Transition cow management – thinking beyond DCAD

Pip Gale
Head of Nutrition and Technical Services

Growing up on a dairy farm in the far north-west corner of Tasmania in the 1980s, I always looked forward to calving season. Sure, it was a hectic period with a heightened work load and seemingly no end of sleep deprivation, but I always found bringing our herd of cows successfully through transition with a new group of replacement heifers on the ground incredibly rewarding and satisfying. Plus, there was a sense of excitement about the future prospects! In those days, it was considered ‘forward thinking’ that we included magnesium oxide in the small square bales of hay that we fed to our ‘springers’. How times have changed for the better!

Over the past 20 years, most dairy producers have become quite familiar with the need to provide unique rations during the pre-calving period in order to reduce the incidence of clinical and sub-clinical milk fever. Unique ration balancing concepts are discussed, such as Dietary Cation Anion Difference (DCAD) to slightly acidify blood, high levels of magnesium to stimulate parathyroid hormone (PTH) along with an eye to manage potassium to magnesium ratios are just beginning to scratch the surface of TCM ration management.

It is well accepted that the correct application of these key principles will result in the decreased incidence of clinical and sub-clinical milk fever and the plethora of metabolic diseases that are associated with them. We are firmly entrenched in always delivering these basic principles, remembering that the ‘golden rule’ of transition management is to always be supportive of DMI. But are there other areas of interest that we should also begin to focus on in order to bring continuous improvements to our cows during the transition period that will further underpin the social, environmental and financial sustainability of our dairy businesses?

The transition period is best defined as the four weeks prior to, and immediately following calving. It is an absolutely critical time for every farmer, cow and dairy business, with studies showing that up to 80% of total annual disease costs occur during transition, along with it being the peak period for deaths and involuntary culling.¹

Successful transition sets the foundation for a successful lactation, which can be described by the following:

-A healthy, live calf is delivered via a non-traumatic birthing process

-Cows do not suffer ill-health or excessive body condition losses post-calving

-Cows steadily increase DMI and production to achieve peak milk solids targets within 45 days

-Cows exhibit functional immune status to deal with inflammation whilst conserving energy

-Cows are fertile and cycling before the start of mating, supporting improved 6WICR’s.

While much of the pre-calving ration is focused on successfully navigating the final few weeks of pregnancy, the birth of a calf must be seen as the beginning rather than the end of the transition period. Given that cows are the actual champions of a dairy business, bringing together best management and nutrition practices to support their health and rapidly changing nutrient requirements is of paramount importance. Below is a list of key issues that must be addressed during transition in order to establish a successful lactation:

Challenge: Dry Matter Intake

Challenge: Blood Calcium Status

Challenge: Body Condition Score Loss

Challenge: Immune Function

Challenge: Reproduction

As a practical starting point, one of the keys to success during the pre-calving period is ensuring that the feed is offered for the correct number of days before calving, relative to the feed formulation. Optimum time spent on pre-calving rations for milk fever control is determined primarily by calcium levels (min. 21 days for low Ca, low DCAD products, max. 12 days for high Ca + Hy-D^®). In one study, optimum increases in milk volume, milk fat and milk protein were seen at 24 days of exposure to traditional low Ca, low DCAD feeds pre-calving. Although no further production gains were associated with longer exposure (out to 49 days), no detrimental effects were noticed.² Another study found significant reproductive benefits were associated with exposure to balanced TCM rations for more than 20 days pre-calving, and fewer cows were culled or died during the subsequent lactation.³

If you are providing a pre-calving ration that is heavily based on cereal hay and/or straw, you may struggle to meet the basic energy and metabolisable protein requirements of heavily-pregnant cows. Avoid legume-based rations (e.g. lupins or lucerne) due to their high potassium content. High quality maize and whole crop silages have a place, as does a small amount of grazed pasture (about 2 kg DM). Published studies have shown that inadequate MP pre-calving can result in significantly reduced milk protein yields in early lactation.⁴ Aim to provide at least 1.2 kg MP per cow as a minimum target (equivalent to about 15% CP). It goes without saying that you will have sent samples of all the feeds you will offer during transition for wet chemistry analysis to establish their DCAD levels.

It is just as imperative to provide your cows a positive DCAD, high calcium ration immediately after calving as it is to provide a negative DCAD, low calcium ration pre-calving. The anionic ingredients – magnesium chloride and sulphate, ammonium chloride and sulphate, calcium chloride etc. – are replaced with fine limestone, DCP, magnesium oxide, salt, sodium bicarbonate, Acid Buf^® etc. to meet the rapidly-increasing calcium demand associated with colostrogenesis and lactogenesis. We are moving from transferring stored calcium from bone to blood with a negative DCAD to now absorbing calcium via intestinal pathways to support ionised blood calcium levels. Offer the best quality forages with high NDF digestibility in combination with maize, canola meal and wheat based concentrates to support DMI.

CopRice can help you address the complex issue of transition management. CopRice PreCalving, PreCalving + Hy-D^® and PreCalving + BioChlor^® pellets incorporate modern feed ingredients to optimise the health and productivity of your herd pre-calving, while Lac Cycle Fresh Cow pellets are specifically formulated to take care of business post-calving.

Your local CopRice TSM can help you to create a TCM ration plan and feed budget tailored to your feed base and the specific requirements of your herd. Contact your local CopRice advisor or contact us here.

Pip Gale is recognised as an industry leader. Following a successful and recognised career in dairy business management, he has spent the past 20 years providing nutrition and farm consultancy services throughout Australia and New Zealand. President of the Australian Associationof Ruminant Nutrition (AARN), Pip is passionate about maximising the efficiency, profitability and sustainability of dairy farmers.

References: 1. Ribeiro et al. (2016) Carryover effect of postpartum inflammatory diseases on developmental biology and fertility in lactating dairy cows. J. Dairy Sci. 99:2201-2220. 2. DeGaris et al. (2008) Effects of increasing days of exposure to pre-partum transition diets on milk production and milk composition in dairy cows. Aus Vet. J. 86:341-351. 3. DeGaris et al. (2010) Effects of increasing days of exposure to pre-partum transition diets on reproduction and health in dairy cows. Aus Vet J. 88:84-92. 4. Van Saun et al. J. Dairy Sci. 1993.