Utilising high-energy forage crop for out-wintering young stock

This year, Teagasc Green Acres Calf to Beef Programme participant Irvine Allen reared 109 spring-born Holstein Friesian bull calves on his farm in Moate, Co. Westmeath.

Housing is complete with the exception of 81 spring-born calves, which are currently grazing Redstart – a hybrid of forage rape and kale – and will remain on this crop for the winter, before being turned onto grass in February 2021.

This hybrid crop is mainly used as a high-energy protein for out-wintering both cattle and sheep.

Irvine has been growing this crop for the past four years. He has been utilising the benefits of out-wintering young stock on this forage crop – as it aids both rapid growth ability and all-year-round performance.

Sowing method

Irvine identified an 11ac field of old pasture, which was sprayed off on August 1. This pasture was left to die-off for two weeks before tilling occurred, with a light cover of slurry applied during the intermittent period to aid nutritional requirements.

Prior to sowing, the ground was prepared by tilling with two runs of a disk harrow, along with a one pass of a power harrow on August 13.

Through the use of a seed drill, the seed was sown before an application of 10-10-20 was spread on the field at a rate of 3 bags/ac. As there was dying trash remaining on top of the seedbed, one bag to the acre of granulated lime was also applied to aid the germination of the seed.

From having previous experience in re-seeding grass pastures and sowing rape and kale hybrids, Irvine is a firm believer in fertilising the crop as well. He stated:

The tilling and sowing is the expensive part; the yield needs to be maximised in order to make it worthwhile.

To aid this, a final bag of 18-6-12 to the acre was applied to the crop in order to provide that final boost of nutritional supplementation.

Grazing management

The winter management program has been drawn up for the farm and involves Irvine housing 28 of his lighter stock. This is to aid their liveweight performance and reduce the threat of a setback.

Some 81 weanlings, which are split up into three groups in the ratio of 21:30:30, are currently being out-wintered on the forage crop consisting of a rape and kale hybrid.

Each group of calves have been provided with a sheltered 1.5ac grass lie-back, which protects the calves from harsh weather conditions during the winter months. 

Irvine had to be strategic in his management of these young animals on the Redstart crop. If he allowed these weanlings to graze into the forage crop straight away, it may result in some digestive upsets. Therefore, a gradual introduction was commenced over the space of a week to avoid this issue.

In order to meet recommendations on providing sufficient balance to these weanling’s diet, high-quality baled silage (73 DMD) is fed alongside the forage crop. These will now each account for 50% of the animal’s diet.

The baled silage is being fed at a dry matter content of 36%. Assuming each bale weighs 600kg, it can be estimated that there is approximately 216kg of dry matter in each bale provided.

These young animals will have a dry matter appetite which is 2% of its own bodyweight. Therefore, taking into account the average weight of each weanling is 248kg, there is a requirement of 5kg DM/day per animal.

Currently, the weanlings are consuming one bale of silage per day, which calculates to be an average of 2.7kg of dry matter for each of the 81 animals. Essentially, this means that Irvine is on target of having silage accounting for 50% of the total diet.

A re-calculation of these animal’s dry matter requirements will have to be reviewed regularly as their liveweight increases.

Dosing and vaccination programme

As this forage crop contains goitrogens, it can disrupt the production of thyroid hormones by interfering with iodine uptake in the thyroid gland and, in turn, lead to goiter.

To avoid this, all of the calves were supplied with a mineral dose which is high in iodine before they entered the forage crop.

They will continue to receive this mineral dose every four-to-six weeks to avoid an imbalance of iodine and ensure they continue to thrive. A seaweed lick is also made available to each group.

Additionally, all calves were treated with an Ivermectin pour-on and and provided with an IBR vaccination.

Target weights

As previously stated, the average weight of the calves being out-wintered is 248kg – this result was taken from housing weighing conducted on November 4.

While progressing over the 120-day winter period, an average daily liveweight gain (ADG) of 0.6kg is targeted for these animals. This means they should achieve a turnout weight target of 320kg.

Of the 28 lighter calves which were housed, they recorded an average weight of 205kg. These animals are currently receiving 2kg of 14% crude protein concentrate along with high quality (76 DMD) baled silage.

The concentrate feeding to these calves is being front loaded until the early stages of the winter. From then on, they will be reduced to average 1kg/day over the course of the winter period.