February 2019 Monthly Management

Calf Rumen Development

When a calf is born, it has an underdeveloped digestive system, i.e. they have the same four stomachs as a mature cow but the rumen is significantly smaller and inoperative. The abomasum makes up 70% of the total volume and the rumen accounts for less than 30%. This is because diet of a young calf consists of primarily milk. Liquid feed bypasses the rumen via the oesophageal groove and enters the abomasum (true stomach) for digestion at this stage of the calf’s life.

The primary factors determining ruminal development include microbial growth in the rumen, fresh water and solid feed intake.

Microbial Growth

The inside of the rumen contains many finger-like projections called papillae. These papillae increase the surface area and absorption of nutrients in the rumen. Papillae development is stimulated by the end products of microbial fermentation called volatile fatty acids (Butyric and Propionic acids). In the young calf, there are no microbes present in the rumen but as the calf grows these become fully functional and populations increase as the diet adjusts to solid feed.

Fresh water

Calves should have access to fresh water from 4-5 days of age. While stimulating solid feed intake, water is also required by the rumen microbes to ferment feed and to grow. Water consumed must be ‘free water’ and be available to the rumen microbes - milk or milk replacer fed to calves should not be considered as beneficial to rumen development as these liquids enter the abomasum.

Solid Feed Intake

To promote early rumen development, the most important factor is early consumption of solid feed. Best practice is by offering a quality calf starter ration from three days of age onwards. A fresh (daily feed), palatable calf starter ration with cooked ingredients contains the correct forms of carbohydrates that are needed to bring about the butyric and propionic acids that stimulate rumen and papillae development. Fibre sources such as straw and to a lesser extent, hay, help increase rumen weight and size, however, these feeds do not promote papillary development.

Rumen Development: Milk only
Small physical rumen capacity and the smooth surface appearance indicates that there is very little papillae development present.

Rumen Development: Milk + Hay
The calf fed milk and hay has a large rumen in size but clearly has stunted development, with light color and very little papillae growth.

Rumen Development: Milk + Straw + Concentrates
The concentrates-fed calf has a healthy, properly developing rumen. A healthy rumen has a dark coloration plus the papillae are numerous and visible without magnification.

Supreme Cooked Calf Muesli

Drinagh Supreme Cooked Calf Muesli - the best quality calf starter available to feed to your calves

This superior quality calf muesli will give your calves the best possible start for rumen development. The finest ingredients are cooked, flaked and blended to ensure palatability and stimulate uptake of feed by young calves.

Fortified with Bioplex trace elements, elevated levels of Vitamin E and B Vitamins which collectively support immunity and maximise performance.

Spring Fertilizer

Current grass covers on farm are very good. To maintain good growth rates throughout the spring, fertilizer application must be managed correctly. The aim is to have 70 plus units of nitrogen (N) out by April 1st.

Slurry: The efficiency of slurry utilization is far greater in the spring than other parts of the year. This spring, while conditions have been good for slurry, the amount of grass in paddocks has made application more challenging. In this situation the trailing shoe, dribble bar or swivel plate will do less damage to grass covers compared to the conventional splash plate. Paddocks grazed in February could receive 2000 gallons of slurry up to early March if trafficability isn’t an issue after grazing.

Fertilizer: On farms that applied urea in January, the next application should be 4-6 weeks after the first application, 30-35 units of urea or 18 6 12 + S per acre should be applied in early March. Phosphorus is one of the major elements in driving spring growth and has the effect of kick-starting grass growth. The selection between 18 6 12 +S or urea at this stage is down to weather conditions at the time of spreading. Urea is safer than ammonium nitrate-based fertilisers (i.e. C.A.N.) when weather conditions are poor because ammonium nitrate-based fertilisers are more prone to leaching in the soil.

For anyone that has yet to apply fertilizer this year – 30-35 units per acre of urea should be spread as soon as possible. With the second application in 4-5 weeks’ time.

Brassica Management

In Spring, brassicas can mature and flower. Do not feed the crop at this stage as most of its nutritive value has depleted and may pose some health risks (crops should be finished grazing by late February).

Milk Replacer vs. Whole Milk

Many farmers are considering using calf milk replacer (CMR) instead of whole milk this year. There are many advantages associated with this:

1. Cost Saving - there is an economic advantage in using milk replacers compared to feeding whole milk that could be otherwise sold for processing (see table).
2. Health benefits - reduced risk of transmission of infections e.g. Johne’s disease when compared to unpasteurised milk.
3. Consistency - reduced risk of scour due to acidification and consistent formulas compared to feeding transitional/whole milk leading to increased calf performance.
4. Flexibility – increased flexibility around feeding time & reduces workload id calves are reared a distance from the parlour.

At present there is a multitude of calf milk replacers available, however, you should be aware of the types of powder on offer. Most milk replacer protein is derived from dairy protein such as skim milk powder and whey protein sources. These ingredients are highly digestible and are the most capable in meeting the calf’s requirements. Some milk replacers will include protein sources from vegetable origins (i.e. soya, wheat gluten and pea protein). However, these proteins have a lower nutritional value and are less digestible than milk proteins for calves under 4 weeks of age.

Most milk replacers have similar vitamin and mineral packages but some offer specific health packages aiding calf health – increased amino acid profiles, antioxidants and prebiotics.

Drinagh stock a wide range of calf milk replacers from the leading brands in the market. Contact your local sales representative or branch for more information.

Cost comparison of milk replacer at 12.5% concentration versus whole milk* over 8 weeks.

*Whole milk price @34c/l = revenue foregone by not selling milk for processing