Advantages of blood testing
Properly pre-planned blood sampling will identify any constraint much more quickly and cost effectively than awaiting performance effects.
The Dairy Herd Health and Productivity Service (DHHPS) programme operates on the principle that the cows' opinion, expressed through its blood biochemistry, is the most accurate and the quickest way of assessing the effectiveness of a diet. Even with the most modern rationing programmes and forage analysis, diets sometimes do not work as anticipated.
Careful monitoring of weight and condition score change, milk yield, milk quality, heat signs and conception rates may, with time, indicate that there is a constraint.
Earliest indication of effects of new diet
Blood sampling under DHHPS rules shows what the cows think of the diet two weeks after it has been introduced - usually before any shortcomings have had an economic effect.
The results also show what those shortcomings are and therefore allow alterations to be based on information rather than guesses. Rationing, based on forage analysis and on assumptions of actual food intakes, is not very precise.
Most farmers, having set a ration, have to look out for signs of its failure before they know if adjustments are necessary.
Gross errors should be immediately obvious, but otherwise farmers are dependent on bulk tank returns, monitoring lactation curves, condition and weight change, the strength of heat signs, conception rates, milk quality and dung consistency.
By the time any of these are noticeably astray, at least six to eight weeks may have passed, with inevitable economic loss. Even then, although it may be clear that something is wrong, it will not be apparent what it is, and therefore what specifically needs doing to the ration.
Energy levels in diet are the most important controlling factor on performance in cattle and sheep. Deficiencies and excesses influence milk yield, quality, health and fertility. Blood sampling will show the presence of energy problems at the most critical times - late pregnancy in cattle and sheep and early lactation in cattle.
Economic forage utilisation
Blood sampling can show the level of energy available from forage - grass or silage - within the herd and thus allow economic adjustments of concentrate inputs.
Effective rumen degradable protein
Shortages of ERDP are not detectable by any means other than blood/milk sampling. When they occur, it is often under unexpected circumstances, e.g .on occasion when feeding theoretically excellent silage.
Cows, then, just do not perform to expectation. The increased use of maize silage and whole crop cereal silage, both potentially low in ERDP, makes this measure very useful in checking rationing.
Digestible undegradable protein
Circumstances when extra DUP is likely to be beneficial and, on the contrary, when it is likely to cause problems, can be identified. Current computer-based theory is not totally reliable, probably because of shortcomings in silage analysis.
Cows have a requirement for a daily input of magnesium, as they cannot draw on reserves to any great extent.
Whether it is being achieved can only be checked by blood sampling, increasing the chances of preventing staggers and milk fever and controlling marginal magnesium deficiency which affects appetite and productivity.
The DHHPS programme provides help for increasing or maintaining milk yield per lactation, milk yield per cow per year and milk quality. It helps control:
- milk fever
- retained placenta
- stillbirth/calf viability
- displaced abomasum
The suckler cow programme primarily allows increases in fertility, and control of staggers and increased calf viability are further potential benefits.
The flock health and productivity programmes reduce twin lamb disease, increase lamb birth weight and viability and allow economic control of concentrate usage.
Communication with your vet
The framework of the DHHPS programme ensures full communication between farmer and vet. Otherwise, this does not always take place which means that positive measures for prevention and control may never get started.
With members all over the country, the DHHPS programme acquires and makes available topical and seasonal information to dairy farmers involved.