Animal Nutrition

Nutrition is one of the most critical elements in farming today. Farmers using improved genetics require better nutrition to achieve the full genetic potential in milk yield or growth potential. Nutritional inputs are becoming more expensive. Ensuring efficient rumen function to utilise feed inputs fully is a prerequisite to make dairy or meat farming a profitable enterprise.

Ruminants eat grass, but grass is very indigestible and more often than not very poor quality as a food. The main structural carbohydrates such as cellulose and hemicellulose are not easy for normal gut enzymes to digest. In order to get enough nutrients from such a poor source a part of the ruminant gut evolved into a bag where microbes could live and digest this structural carbohydrate. This place is the rumen for cows, sheep and goats. In this bag the microbial population grows on the poor quality grass, releasing volatile fatty acids as a byproduct of their growth. These VFAs are absorbed as energy by the cow. The VFA’s can provide up to 80 percent of the energy needs of the animal. In addition the microbes themselves are easily digestible by the cow, so as they are washed out of the rumen they are themselves digested and provide much of the protein needs of the cow. Microbial protein is high-quality protein because it has a good balance of the essential amino acids needed by the cow. Microbial protein contributes a large portion of protein for the ruminant animal to digest in the small intestine. As much as 1.4 to 1.6 kg of microbial protein can be synthesized per day in the rumen of a mature Holstein dairy cow. With a high protein forage such as alfalfa this should be able to support 15-18 litres of production per day. Whilst not a significant production level in the context of large UK or US dairies, this is far in excess of most sub-Saharan smallholder farmers. We know that we can significantly change the production levels of cows in these systems by changing the farmers’ understanding of the importance of forage in the cow’s diet and that if we can learn to feed the rumen properly then we can begin to feed these cows properly.

Understanding and manipulating this process is a key objective for any dairy farmer. The forage component of the diet is by far the most important part of the diet of a cow. Perhaps because for us grass is such a poor quality food we as farmers cannot relate to how much goodness a cow can derive from such material. We therefore feel that in order to perform, a cow must be given a much higher quality, supplementary compound feed and we forget about how critical fodder is. We then feed what we can gather as fodder - often overgrown, lignified napier or maize stover or wheat or grass straws whose goodness has already been harvested by us as seeds, wondering why the expensive compound feed is not improving production. A further problem of feeding increasing amounts of compound feed is that the microbe population changes and the rumen becomes more acidic to deal with the starches and sugars and we encourage acidosis in the animal with increasingly negative effects.

We therefore need to ensure that we return to ruminant feeding basics. The base of the “feeding pyramid” is mainly concerned with fodder. We need to ensure good quality fodder before we add anything else. Better quality fodder has higher levels of cellulose to lignin (wood), higher levels of protein and simple sugars. It is also the perfect food for the microbes in the rumen. Too often the cow is fed poor quality fodder and high quality compound feed. Compound feed may be necessary to support higher levels of production but it will only show real impact with a well functioning rumen producing the bulk of the energy and protein needs of the cow. Compound feed on its own will not be able to compensate for a poorly fed rumen.

High quality fodder is therefore the farmer’s objective. Whilst maize stover may be available it is a very lignified and woody stem that actually reduces feed intake and will therefore be detrimental to production. Preferred fodder should be naturally grazed pasture, young napier harvested at around 1m high or good quality silage and hay or baled alfalfa (lucerne).

A key element in our understanding of fodder feeding is that as fodder becomes older and more fibrous it has a negative impact on feeding rates. Animals forced to eat such poor quality fodder will become full quicker and therefore their intake of feed will never be at the level necessary to sustain modern production. Such material reduces feed intake but is also not ideal for the rumen microbes so not only are we encouraging lower intakes we are also reducing rumen function. To combat this we need to feed better quality, less lignified material to keep feed intakes high and ensure good rumen function generates the all important volatile fatty acids and proteins for the cow to digest and absorb.

Another key element is that the rumen microbe population is a dynamic collection of different species of protozoa, fungi, yeasts and bacteria. This population changes depending upon what is being fed and changes to microbial populations lag behind the physical changes we make in diet. This means that a change of diet may not suit the particular collection of microbes in the rumen and they have to come to a new equilibrium based on what they are now being fed. This means that rumen function dips momentarily and takes a bit of time to settle into a new equilibrium. If we keep making changes to diet the microbial population never settles and once again rumen function is reduced. It is therefore important to try to keep the fodder portion of the diet as stable as possible day after day, week after week and year after year.

Once we have a well functioning rumen that is being fed good quality fodder every day we can now think about boosting the naturally produced rumen-derived energy and protein with a good quality compound feed. We can also supply the trace minerals that the animal may require at the same time. The correct balance of trace minerals must be presented to rumen bacteria as well as minerals being made available to the cow for homeostasis, milk production, muscle development and other life functions such as skin and bone formation. In all cases we must always remember that the bulk of the nutrients satisfying the requirements of our animals is coming from rumen function and that the rumen needs a stable diet of good quality fodder to perform properly.

Livestock need minerals to grow and utilise their diet. In ruminants minerals need to be supplemented in the diet as forages and grain are a very poor sources of minerals. Without a sufficient micronutrient supply to the rumen the microbial population living in it will not function correctly. If the animal is deficient in one or more minerals, it is very likely that the microbial population is also deficient. A deficiency will decrease microbial growth, reducing the population in the rumen and decrease the digestibility of the diet. Minerals are essential for immune function. Calves and heifers require minerals to build lean tissue and bone. Lactating animals are continually losing minerals through milk, which need to be replaced. Dry cow physiology is significantly impacted by the mineral balance of her diet and her productivity as a lactating cow depends upon proper mineral management during the dry period.

Forages also reflect the mineral composition of the soils they are grown in. Vital Animal Health has ensured that our formulations compliment this. For instance East African forages are often deficient in copper and cobalt and very high in iron. The iron exacerbates the copper deficiency because iron binds to copper and makes it biologically unavailable. Typical copper deficiency symptoms such as the gingering of a black hair coat are commonly seen in the field and can be easily addressed by a good quality mineral supplement. All Vital mineral formulations apart from Vital Kondoo contain at least three different sources of copper to combat the problem of copper lock-up and it is also for this reason that none of the Vital minerals contain any intentionally added iron or molybdenum.

It is also important to attend to changing physiological needs during the life stages of a cow. We have developed formulations that accommodate these very different needs. It is becoming more recognised that poor mineral nutrition is a major cause of poor performance in cows. Vital Ndama is a formulation for calves and young stock; this in turn is replaced in heifers by Vital Joto for good heat detection (bullying) and conception. Vital Dry is specially formulated for the requirements in the later stages of pregnancy. Once calving has occurred the production of milk again places different demands on the system of the cow and Vital Maziwa has been formulated to meet these needs. For beef animals Vital Nyama has been specially formulated to meet the needs of the indigenous cattle grazing on Kenyan pastures and Vital Kondoo has been developed for supplementation in sheep and goats. Vital Ngamia has been formulated to meet the needs of a lactating camel and also support growth at lower doses in camel calves. Vital Farasi has been formulated to meet the mineral needs of horses. In most cases additional mineral top-up is provided by the presentation of the Vitalblock.