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Oliver O'Hara November/December update

Animal Nutrition

Animal Nutrition

  • Results highlight excellent quality silage this year
  • Mineral analysis results – protected Copper is needed
Animal Health

Animal Health

  • Rotavec Corona given to Cows
  • Lice proving difficult to treat

Animal Nutrition

The silage results from FBA yielded positive results in terms of quality silage . Bales made had a  DMD of 76.6% and a CP of 14% . These bales are marked and kept for the priority stock such as weanlings and autumn calving cows. Making top quality silage and feeding it to priority stock while ensure optimum performance while cutting down on the meal bill.

A mineral analysis was also completed of the silage fed to the cows.  The result highlighted normal values for the main macro minerals ie Calcium, Magnesium and Phosphorous. However, there are elevated levels of Molybdenum which could lock up copper in the silage. Therefore , the mineral being fed should contain copper in a protected form to ensure that the available copper is used.

Macro Minerals

Magnesium (Mg):  Magnesium plays a crucial role in mobilising calcium from bones and increasing gut absorption, to reduce milk fever. Low levels of magnesium can also cause slow calving. Magnesium is not stored in the body, so it is very important it be fed right up to calving.

After calving Mg supplementation is required especially on lush spring or autumn grass to prevent grass tetany.  

Phosphorous (P): Makes up approx. 30% of total minerals in the body. A phosphorous deficiency can severly affect reproduction, causing silent heats, irregular oestrus and low conception rates. Low phosphorous is also associated with pica – i.e. eating stones etc.  

Sodium (Na):  Aids in nutrient transfer, waste removal, involved in muscle and heart contraction, rumen and blood pH. Deficiency signs are urine licking, reduced male fertility, lower milk production and depraved eating behaviour.

Calcium (Ca):   Calcium maintains normal muscle function and a deficiency can cause difficult calving’s and retained placenta. Obviously once a cow is lactating the requirement for calcium increases dramatically, it is a deficiency in calcium that cause milk fever.  A cow is unable to physically consume her calcium requirement, she has to mobilise it from her own bones. In order for her to be able to do this post calving, she has to start pre calving. Magnesium aids in this process and this is why minerals high in magnesium are fed pre calving. If calcium is fed pre calving it meets her pre-calving requirement and she won’t have started the process of mobilising calcium from her bones and this will lead to a deficiency after calving, therefore - Do not feed calcium pre calving.

Trace elements

Copper (Cu): Deficiency can lead to small weak calves, scours and decreased milk. In weanlings, it can cause poor growth rates.

Selenium (Se): One of the few elements that can pass through the placenta from the cow to the calf. It is important as a deficiency can cause muscular dystrophy (weakening and wasting of muscle). Some areas are high in Se, so you should test your silage to ensure you do not cause a toxicity. A deficiency can also cause an issue with retained placentas.

Iodine (I): Deficiency can cause small weak calves, dead or hairless calves, or calves that do not want to suck. The animal will have low immunity. It can also lead to poor reproductive performance. It is also not stored in the body and needs to be fed right up to calving.

Cobalt (Co): Involved in the synthesis of B12 by the rumen, deficiencies more often seen in sheep. Can cause a rough coat, poor appetite and anaemia.

Manganese (Mn): A deficiency can affect growth, bone formation and the nervous system leading to poor growth, reproduction and bowing of the joints.

Zinc (Zn): Plays a role in the immune system and repair of damaged tissues. while it is also involved in the synthesis and metabolism of proteins and carbohydrates, teat keratin formation. A deficiency can lead to poor skin, mastitis, slow healing of wounds, bad hoofs and stiff joints. It can also lead to lower conception rates.



Animal Health

The early Spring calvers have been given the Rotavec Corona Vaccine. This vaccine  raises antibodies against rotavirus, coronavirus and E.Cli K99. The calves will gain protection from drinking the fortified colostrum from their mothers.

Lice have been troublesome to treat on the farm and a second dose was required

Lice are divided into two groups:

  1. Biting lice
  2. The long-nosed cattle louse is generally found around the head, neck and dewlap;
  3. The little blue cattle louse tends to cluster on the face, neck, head, under the jaws and may spread to the shoulders, back and tail when infestation is heavy;
  4. The short-nosed cattle louse is commonly found on the skin of the poll, at the base of the horns and ears and around the eyes and nostrils and the tail switch.

Biting lice have robust round heads and feed on skin and hair debris, bacteria and hair. There is generally one species of biting lice found in cattle – Bovicola bovis (also called Damalinia bovis). It is usually found on the head, neck, shoulders, back and rump of cattle.

In extreme infestations, the lice may spread down the sides and even cover the reset of the body. This louse causes extreme itching by cattle and self-trauma may cause wounds which in turn may lead to secondary bacterial infections. 

Suckling lice

Sucking lice have piercing mouthparts and feed on the blood and fluid of cattle. There are generally three species of sucking lice found on cattle:


  • A range of synthetic pyrethroids in spot-on or pour-on formulations are available (deltamethrin, cypermethrin).These will treat biting lice and sucking lice.
  • Injectable macrocyclic lactones (ML’s) are also available (ivermectin, eprinomectin, moxidectin, doramectin). Injectable treatments generally treat sucking lice, but will also aid in the control of biting lice. Pour on MLs will treat both sucking and biting lice.
  • Always read the label to ensure that you are treating the correct parasite, applying the product correctly, know the retreatment time, calibrate the applicator and the withdrawal period.
  • Many of the different products treat other external and internal parasites as well. When introducing new animals to the herd they should be treated and quarantined.