The First Month of Lactation - Minimising Ketosis

A good start to a cow’s season requires careful management through the springer and colostrum period to ensure that she maintains a high dry matter intake. Initial focus should be placed on prevention of metabolic disease, optimising immune function, adequate feed allocation and manipulating cow behaviour.
However, the first month of lactation beyond the colostrum mob is still very critical. Most cows will spend this period in negative energy balance – i.e. more energy is leaving their system than coming in and therefore they will lose body condition. This is why providing consistently high feed quality is imperative. We are already seeing many farms that are struggling to manage very high pre-graze covers due to good growth rates through the winter. These are impacting voluntary intakes and may have lower ME. Cows in significant negative energy balance may develop clinical or sub-clinical ketosis. Ketones are a by-product of inefficient fat break down and have a side effect of further appetite suppression.
Cows which are well fed/have a good appetite in the first month of lactation will lose less weight and have better mating performance. Try some of the following:

• Optimal pre-graze covers of 3,000 to 3,400 kgDM/ha in the first round will ensure good quality and easy harvest for the cow. You still need to maintain a residual at 1,550-1,600kgDM/ha to ensure quality in subsequent rounds.

• Aim to get your milking cows eating 4% of body weight in dry matter ASAP.

• Know what your daily cow requirement is and calculate your allocation every day - where feed deficits exist on any given day fill it with appropriate supplement.

• Use monensin (Rumenox/Rumensin TT), to increase feed conversion efficiency, by driving Proprionate production. Clinical trials show boost in milk protein production and far less BCS loss. Use strategically from calving up until end of
  mating.

• Internal parasites – the biggest impact these have is on appetite suppression. Almost all farms will have high levels of over wintered larvae this year. Aim to drench your herd by early/mid September.

• Vitamin B12 – is a requirement for energy extraction. Deficient cows will lose appetite. We see B12 levels drop at the same time as spring grass goes lush. This is partly due to rapid transit times through the gut impeding B12 absorption. A good rule of thumb is when faeces starts
  becoming loose look to give Vit B12.

Sedation and Metacam for Calves at Debudding

A large NZ trial published last year looked at the benefit of sedation and Metacam (pain relief) on calves at debudding. The results showed:

• Calves that were give Metacam and sedated along with local anaesthetic grew significantly more in the 7 days after debudding by 144grams/day compared to calves that were only given local anaesthetic.

• Sedation improved all the behavioural signs and the pain sensitivity measured in the 22 hours after debudding.

• Metacam improved some of the behavioural signs in calves that were only given local anaesthetic.

The effect of Metacam agrees with a large international study summarising 17 trials which showed NSAIDS (i.e. Metacam) reduces the signs of pain for 6 hours after debudding when used in calves that were given local anaesthetic.

• It is worth considering the use of our Vet Centre debudding teams that use sedation and/or Metacam to improve the outcomes of calves at debudding time.

Finally just a reminder that the Animal Welfare laws have changed and all calves must be given an effective local anaesthetic block prior to debudded. To be able to use local anaesthetic you have to go through an accreditation/reaccreditation process with one of our vets. Alternatively you can use our debudding service or a debudder that has a VOI to use local.

Calf Milk Replacers - Milk based vs Whey based Products

There are two main types of calf milk replacer (CMR) available on the market - milk based CMR and whey based CMR. What is the difference?

They differ on the component of the milk fraction on which they are based - i.e. casein vs whey based.

Casein Based CMR

• Are digested like whole milk, forming a 'casein curd’ in the abomasum. Failure of a curd to form can lead to nutritional scours. Good curd formation = good quality CMR. Poor curd formation = poor quality CMR.

Whey Based CMR

• Whey proteins are digested in the small intestine and do not form a curd in the abomasum. This aids in quicker digestion = more room for meal = GOOD!!! (quicker digestion encourages earlier
  dry matter intake). It also lessens the chances of nutritional scours and abomasal bloat due to the lack of a curd formation.

• A whey based product will move through a calf in only 2-3 hours, compared to 5-8 hours for traditional curding (casein) products. Globally whey based milk replacers are commonly used and lead the market in the US and Europe.

Before deciding to use a milk replacer you should weigh up the advantages and disadvantages for your calf rearing system. Ease of handling with automated calf feeding systems, high milk prices, minimal waste milk and disease control are reasons why they may be favoured on some farms. Only high quality reputable products should be used otherwise health problems and poor growth rates may result. And remember consistency is key - always mix according to the manufacturer's directions!!!

Phosphate Supplements for Fodder Beet

It is a well-established fact that Fodderbeet contains low levels of phosphate, although there is variation between crops depending on existing soil Olsen P levels.

Sustained periods of high FB intakes will lead to Phosphate deficiency and bone depletion. This will exhibit in low DM intakes, metabolic disease around calving, poor early season productions and increase in bone deformities or breaks in younger stock.

We recommend that all cows, heifers and calves that are receiving more than 60% of diet in FB over the winter receive a phosphate supplement.

Fodder Beet Loose Lick Blend

• Supplies essential phosphorus requirements plus a balanced Trace Mineral Blend is a highly palatable formulation.

• Is a free choice lick

• At a 70g daily cow dose the cost is ~11c/cow/day

One bin per 50 cows is spread-out in paddock and topped up every 1-2 days.

Bovine Adenovirus in R1 Dairy Calves

What is Bovine Adenovirus?

• Bovine Adenovirus (BAdV) is a viral disease that is mainly seen in 6-12 month old calves.

• Outbreaks are typically seen during autumn, winter and spring months.

• It is primarily an acute gastro-intestinal disease, but calves may also have respiratory signs.

BAdV was noted as a disease of increasing occurrence in R1’s during 2014/15. The practice sees 3-4 cases/year.

How do we know?

• Outbreaks tend to be short in duration and although a large number of calves within a mob can be affected mortality rates tend to be low (ie. maybe 1-2 deaths in a group of 160).

• A presumptive diagnosis can often be made based on the history.

• A post mortem is important to confirm specific gastro-intestinal changes from samples sent to the lab.

Case Study - March 2020

• Grazier found two calves from a mob of 160, acutely dead within a day of each other.

• Noted the day before that a couple appeared to be a little bit dull/depressed.

Differential Diagnoses for Enteric Disease & Sudden Death in Calves

Yersinia, Salmonella, mucosal disease, GI parasites, toxicity, clostridial deaths, nitrate poisoning.

History

• Calves had received two doses of a 10-in-1 vaccine.

• Drenching was up to date. No known access to any toxicities.

• PM performed on one of the calves. Very fluidlike intestinal contents.

• Samples sent to the lab - a diagnosis of BAdV was confirmed based on histopathology of the intestine. Viral inclusion bodies seen in the GI tract confirms the diagnosis.

No more deaths were seen in this mob, however about half of the remaining calves appeared a
little bit ‘dull’, ears flat, and slightly snotty nose/slightly gunky eyes. Calves were on liveweight
target however weight gains had fallen in affected calves to 200-300 grams/day. A week or so later
they were looking a lot better and had picked up again. Often the remainder of the mob appear to
remain relatively unscathed and in general good health.

One calf from this mob had been diagnosed with Yersinia infection 3 weeks prior to this outbreak
(lab confirmed diagnosis) and although it had been separated, it was possible that in this case
Yersinia infection may have played a role in disease development. Bovine Adenoviruses are
widespread in the environment and given the relatively low prevalence of disease it is likely
that host and environmental factors play a role in disease development. Cold weather conditions, feed shortages, recent transport, ill thrift, and concurrent parasitism all have the potential to cause stress and predispose to opportunistic infections.

An interesting disease that we have seen more of in the last few years, and certainly on the
differential list when you see ‘sudden death’ in calves.