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

John Lyne

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