Beef: Zero grazing has come a long way since the 1980s
Published 09/12/2015 | 02:30
The winter weather is now firmly upon us, with heavy rainfall and dropping temperatures throughout the country. For that reason, the topic of grazing and in particular zero grazing could not be further from most people's mind.
Last week I carried out a review of 2015 with a beef finishing client in county Cavan. This review normally entails a review of animal purchase weights, ration costs, health programme, animal performance and carcase assessment. This year it included a new section, as it was the farms first full season using the zero grazing system.
Much has been written and talked about this system with the recent surge in machinery available to carry out this task. I first encountered zero grazing over 30 years ago. Back then, using an old 'double chop' harvester to cut grass that was almost fit for silage and packing single axle trailers with lots of wet grass was my flirtation with the system.
The grass tended to heat significantly and harvesting had to be stalled during any adverse weather conditions due to the inadequacies of the machinery. I encountered the need to supplement the animals with high rates of concentrates as a result of variable grass quality. Grass regrowth was also impaired due to the harvesting process and there was a poor utilisation of slurry. For all those reasons, the system was chalked off as a 'been there, done that' experience with a return to full grazing the following season.
Nowadays, the zero grazing system appears to divide opinion within the farming community in a similar manner to debates about the best make of tractor, robotic milking or the growing of maize under plastic.
I sometimes viewed anecdotal stories of massive grass output, huge grass intakes and excellent daily live weight gains with scepticism as farmers trying to justify the system to their peers (and themselves!). However, if all zero grazing systems were to be practiced as I witnessed throughout the year on this Cavan beef farm, then the system could be considered seriously on many farms throughout the country.
In complete contrast with my experience of the system in the early 80's, the machinery is now well designed and purpose built for cutting, hauling and dispensing the grass. The cutting/ chopping systems don't over process the grass thus reducing the risk of rapid fermentation or heating.
The farm housed 90 continental cross heifers during the summer months. They were housed at an average live weight of 475kg. The capacity of the machine (4.5 tonnes of fresh grass) was sufficient to supply the 90 heifers for one day. They were supplemented with 2kg/head of high energy concentrate plus minerals.
During the summer, we calculated that the heifers were consuming 10kg of grass dry matter plus 1.75kg of concentrate dry matter per day. This grass was consumed in a significantly shorter space than would be the case at pasture, meaning longer time was spent lying, ruminating and putting on weight. Phenomenal live weight gains of 1.8kg/head/ day on these U grade type heifers was achieved.
Careful management meant the sward height was always cut between 14-18cm or the equivalent of 3500kg/DM/ha. Harvest rotation was every five weeks with one bag of Cut Sward applied per acre after each cut when slurry wasn't used.
An equivalent group of heifers were conventionally grazed during the summer. The farmers opinion was that these heifers had a very stop-start season until September and they only started to thrive during the good back end. These heifers are now housed and are approaching the halfway point in their 100 day finishing period. The vast majority of the zero grazed heifers have now been slaughtered with carcase finish and quality being exceptional.
There is no disputing the fact that the zero grazing system requires increased labour input, it took 1 hour 10 minutes to complete grass collection and feeding on a daily basis. The initial capital investment of up to €30,000 is another obvious impediment to the system.
On marginal ground, the grass harvesting season can be longer than the grass grazing season, with better slurry utilisation being another major benefit. The increased animal performance can simply be attributed to the higher intake of quality grass, which is not always possible with conventional grazing. While the system has shown great results on this farm, I would love to see it scientifically researched in the near future.
Gerry Giggins is an animal nutritionist based in Co Louth