Herd Lameness

In New Zealand many dairy farmers still a high percentage of lameness in their herds, as many of you will know I have for many years claimed that 90% of lameness is a nutritional factor, a result of diet. Yes a percentage can be blamed on bad race ways, stones etc, but the majority is nutritional. The percentage of lameness and empty cows in many of our herds is still unacceptable, especially when information is available to significantly reduce or eliminate these issues. Good races are only part of the lameness cure, nutrition holds the key. The issues that are adversely affecting hoof health are also linked to lower conception and general health. Excess protein (nitrogen) holds the key.  yes some N applied to the soil is great but too much nitrogen in the pasture. Remember protein is nitrogen x 6.25. So a good fresh pasture containing 5% N will contain 32.5% protein when the cow only requires approx 16% when milking and 10 to 12% when dry. Dealing with this surplus N = high blood N (BUN) = urea production in the liver = weight loss = high milk urea (MUN) = lower quality milk = urea discharge through the kidneys = pasture urea burns. Lameness occurs as high blood nitrogen = increased histamine production = dilation of the arteries around the heart = blood pooling in the feet = inflammation = foot scald = lameness.


Fertilisers must not only be applied to promote production but also to provide essential elements to optimise animal health, eg. Trace elements, calcium, magnesium, and the right form of N and sulphur.  Also fertilisers that will influence the way pasture plants handle the various forms of N.  Having the desired level of N, 4.5-5.5%, in pastures is one thing, having the right forms of N is another.  Remember crude protein is N multiplied by 6.25.  N in pasture can be in the form of nitrates, nitrites or as amino acids.  Some forms of N are toxic, others desirable.  As the weather changes so does the form of N in the pasture and so also changes the extent of lameness, animal health and fertility.  Frosted pasture, higher hours of sunlight and slower growing conditions see higher percentages of desirable forms of N.  Toxic forms of N are high during periods of flush growth, growth during periods of overcast weather, growth following dry spells and high levels of growth following some N applications, so it is critical that you understand both animal and pasture requirements when planning your fertiliser programme. As we know pasture and animal requirements are very different.


Timing of application is also important for stock health.  Applications of NPK just prior to, or in the few weeks following calving can have detrimental effects on cow health with many deaths occurring.  With calving and during early lactation the cow is put under a period of tremendous stress.  Increasing this stress with bad timing of a fertiliser application is less than cost effective.  A good example is the grazing of areas just prior to or in the few weeks following calving, that have been recently treated with potash or urea or some phosphates.  Do not apply these products during this period, and if you need to apply N use SOA, save the urea and potash until after the soil temperature increases, eg. Late September/early October.  I see or hear of too many herds loaded with metabolic problems as a result of poor fertiliser timing.’

Understand what your cow is going through?  Understand her requirements?

Understand how to predict problems that she is likely to face before a problem arises.  We all like to see our bank balance grow, looking after each individual cow, providing her needs from one season to the next is the greatest way to achieve this goal.

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