February 2021 Monthly Management

Milk Fever – What To Look Out For; Spring Grassland Management; Grass & Grazing

22 February 2021

Milk Fever – What To Look Out For

Clinical milk fever is a significant issue on farms this year. As well as the clinical condition, subclinical milk fever can be a gateway for many other diseases such as retained cleanings, poor immunity, slow calving’s, still births, poor feed intakes, stomach issues and ketosis. These metabolic disorders have a significant economic cost.

Milk Fever Rt. Placenta Ketosis LDA
Disorder % 4 1.5 0.5 2
Culls% 5 6 5 8
Delayed Conception,Days 13 15 10 12
Discarded Milk-kgs 0 150 0
Lost Milk-kgs 130 250 230 575
C. Guard,Cornell-1998

Average Cost - € €312 €392 €320 €515

No. Of Cows - 16,141

% Metabolic Disorders 3.8 4.7 1 1
Av.No.Of Cows /Herd - 106 4 5 1 1
€ per Herd €1,248 €1,960 €320 €515
Total Cost - € €4,043.00

Milk fever is a multifactorial disease but the main risk factors on farm are high potassium silage, old cows, fat cows and environment (facilities, feed space, cubicles, etc). Where you have a problem on you farm you will need to look at the variables that impact on the risk and severity of the problem.

Potassium – high levels are influenced slurry, fertiliser application and timing in silage crops. Herds with annual problems will need to look at reducing potassium levels in silage. High potassium effects the cow’s ability to mobilise calcium at calving and can also affect magnesium absorption.

Magnesium is an important mineral in the calcium metabolism processes. It is difficult to maintain long-term storage of this mineral so daily supplementation in needed (minimum 30 grams/day) and in cases where potash is an issue, magnesium levels need to be increased further. Feeding a good quality pre-calver with added magnesium is a good practice before calving.

Breed – Jersey cross cows are more susceptible to the condition than Friesian type cows – they have a lower ability to mobilise calcium from their bodies compared to other breeds. Very high yielding Holstein Friesian type cows are also very susceptible to milk fever due to the surge in demand of calcium for milk production.

A useful means of identifying any potential mineral imbalances is by carrying out mineral analysis of silage – contact Drinagh Advisors to arrange a test if required. If antagonistic minerals are prevalent in the mineral report, then the addition of dry cow salts (anions) can help to counter any issues on farms where problems are common.


Cow Condition – the condition of cows, particularly older cows need to be managed so they are not over-fat at calving. Cows over four lactations need to be monitored closely.

For high-risk cows, some additional preventative measures can help. The use of oral calcium in drench or bolus form has been shown to reduce the risk and severity of symptoms.

Getting the cow to eat and drink immediately after calving is important in terms of reducing the risk of the disease. Cows normally drink 20 litres of warm water immediately after calving if offered from a bucket – this will encourage feed intakes and following up with a few kg of dairy nuts will give her a good start. Fresh forage should always be available in the calving pen – ensuring the cow eats a good quantity of fresh forage as soon as possible after calving will also be a help.

As milk fever is a metabolic disease directly related with feeding management, adopting an appropriate feeding strategy during the pregnancy period and immediately after calving can prevent the occurrence of milk fever. All predisposing factors need to be considered to help herd owners avoid both clinical and subclinical milk fever successfully.

Spring Grassland Management

The most efficient way to allocate grass in the spring is by using a spring rotation planner. The spring rotation planner (SRP) allocates an appropriate proportion of the farm each day, from February 1st to early April. The SRP will vary from farm to farm, depending on when turnout can occur (weather, calving pattern, soil type, etc...)

Week-end date % of farm grazed at week-end
1st February Start grazing
1st March 30% grazed
17th March 60% grazed
7th April Start 2nd rotation

For the plan to be successful, the following is required:

  • Stick to the planned area per day - Skipping ahead of the area planned will result in a short first rotation. The knock-on effect of this will be poorer utilization and less grass available at the start of the second rotation.
  • On/Off grazing in wet weather - On/off grazing with 2-3 hours of grass access after each milking followed by rehousing is an excellent way to allocate grass and protect swards during difficult weather conditions. In this instance when dry matter intakes are compromised, appropriate concentrate supplementation is required.
  • Use a strip wire – Split paddocks into 12-hour blocks plus the area already grazed should be back fenced to avoid any unnecessary pasture damage. The use of spur roadways is a useful form of temporary access to paddocks, minimising ground damage in the process.

split paddocks

Grass & Grazing

This months feature farm is Donie O’Donovan, Cullinagh, Skibbereen

Grazing conditions have been tough so far this Spring.
Cows went out on February 7th and were out most days since with the back fence up behind them.


Cows will be out full time or on an on/off basis and once conditions allow.

The target will be to start the second rotation around April 5th. To achieve this, areas with lower covers will be grazed first until numbers calved and feed intakes increase. The opening average farm cover was 1,076kgDM/ha. Growth has been low due to cold temperature in February. To date, 50% of the herd has calved since 26th January. They are on 4kg of Drinagh High Maize 19% in the parlour. There has been a few cases of milk fever and the plan is to bolus at risk cows for the rest of the calving period. 20% of the milking platform has got slurry but conditions were unsuitable, so no Nitrogen has been spread to date this year. As soon as conditions allow 30 units of urea will go out.

Avg. Farm Cover 1076kg DM/ha
Avg. Farm Cover 1st Dec 2020 800kg DM/ha
Over winter Growth 4.6kg DM/ha
Current Growth 4kg DM/ha
Pre-Grazing Yield 1,200kg DM/ha
Cows calved at 26th Jan-16th Feb 50% calved
Diet 4kg 19% Hi-Maize, 5kg DM Grass, 5kg DM silage