There are three aspects associated with dairy farming that can elevate or decimate farm profits and individual cows — feed, fertility and lameness.
All three are highly related, outside environmental causes to lameness.
As obvious as it may seem, feed and fertility are well research-proven limitations to farm profit.
Based on the Australian 305-day lactation average milk production, clearly we are underfeeding our cows by at least 4kg dry matter daily.
We have bred cows through genetic advancement that have far greater capacity for converting feed dollars to milk dollars, yet we have not taken advantage of our investment in genetics when our national average milk production is half that of the United States
Cows are cows and feed is feed, irrespective of delivery system — grazed or TMR (total mixed ration).
Producing more milk from the same fixed costs, increases our competitiveness, but more so, our profit.
Having the feed to optimise our cows’ capacity for converting it to milk dollars is a multi-faceted issue.
Suffice to say, number one is allowing cows access to feed per se. From there we look to planning the growing of forages that are highly digestible.
We can fill a cow to contentment with hay, but she will not convert that hay to much milk.
Worse still, the conversion of hay dollars to milk dollars is not profitable due mostly to very slow digestibility rates that limit daily DM intakes.
From here we look at energy and protein densities.
How much energy and protein is in each kilogram of dry matter consumed by our cow?
She has a physical limit to DM feed intake, so the higher the energy and protein in each kg DM of feed, the higher the total energy/protein intake will be, and obviously, how much milk she will produce daily.
We run a ratio in our diet analysis program of energy to maintenance and production.
This ratio is critical in determining feed cost per litre of milk produced.
Further, as this ratio shifts according to feed intake, digestibility and energy density, the cost of producing a litre of milk rises or falls rapidly.
There is a multiplier effect occurring in the shifts of this ratio; for better or worse.
Feed intake, digestibility and energy/protein density are the macros of dairy nutrition and production.
However, the next plane is mineral nutrition.
Our forages are a mixed bag of minerals, some excessive and some deficient.
For example, our forages tend to be between excessive and highly excessive in potassium fertiliser dependent.
Our cows have a massive requirement for calcium, and pastures are very low in calcium; likewise, magnesium.
It is essential we supplement our cows to regulate excesses and supply deficiencies.
Cows also have a high salt requirement.
Next we need to consider trace minerals. Although they are supplemented in very small amounts, they are highly essential to many biological functions of dairy cows.
Trace minerals are not very bio-available from plant tissue, and must be supplemented via mineral pre-mixes in grain.
The critical roles of commonly supplemented trace minerals and vitamins are:
■Copper, manganese and zinc play important roles in protein synthesis, vitamin metabolism, the growth of ligaments and immune function.
■Cobalt is essential to B12 vitamin production in the rumen, and if not limited, will supply all the cow’s need for B12.
■Vitamins A and D are commonly supplemented despite their natural availability from green forages and sunlight respectively, to ensure no compromised requirement.
There are two other essential supplements that I have left until we look at fertility, as they are critical to that major profit driver.
They are the trace mineral selenium and vitamin E.
Both have vital roles in uterine health, therefore fertility.
Further, both are antioxidants that have important roles in stabilising fatty acids and soluble vitamins. Their role in reducing toxicity of fats is very significant in our grazing-based system as pasture has very high fat.
Fertility then becomes a natural and serendipitous outcome of a fresh cow that has not suffered excessive negative energy balance from underfeeding, or pre-calving nutrition, has her mineral and vitamin requirements met, and then, a healthy and vital uterus.
The one issue that can decimate all the above is lameness.
Lameness prevention has specific nutritional needs, all of which are mentioned above related to milk production and fertility.
However, to highlight a few very necessary preventative measures, we ensure adequate zinc is fed for formation of sound hoof material.
Limit weight loss post-calving which can reduce the fat pad and its shock-absorber function in the heel, and of course, feed buffering agents and adequate effective fibre for good rumen health and mitigation of sub-optimal ruminal pH (SARA).
Supplementing Biotin in mineral mixes added to grain has significant benefits to hoof integrity.
Addressing environmental causes to lameness such as track maintenance, minimising sharp turns on concrete or covering with rubber mats will reduce injury and wear to hooves.
Applying zinc sulphate and copper sulphate solutions alternately via absorbent mats while exiting dairies are beneficial in drying and hardening soles during wet conditions, reducing risk of stone punctures and bruising.
Despite our best efforts in all the above, I cannot stress enough that failed transition nutrition will severely reduce our ability to enhance our cows’ capacity for profitable lactations through feed, fertility and the absence of lameness.
dairy production specialist