Pasture Diversity

FEED CHOICE AND ABILITY TO CHOOSE IS IMPORTANT FOR LIVESTOCK HEALTH

Have you ever watched a group of animals put into a fresh and diverse paddock of pasture – especially one that might have some odd flowering species or ‘weeds’ among the mix?  You will see them eat plants that you might not have expected them to – a ‘weed’ among a beautiful soft pasture or a completely unpalatable looking cotton bush.

Biodiversity of plants creates choice and the ability to choose feeds, which is critical for animals to meet their needs for nutrients and to self-medicate.

This is the third principle of Fred Provenza’s observations of animal behaviour and feeding and it fits so nicely (from the biodiversity point of view), with lots of other things that we know are important for a healthy farm and landscape.

Both in animal and human health we focus on the primary components of food, being energy, protein, nutrients, water, while not strongly considering the secondary compounds or phytochemicals that I have talked about in the last few weeks – like phenols, terpenes and alkaloids.  These phytochemicals also have much to contribute with regard to animal health (and in turn our health as we consume animal products).

Animals will choose a variety of plants to eat from when given the choice.  Here is a great example that highlights the importance of animals’ choice. [private]  There were two groups of cattle offered the same feed ingredients; one group was fed this as a mixed ration, while the other group had the feed components offered individually as free choice.  Feed ingredients included lucerne, corn silage, rolled barley, rolled corn and limestone, as well as a vitamin premix, trace mineral salt and a mineral premix.

The group of animals given free choice made diet selections which compared nutritionally with the total mixed ration.  The rate of weight gain between the groups also did not vary.  What did vary however, was the amount of feed consumed after the first week.  The free choice group consumed less feed than the balanced ration (yet with the same weight gains).  This resulted in a better cost per kilogram of weight gain ($1.58/kg versus $1.36 for the free choice cattle). This suggests that “animals can more efficiently meet their individual needs for macronutrients when offered a choice among dietary ingredients than when constrained to a single diet, even if it is nutritionally balanced”.1

Feed rations are formulated for the average animal in a group, but there are significant differences among a group of animals – “as much as half of the animals in the group may differ significantly from the mean in food preferences and nutrient tolerances”2, yet management practices are often built around the average animal.  Recognition of differences within the herd makes it clear that allowing animals to select from diverse feedtypes will be a good thing for the animals’ performance and health.

What is important to take away from the above experiment is that when free choice in feed is given, offering the diversity that meets the needs of the animal is important.  The flavour feedback systems of animals that I wrote of last week actually rely on the availability of a wide choice of phytochemical rich feeds.   The challenge with this is that current feed availability for our livestock is a reflection of both our production systems and of plant breeding and “farming and plant selection practices have diminished the flavour and phytochemical richness — and hence nutritive value”3.  Studies indicate that “a lack of phytochemical richness in forages can adversely affect the health of livestock and the flavour and nutritive value of meat and milk products for humans.”4 For us humans, there is an extra layer of complexity over our animals, due to the processing of foods.  Human flavour feedback systems are played on by food companies who put flavours that result in positive feedback into our foods, yet they don’t carry the associated phytochemical richness required for satiety and our health.

In the last 12 months we have had a 100% success rate of cattle joined on our farm, during poor seasonal conditions, but while not overstocking.  These cattle had access to all pasture types across our farm.  While we still have a lot to improve and are still working toward better plant diversity in individual paddocks, there is good diversity across the farm and also browsing opportunities from trees and shrubs.  My interpretation of information is that an animal need not satisfy total primary and secondary compound balance in one meal, but if there is a tending deficiency or excess, the animal will correct this with its feeding choices as diversity becomes available in the next paddock.5

A joining rate of 100% is a figure that indicates something going right with regard to animal health.  I think that the secondary benefits of a biodiverse, conscious production system are often not fully considered.  Costs are reduced or eliminated – the cost of infertility of a dry cow, the cost of drenching, the cost of pinkeye treatment, inputs for fodder crops, the cost of pulling calves and the list goes on.

What is our effect on the social environment?

While plant breeding and certain agricultural practices have been good for production quantity, have they been good for long term profitability?  Let’s also consider this in the social context.  I spoke some weeks back about natural capital and the effect to the bottom line when the community cost of detrimentally affecting our natural capital is considered and vice versa (the positive effect of conscious production).  What would be the effect to our bottom line if we considered the positive financial benefits to community health of us producing phytochemically rich, nutrient dense food?  No this doesn’t affect our personal cashflow, but it’s true accountability and does affect the cashflow of the government or health system where we all reside.  It takes a lot for us to consider this degree of accountability as food producers, but I reckon that’s what sets all of us apart as conscious farmers. Only once we accept this, can we appreciate the enormity of our responsibility as food producers, but also the tremendous opportunity that this presents.

 

References 

1. S.B. Atwood, et al. (2001)  Influence of free-choice vs mixed-ration diets on food intake and performance of fattening calves. Journal of Animal Science 2001, 79:3034-3040  23rd April 2015 http://www.researchgate.net/publication/11548868_Influence_of_free-choice_vs_mixed-ration_diets_on_food_intake_and_performance_of_fattening_calves

2, 3, 4, & 5.Provenza, F.D., M. Meuret, and P. Gregorini. 2015. What humans can learn from herbivores about nourishing links between palates and landscapes. Appetite, submitted.

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