Summer Grazing – its not easy!
10th June 2012

By Dr Hazel Gilmore Ruminant Nutritionist Fane Valley Feeds

The turnout of dairy cows to grass has been difficult this year mainly due to weather conditions and poor grass growth rates.

The majority of dairy herds that are at grass, are operating a part-time grazing system whereby cows are housed and buffer fed at night, something that has become much more common in recent years and particularly in higher yielding herds.

While spring and early summer grass has the potential to achieve maintenance plus 25 litres, this is rarely achieved because there are so many variables affecting grass quality and dry matter intakes. Some sources predict grass dry matter intakes of over 18 kg per day but even in particularly well managed systems, this level of intake is seldom realised and is even more unrealistic in poor weather. The challenge is to balance herd requirements and grass availability – ensuring optimum use of grass but also encouraging optimum output from the cow.

The key factor affecting milk production regardless of system is dry matter intake and the flexibility offered by a part-time grazing system can be the key to maintaining productivity. Perhaps the greatest advantage of part-time grazing is that in periods of grass shortage or poor weather where grass intakes are reduced, the silage and concentrate proportion of the diet can easily be increased to allow for this change in dry matter intake. Similarly, when grass quality is reduced, the overall specifics of the diet can be maintained by altering the indoor ration. This is traditionally more common in the later part of the grazing season. Maintaining a silage plus concentrate element to the overall diet is also useful at the turn out and housing stages of the season, cows dislike change, and the provision of silage and concentrate helps to offset any negative effects associated with transition from an indoor diet to a grazed grass diet and vice versa. Providing silage plus concentrate throughout the summer months also helps to reduce the drop in milk butterfat content associated with grazing diets – providing the long structural fibre required to optimise rumen function.

A further benefit of the part-time grazing system is the ability to meet the demands of freshly calved and cows that are not yet in calf. While some would argue that the inclusion of silage in true grazing systems will reduce grazed grass intakes and therefore compromise efficiency the requirements of high yielding dairy cows are difficult to meet in a low input, grazing system. These cows will produce milk at the expense of body condition as a result of excess dietary protein and a shortage of energy- with negative effects on fertility and milk quality.

An increasing number of herds are keeping high yielding dairy cows housed all or most of the year. Some farmers, with the ability to group cows according to stage of lactation or yield, will graze lower yielding, stale cows or cows that have been confirmed in calf while keeping the remainder of the herd indoors. This is perhaps one of the best options available in terms of meeting the requirements of specific groups of cows, however you must consider the implications - keeping cows indoors will increase feed costs and require extra slurry storage. It may impact on other areas of your business- such as labour requirement and overheads. In the current climate where milk price has declined and feed costs increased, particular attention must be focused on both production costs and factors that can affect overall profitability such as infertility, milk quality and cow health. While each of the systems mentioned have advantages and disadvantages, the system you chose must meet your own farm and herds requirements.

Whatever system you operate this summer, Fane Valley Feeds can meet your requirements with a high quality range of summer grazing and indoor dairy rations– getting you more milk and better performance this summer. For more information please contact your local Fane Valley Feeds Sales Representative.