The Dry Cow – the most important animal on the farm
Many a lactation is won or lost in the dry cow phase. There has been a significant failure in Australian dry cow nutrition with a tell-tale legacy in national average milk production and fertility. We have one client with rumination technology monitoring cows. Apart from very early detection of health issues in lactating cows, the greatest shock to my client was dry cow rumination; or more accurately put, lack of it! Rumination is the engine of the cow. Any reduction in rumination not just lowers milk production, but the cow is heading downhill very rapidly. Health plummets. But as above, alerts to very early intervention to compensate.
The first and foremost considerations are: energy, fibre and protein; but even more so, dry matter intake (DMI). The above rumination technology alerted us to just how frequently we fail our dry cows with insufficient feed. Using dry cows to clean up paddocks in late summer is a recipe for disaster on intake alone, without any consideration to adequate energy or protein. I defy anyone who can judge how much “consumable” feed is in any given paddock. The negative effects of this in past experience for either dry cows or lactating cows is well documented in our ration analysis library of the past fifteen years.
Dealing with DMI first: we need to feed 8 to 12 kgs DM daily for a dry cow (dependant on live-weight – Jersey/Holstein). Any of my clients who feed solely ad-lib silage to dry cows (we can control the diet for many other parameters when we lot feed drys/springers) can vouch for just how much feed this is: 2 to 3 rolls of silage/cow for a 60 day dry/springer period. Dry Matter intake is number one failure in dry cow nutrition (and springers). It is always either not enough, or too much. Not enough in late summer/dry pastures or hay, and too much in unrestricted, fast fermenting, pasture during the growing season.
The ‘not enough’, apart from sub-optimal rumination/health issues, invariably these dry cows will be very deficient in energy and protein initiating mobilisation of body reserves. We have blood tested dry cows that had no ‘visible’ BCS change, yet were in significant sub-clinical ketosis resulting in LDA’s post-calving (and I might add, low blood calcium = sub-clinical milk fever and still dry!).
Alternately, the dry cow on an out-block with unrestricted lush grass will eat too much (lower fibre/fast fermentation and its inherent problems – acidosis) furnishing excess energy metabolised to body fat and predisposing our cow to ketosis at, or soon after calving, and calving difficulties. On unrestricted pasture her intake of soluble protein will cause very high blood urea nitrogen levels and another whole range of health issues (for later discussion).
Following on from the “too much’, this diet is also too low in fibre. A high fibre diet for dry cows is essential to rumen health/function. We want to keep that rumen churning and producing as many as possible cuds for chewing; qualify this by knowing we are getting our 8 to 12 kg DMI. Hay or dry paddock feed may keep cows chewing all day, but the limited amount of energy/protein digested from poor feeds will plummet her into weight loss and a cascade of health/production problems at calving. Calving, and the ensuing three weeks of health/production data is a potent report card on dry cow/springer nutrition.
Energy: we need an energy density of 9 MJME/kg DM. We are only aiming to meet the cows energy requirement for maintenance (no weight gain or loss), and supply the calf’s needs. For an average 10 kg DM intake, this is 90 MJME; around 70 MJME for cow maintenance and 20 MJME for the calf. The calf’s additional energy needs in the three weeks prior to birth will be met by the three kgs of Lead Feed grain.
Protein: aim for a ration of 14% crude protein. Grazing of fresh pasture will exceed this very significantly, and worse, most of it will be soluble protein causing other health problems as mentioned above. If you haven’t already guessed; there is one feed that ‘fills the bill’ perfectly: silage!
Recent knowledge has raised other matters in the protein arena, what are known as Amino Acids – types or fractions of true protein. Again, a subject for a whole article at a later date, but suffice to say, one of my sons and I are traveling to the USA in February for training in Amino Acid optimisation. More on our return and perhaps some practice on grazing based rations. The potential of balancing amino acids has been well demonstrated in one of our client’s herds: high milk production, high MP%’s and very high fertility.
Last, but by far not least, is mineral nutrition. Supplementation of a sound mineral mix to dry cows is well supported by a burgeoning body of research. The difficulty for us in grazing systems is; how do you do it unless you are fortifying a low nutrient forage source (hay/dry pasture) with a quality dairy grain mix daily? We have designed and manufacture a self-feed, rain resistant mineral mix that can be placed in troughs weekly at dry cow sites.
The dry period is a good opportunity to replenish minerals depleted during lactation even with good supplementation during lactation. Blood tests we’ve done on dry cows have proven the deficiency despite supplementation during lactation. While dry and no lactation demand, minerals reserves can be lifted significantly with whole-of-lactation benefits. Macro minerals of calcium (especially), magnesium, phosphorous are reabsorbed into skeletal frame ready for supplementing milk production and reproduction of early lactation. Likewise, trace elements of zinc, copper, cobalt, manganese and selenium (essential to address retained placenta/foetal membrane), vitamins of A, D3 & E are fat soluble, stored in body fat for, again, supplementing cow health requirements (immunity) in early lactation when demand exceeds intake.
John Lyne is a dairy production specialist with Dairytech Nutrition
www.dairytechnutrition.com.au
