Today’s Cow

Today’s cows have genetic drive to produce milk at all costs

An analogy I like to use to highlight this issue is: grandpa used power kero to fuel his 35 Fergie. Why don’t we run our ‘genetically improved’ 200 hp Fendt on power kero? (Forget the AdBlue). The answer every dairy farmer knows. So why do we fuel our ‘Fendt genetic’ cows on 1950’s diets expecting ‘Fendt’ performance? Grandpa had very few fresh cow problems. But grandpa was on a roll at 10 lts from fresh cows. Back to the 35 Fergie/Fendt analogy and the fuel.

Mike Hutjens, dairy professor extraordinaire, has a favourite saying; “Dry matter intake (DMI) solves a lot of problems”. This applies across the board; fresh cow, joining cow, lactating cow and dry cow. And all from the same problem, Negative Energy Balance (NEB). When cows are mobilising body fat we get a cascade of metabolic problems, in both dry and fresh cows.

This article however, is interested in DMI pre and post calving. There is very scant evidence that milk production per se contributes to greater disease incidence at or around calving. Grandpa’s transition management consisted of putting dry cows in the back paddock and checking once a week to if any had calved, or died! I vividly recall trying to outrun week old calves. The evidence is in the pending knee and hip replacements.

In our ‘Fendt’ age transition, we measure dry matter intake by strip grazing pasture and offering hay/silage adlib and recording hay/silage consumption. By this method we can measure energy, fibre and protein intakes and adjust strip fence size accordingly. Oh, and we do this daily, not weekly. The goal with dry cows is they dry off in calving BCS and do not gain or lose weight pre-calving. Either will precipitate calving problems, NEB especially, which invites all other issues.

To quote the science, cows that mobilise body fat, or increase it, through this period will experience lower dry matter intake before and after calving inducing NEB, disease from impaired immune function (mastitis, metritis etc), increase indicators of inflammation in blood reducing fertility as well as other cell damage from oxidative stress.

I personally, am not a fan of BCS scoring as it always seems like shutting the gate after the horse has bolted. Managing the diet to prevent this is far more proactive, and less costly. I have written previously of the immense fertility gains from managing calcium and protein intake through the dry cow (and springer) phase, but general mineral nutrition is equally important at this time too. We use self-feed minerals for this purpose.

As we move closer to calving, the twenty one days of springer cow management, we have an excellent tool to assist in getting blood calcium levels right. Monitoring urine pH. This will mitigate the vast majority of our calving, and post-calving problems when coupled with rising dry matter intake post calving for a cow that has no clinical or sub-clinical milk fever. Our management of urine pH can determine the cow’s future. There is no happy plateau here. It is a rapid spiral; either up or down! She is going to be highly productive and fertile, or a sixty day cull statistic (or worse, a carry-over).

Milk fever, clinical or sub-clinical, has a Siamese twin called ketosis, clinical or sub-clinical, and they go everywhere together. Fortunately, we have another wonderful tool for managing ketosis as well. Milk keto test strips. Simply strip milk onto the keto test strip on day three post-calving and drench with propylene glycol if she registers any BHBA reading on the strip.

We have a number of clients by virtue of their computerised rotary dairies, that simply feed 25 ml of propylene glycol on top of their bale feed for 20 days. All done automatically and discontinued automatically as the fresh cow passes the twenty day threshold on the computer.

A brutal measure of transition efficiency/success is the sixty day cull rate. The goal should be less than 5% fresh cows leaving the herd before sixty days-in-milk, and less than 3% deaths in this same category, a total of 8% exits by chopper truck or knackery truck.

Back to our dry cow. She is capable, even in a low energy diet, of consuming 40% to 80% more energy than required, although, grandpa’s back paddock transition management in drier times of the year, the reverse was usually true. The variations in energy intake through differing seasons are massive. As above, both beckon calving problems. High fibre diets that meet energy and protein requirements are the goal. Dry cow rumen regeneration thrives on high fibre diets.

With all our advances in dairy science and analytical assays, we still cannot pass up grandpa’s ‘acid test’ of diet and cow’s health; the age-old husbandry skill of observing manure. The test offers instant feedback. Manure is the window of the rumen. It does not tell us much about NEB, sub-clinical milk fever or ketosis, but we have those covered, but it certainly tells us when rumen function has gone awry. Any dysfunction of the digestive tract will derail our best efforts in all other transition management activities.

Those ‘Fendt genetic’ cows will milk themselves to death if we do not manage their needs. Grandpa’s cows just dried themselves off when he failed to meet their needs.

John Lyne is a dairy production specialist with Dairytech Nutrition

www.dairytechnutrition.com.au

Only One Chance (Growing Out Heifers)

 

Adequate nutrition of growing heifers can be a challenge over summer months when ample quality pasture is not available. Frequently low protein diets through this period can limit frame and muscle growth rates. Well grown heifers that conceive on time can go on to be highly productive dairy cows; but if they do not meet these criteria it is a lost lifetime opportunity. There is no such thing as a ‘catch-up phase’.

Around puberty between eight to ten months of age heifers should reach hip height of 1.2 meters. For joining at thirteen months, they should weigh 360+ kgs and achieve a hip height of 1.30 to 1.35 meters. A target of 85% of heifers pregnant within three cycles requires an average of 1.7 services per conception.

So where do we lose it, especially over summer? As above, inadequate protein certainly is a handicap to growth. For the goal of lifetime production, it is critical that heifers achieve the above growth goals.

Achieving timely pregnancy, especially in seasonal or group calving patterns, is very dependent on vitamin and mineral nutrition. It’s a real gamble relying on forages to supply necessary vitamins and minerals due to both content and bioavailability of both in forages. Supplementation is essential to meet growing heifers’ needs. Where a grain supplement containing a sound vitamin/mineral mix is not feed through the two years from birth to calving, supplementing with a ‘self-feed’ vitamin/mineral mix is essential. Dairytech Nutrition manufactures an all-weather loose lick product for this purpose and has excellent feedback on heifer development and fertility.

Supplementation of Vitamins A, D3 & E , trace minerals of zinc, manganese, cobalt, iodine, and selenium are well documented (NRC 2001) to improve ovarian function and embryo quality. Research shows eight fewer days open and 0.5 fewer services per conception with higher pregnancy rates. Macro elements of magnesium, phosphorous, sulphur, calcium and salt tend to be more involved with growth and skeletal development, but not limited to this. Our ryegrass pastures are very low in calcium especially, a strong argument apart from soil health, to reinstate clovers in our pastures.

Any production animal’s value will rest on a balanced diet. However, it needs to be noted, that, a pregnant animal with an unbalanced or deficient diet will provide the same to the developing foetus. Too often, heifers are left to their own resources on out-blocks or agistment, not just compromising their growth and development, but also, another generation in the unborn calf. Nutrition during pregnancy becomes even more important to meet both heifer and developing calf’s needs for macro and micronutrients.

As a generalisation, pasture is a reasonably well balanced diet for energy, fibre and protein. However, the variations in pasture can be wide as we see in lactating cow diets throughout the year, and even between farms at any given time; no more so than through spring when diets frequently become grass and grain.

Summer pastures generally require supplementation, not just for quality, but more so quantity. Silage certainly can meet this void, but as above, supplementation with self-feed vitamin/mineral loose licks is essential to meet their deficiencies/availabilities in forages. Our heifers, to enjoy longevity as lactating cows, require these nutrients, but so too the developing calf. With sound nutrition, calves are more likely to have healthy birthweights and a strong start to life.

Managing body condition through the heifers first two years has lifelong production and fertility consequences. Adequate energy and protein are essential for a balanced diet. Over conditioned heifers are generally deficient in protein and lack growth of muscle tissue and frame, assuming minerals nutrition is not inadequate. During the months prior to first calving it is essential body condition be well managed. Like dry cows, any over-conditioning or under-conditioning will precipitate energy related disorders of ketosis and displaced abomasum.

Both over-conditioned and under-conditioned heifers will not perform well due to prolonged negative energy balance. Calves from under-conditioned heifers are typically less vigorous.

Well-grown heifers become high performing cows with high dry matter intakes post-calving that persist well into lactation. Fertility and health are serendipitous outcomes of high performance induced in the previous two years of growth and development.

We have the genetics in our herds for far superior performance than Dairy Australia data reveals. Studies at Purina Animal Nutrition Centre (USA) highlighted that high performance can be achieved with longevity and no ‘burnout’. Managing our heifer’s development has significant long-term benefits to the viability of individual farm businesses, but also our industry.

Limestone and Salt

Perhaps the two most abundant compounds on the face of the earth, yet our cows are deficient in both, with significant implications to health, fertility and milk production. Why, perhaps due to their commonness, and we tend to take little notice of things that are very common.

Salt is an essential compound in a cow’s diet for a number of metabolic functions, but also for buffering capacity of saliva in the rumination process. Apart from these important functions, salt will make cows drink water, and there is a direct correlation between water intake and dry matter intake; which naturally drives milk production. Salt should be in the dairy grain mix, but also offered free choice as the cows’ needs can vary daily.

The subject I really want to address is calcium in our cow’s diet. Limestone dressing on pastures is another subject that requires urgent attention. No, or low, calcium in soils will seriously retard plant growth and mineral content of plants. Calcium is the transport system of other minerals in both our soil and our cows’ rumens.

Gary Oetzel, DVM, professor of dairy science at the University of Wisconsin, during a seminar stated: “You ought to respect hypocalcemia, you ought to be afraid of it, and you ought to do everything you can to minimise it”. Hypocalcemia is low blood calcium. Milk Fever in clinical form, but we’ve made massive inroads on milk fever with anionic lead feeds and good transition management reducing incident rates to 2% – 3% of the herd. Despite this, sub-clinical milk fever is reported to run around 60% of all second-plus lactation cows. Heifers are not immune either.

The clinical milk fever cow can be recognised, treated, and back in production relatively easily. The consequences of sub-clinical hypocalcaemia have far more serious effects than we realise, and far more reaching into lactation production, health and fertility. Blood tests are the only real indicator of the degree of hypocalcaemia. Initially, at calving, there are big benefits in oral calcium supplements (drenches or boluses) to help cows cope with “lactational osteoporosis”. This is virtually unavoidable to meet the 300% increase in calcium that fresh cows require. Oetzel estimates sub-clinical hypocalcaemia at four times the cost of clinical milk fever. When research has identified up to 60% of mature cows suffer sub-clinical hypocalcaemia, at four times the cost of clinical milk fever, then this is a very significant cost to farm profit.

Sub-clinical hypocalcaemia is well documented as the prerequisite to a numerous diseases common around calving: obviously clinical milk fever, but add to that, retained membrane, metritis, mastitis, ketosis, and a major industry problem, fertility. Productive life as milking cows can be unnecessarily cut short as a result of sub-optimal calcium nutrition. Our clients that have been proactive in calcium nutrition have seen major decreases in fresh cow mastitis, metritis, and very significant improvements in fertility.

My concern is, in our low calcium ryegrass pastures, this hypocalcemic disorder goes on well past early lactation. A cow producing 30 litres of milk is exporting 36 gm of calcium daily in milk. That’s the calcium content of 100+ gms of limestone. Then there are urinary loses, reabsorption of calcium into bones and metabolic functions requiring calcium. The immune system alone has a high calcium demand.

Dietary calcium deficiencies are common in ryegrass pastures which frequently have little or no clover content these days. Milk protein production is also limited by calcium deficient diets. Ryegrass contains typically around 0.3% calcium. Clover is around 1.4% and Lucerne 1.7%. A recent article in the Australian Dairyfarmer highlighted the need for a return to 30% to 40% clover content in grazing pastures. This article was more about pasture production and soil health and their need for clover, rather than cow nutrition.

Soils have a high need for calcium to function well (transport other nutrients). Obviously, legumes have a high need for soil calcium availability for growth, and their high calcium content. The author of the Dairyfarmer article stated “we’ve lost our way” in pasture production with the neglect of clover. Losing our way is correct. When I started share farming in the 1970’s, applying lime was an annual autumn event. Where I live in SW Victoria we sit on top of a limestone mountain, yet I see very little spreading of lime on pastures. Certainly SW Vic would benefit immensely from gypsum applications. Gypsum will supply sulphur as well as calcium, another element lacking in our soils as a legacy of high analysis fertilisers and urea. Gypsum will restore soil structure allowing for better water and air penetration.

I think the massive uptake of urea use, the demise of super applications, the spraying of broadleaf weeds have all contributed to clover’s departure from our pastures. These are all reversible including broadleaf sprays that are now available and harmless to clover. A return to lime applications must precede sowing of clover. It is not just a soil pH issue, but a locking up of other nutrients that only calcium can undo that needs to happen to ensure good clover establishment and perseverance.

Reestablishment of clover in our pastures will not just increase calcium in the diet of our cows with major benefits to production, health and fertility, but increase pasture harvested per hectare, improve soil nutrient availability to plants, improve soil structure and reduce soil compaction problems prevalent on most dairy farms.

I profess no expertise in agronomy and strongly advise consultation with sound agronomists. Calcium is not a stand-alone cure-all. It is intimately involved with numerous other elements in both soil and animal nutrition. However, calcium is called a macro element, meaning, it is required in large amounts and our capacity to meet this need through grain mixes alone is limited. Increasing calcium in our forages through good pasture clover content will go a long way in improving both pasture and cow health and production. As the Dairyfarmer article said; “we’ve lost our way”. This is not rocket science, but was standard, good-farming practice of 50 years ago.

Leafy summer fodder crops like sorghum have a high need for calcium and respond in yield very significantly when calcium is not a limitation. As one of my clients says; lime is a fertiliser.