice to achieve optimal growth is liquid feed. There are several options available: casein-based milk replacers, whey-based milk replacers, waste milk, transition milk, or whole milk. All options make for excellent calf feed. The choice of which liquid feed works can be determined by what is available and suitable for the calf-rearing programme.

During the first three weeks of age, the more liquid feed consumed by a healthy calf, the more growth can be expected. On that basis, the recommendation to optimise growth is to provide liquid feed at 17 to 20 percent of BBW. Theoretically, this would translate to free choice consumption for the first three to four weeks of life. After the animals are bigger and more robust, the liquid feed component can be reduced to 10 percent of BBW (that is, one feed per day).  This reduction in liquid feed will also serve to encourage starter intake.

In the first ten to fourteen days of age, a little calf is likely to consume approximately five percent of body weight per feeding session. To optimise intake and growth, increasing feeding frequency is recommended. 

Attention to detail becomes incredibly important in sheds where there is variability in weights of the calves being fed. For example, if little Wagyu or Jersey calves (20 kg BBW) are fed the same regime as a Holstein Friesian calf (40 kg BBW), the risk for nutritional scours and rumen drinking³ in the smaller animals is high.

Don’t miss out on the second article of this series discussing rumen development in next month’s Rural Diary.

For more assistance with reviewing the liquid feeding programme on your farm, contact your local PGG Wrightson Technical Field Representative.

¹ Kahn et al., 2011 JDS 94:1071-1081.
² Arieli et al., 1995 JDS 78:1154-1162.
³ Rumen drinking is caused by the failure of the reticular grove reflex, and results in rumen acidosis in calves on a liquid diet. J. Quigley CalfNote #113.

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Avoiding problems from the start

The first weeks of calves’ lives set them up to be able to grow to their genetic potential and have a productive future. Here are some tips to ensure the right foundations are established from the start. 

New Zealand studies¹ have shown that at least 25 percent of calves fail to suckle effectively to get enough quality colostrum in the critical first 24 hours of life, resulting in Failure of Passive Transfer (FPT) of antibodies from the colostrum. Best practice calf collection should be three times daily, with research showing once or twice daily collection resulting in significant numbers of calves with FPT. This is particularly relevant when bad weather occurs as calves cannot thermoregulate (control their core body temperature) so they need even more milk.

Collect calves into clean trailers with non-slip rubber matting, preventing slipping or sitting in mud and faeces. Spray navels with iodine based sprays both into the trailer and again when arriving at the shed. Clean the trailers out on a regular basis and drive at a speed that calves can stand.

When transporting calves four days and older, it is best to give an electrolyte feed on arrival at the new property and only a small milk feed of 1 to 1.5 L of new milk source or Calf Milk Replacer (CMR) to avoid nutritionally stressing the calf in the first 12 hours after arrival.

Calf rearing sheds should be dry, draught free and have good drainage. Bedding should also be dry and preferably at least 100 mm deep. Top up on a regular basis to ensure urine and faeces are buried, reducing disease risk. Solid partitions between pens stops calves licking and also help to reduce disease spread. All pens need access to fresh water. A hospital pen at one end of the shed or, better still, in a separate facility for isolation of sick calves is recommended. 

Reinforce with staff that they can be a cause of disease spread. Have a foot bath with disinfectant, for example Virkon, before entering the sick pen and ideally have one person in charge. Have a thermometer to monitor calves to determine severity of disease (seek a Vet’s help if temperature is greater than 39.5 degrees Celsius). 

Remember, being prepared and having a plan that all staff are aware of can greatly improve the enjoyment of your calf rearing season and result in healthy calves. 

For more advice on all aspects of calf rearing, speak to your local PGG Wrightson Technical Field Representative, or visit the PGG Wrightson YouTube channel.

Written by Jason Leslie

 
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Healthy ewes make for healthy lambs

The muster prior to lambing is the last opportunity to influence ewe health, milk production and lambing performance. Feed levels and condition score are set, so what else can you do to maximise your return at weaning?

Knowing whether ewes are carrying singles or multiples enables accurate feed allocation. It also allows pre-lamb treatments to be tailored to the ewes that need them. Those with poor condition (body condition score of less than 2.5), lambing hoggets or carrying multiples may benefit from longer worm protection. 

Using a long acting, broad spectrum drench such as Cydectin® Long Acting Injection for sheep helps protect against Teladorsagia (Ostertagia) circumcincta for 112 days, Haemonchus contortus for 91 days and Trichostrongylus colubriformis for 42 days. A 2017 New Zealand trial comparing long acting treatments found that poor conditioned ewes treated with Cydectin Long Acting were on average 3.2 kg heavier at weaning than untreated ewes, and their lambs weaned 2.6 kg heavier¹. Other New Zealand trials have demonstrated the negative effects parasites have on ewe milk production and the subsequent impact on lamb growth rates2,3.

For ewes that don’t need the length of action offered by Cydectin Long Acting, Eweguard® is a medium-acting product that provides at least 35 days protection against Teladorsagia (Ostertagia) circumcincta and seven days against Trichostrongylus colubriformis. Conveniently, it is also a 5-in-1 clostridial vaccine, plus prevents cheesy gland (caseous lymphadenitis) and is available with or without selenium. New Zealand studies have shown Eweguard treated ewes have less dags⁴.

All sheep, including rams, should get a clostridial vaccination annually. For ewes, this protects them while on crops, in muddy paddocks and when giving birth. It also allows them to pass on protection to their lambs via the colostrum when they start to feed suckle, maximising their survival. 

Ewes should be vaccinated three to four weeks pre-lamb, and their lambs should receive their first vaccination at tailing followed by a booster at weaning. Weaning is often a time of high risk of death from pulpy kidney disease, so vaccination of the lambs is important to increase the chance of survival. 

Your local PGG Wrightson Technical Field Representative can offer more information on the treatments you can add to your pre-lamb management to get a bumper crop of healthy, fast growing lambs this spring.

Supplied by Zoetis New Zealand

 
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Growing a long-lasting lucerne crop

The key to growing a high yielding, long-lasting lucerne crop that provides high quality feed is dependent on good weed control and plant nutrition.

A successful crop of lucerne can last many years as long as it is well managed and good weed control is achieved. This can be done with a combination of spraying, mowing and grazing.

In mature crops of lucerne, weed control should be done during winter when the crop is dormant to reduce damage. Walk the paddocks during late autumn and identify weeds and their numbers. During mid-winter, use a mixture of a contact burn-down spray (containing paraquat) and another residual herbicide (usually containing atrazine) to brown-down the weeds and leave a residual herbicide layer on the soil surface to kill any newly emerging weeds. Remember, this can only be done on established crops that are over 12 months old as the spray can damage younger plants with smaller root systems.

Monitoring the crop for weeds during the spring and autumn is also important on established crops as other more selective herbicides can be used on specific weeds throughout the year. Don’t forget the use of the mower. Removing annual weeds before they set seed is a good form of weed control during the season.

Keeping your lucerne crop healthy and productive helps it compete with weeds as well. Over time paddock fertility drops and pH levels decrease. It is important that nutrients, especially potassium (K), are replaced if you are grazing or cutting and removing the crop. Ensure regular liming to keep pH levels above 6.0. 

In most situations, the end of a lucerne crop’s life is when the battle is lost against weeds that limit production and palatability. It is then time to spray out and put in a new crop.

For more information on weed control in lucerne, contact your local PGG Wrightson Technical Field Representative. 

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