Fodder Beet

A cow in the dry period typically requires 10-11% dietary crude protein as a minimum to remain healthy and gain muscle mass as well as body fat. This requirement (for udder development, colostrum production, rapid phase calf growth) starts to rapidly increase in the final 3 weeks of gestation reaching an optimal 16% in the final 10 days before calving. Fodder beet (FB) is usually low to marginal in protein. The leaf yield of the crop is a prime determinant in the total available crude protein. Crops that have low leaf yield or have had minimal nitrogen application/depleted soils will generally be low. Careful consideration needs to me made around the form of supplements to complement a FB diet. Where the CP levels are low, addition of a good quality grass or lucerne silage/bailage will aid in restoring to optimal levels, whereas a poor-quality hay or straw will worsen the situation. Getting crops tested for crude protein is a good place to start when calculating supplement balance.

Fodder beet may be low in Phosphate (but not always) and is commonly low in Calcium. Phosphate levels in beet in the Waitaki area are not as low as those reportedly found in other areas in Canterbury. With Calcium the leaf typically contains 5-7 times the concentration than the bulb. Thus, having a healthy leaf yield is a good way to ensure cows are not deprived. Testing for these two macro-minerals is a good start point to decide on the requirement for supplementation. Lucerne is a good matching supplement for FB as it is generally high in protein and very high in calcium.

Where is it is possible to provide calcium on FB I suggest you do it. 50g/day of DCP plus an additional 50g/day of limeflour will meet most requirements. Some crops are quite low in salt. Mixing salt with limeflour/DCP can encourage intakes. Most Fodder beet ‘loose lick’ type products benefit from an additional calcium boost.

Selenium levels are always very low, so ensure cows are well supplemented while on crop or going on and coming off. High rates of soil ingestion can deplete liver copper stores so keep this in mind particularly with R1s and R2’s.

Kale/Giant Rape

Generally, kale will have adequate crude protein to support pregnancy - ~15% crude protein, but this is not always the case if it has been nitrogen deprived (it can measure sub 10%). Most of our brassicas are high in Calcium so require no additional supplementation – they can be quite good at replenishing bone stores.

Kale however contains goitrogens which can bind up dietary iodine. Consider supplementing with iodine, particularly with R2’s as deficient heifers are more prone to still births.

Kale diets usually result in the body consuming more Selenium and Vitamin E (vitamin E deficiency is also associated with still births and RFMs). For Vitamin E restoration try to get back onto 5kgDM plus of grass 10 plus days before calving and ensure selenium supplementation pre and post going on the crop.

It is recommended that a maximum of 75% of the diet be kale, the rest silage/hay.