There’s been much discussion on the topic of the optimal age at first calving (AFC) however numerous studies have shown that targeting an age of 24 months at first calving can be optimal for lifetime performance. Animals calving for the first time between 23 and 25 months have shown improved fertility, increased milk production and better longevity compared to older animals at calving. Also the non-productive portion of the animal’s life is reduced and the animal can enter the herd and start its payback sooner.
Despite the documented benefits according to recent data from NMR the average AFC in the UK is currently 28.7 months with less than 10% of herds achieving an AFC under 25 months which leaves us some way behind the 25-month average in US herds.
Achieving successful and consistent calvings at 24 months is dependent on many factors and will require an effective heifer rearing management plan to achieve bodyweight targets at the point of breeding.
In practice for a Holstein heifer this equates to maintaining an average growth rate of 750g/ day. While optimising genetics, employing good feeding practices and supplying the correct nutrition are hugely important in achieving the required growth, focus should also be put upon ensuring that the animals are not compromised by disease.
In recent studies nearly 50% of calves in UK dairies have been affected by scours in the pre-weaning period. Several pathogens such as Coccidia, Cryptosporidia, E.Coli, and Salmonella can cause calf diarrhoea which can have a huge impact on the animals growth.
Similarly almost 50% of UK calves have suffered from respiratory disease in the same period. Various studies have shown that cases of these diseases have delayed the AFC by three months and doubled the likelihood of animals not completing the first lactation.
Respiratory diseases such as pneumonia are caused by bacteria and viruses. However there are predisposing factors that are of great significance. Dampness, drafts, chilling and toxic gases such ammonia can make the animals more susceptible to disease outbreaks.
When ammonia builds up to levels where the smell is noticeable then the animal’s lung defences are damaged. The immune system is also compromised and the pathogens that are present in the housing can lead to animals contracting diseases. The challenge from patho - gens in the housing can be reduced by using a dry bedding hygiene product such as Stalosan F which kills many harmful bacteria such as Coccidia, Cryptosporidia, E.Coli and Salmonella. In addition, Stalosan F also binds ammonia in the environment preventing levels building up and affecting the calf’s immunity.
Calf scour can be caused by various patho - gens at different ages, however more recently diarrhoea caused by parasites is an increasing problem (see figure).
Coccidiosis and Cryptosporidiosis are parasitic diseases resulting in infectious enteritis caused by parasites living in the intestinal cells and outbreaks of these diseases are pre-disposed by poor hygiene. Parasites destroy the intestinal cells, resulting in a lower surface area in the intestine for absorption of nutrients and therefore animals will have a lower weight gain and feed efficiency.
The best cure for these diseases is prevention and as they occur at different ages then it’s im portant to protect animals from the beginning of their lives. VitCox is a new feed supplement that provides control of parasites. It is based on plant extracts that reduce the parasitic load by preventing the development of parasites.
VitCox can be administered from the start by feeding in the milk to provide a preventative effect during the per-weaning period. VitCox is a natural solution that does not require prescription and can reduce the requirement of pre scription medicines. It has no retention time and can be used in organic farming. Trials in young ruminants showed increased daily gain by 13% and lower oocyst levels in the manure when supplementing with VitCox.
The product has been used in Denmark and in the UK for a short period with excellent feedback. Leif Sørig from Denmark comments:
“We’ve used VitCox for four months now, and we have noticed a distinct decrease in cases of diarrhoea. Previously we used prescription drugs which have now have been replaced."
“We have not experienced the side effects of the prescription drugs and looking back the calves are performing much better now than before. The good thing about VitCox is the fact that it is a natural product with no negative taste impact on milk, like other products may have. It is easy and harmless to handle and it is possible to save money because of the reduced veterinary costs."
|Impact of a deficit of trace minerals|
|Manganese||Weak/irregular/silent heats. Increased abortions. Reduced conception rates, birth weights and weak calves.||Low level in grain and clover. An increasing pH in the soil reduces the level of Manganese.|
|Zinc||Reduced appetite. Reduced conception rate and immune response. Weak hoof horn.||An increasing pH in the soil reduces the level of Zinc.|
|Copper||Rough/discoloured hair coat. Unthriftiness. Reduced growth rate. Diarrhoea.||Copper in dried forage is more available than in fresh grass. Young grass passes rapidly through intestine reducing absorption.|
|Cobalt||Deficiency of vitamin B12. Reduced feed intakes. Loss of condition, weakness, rough hair coat.||Deficiency often occurs in light, unfertilised soils. An increasing pH in the soil reduces the level of Cobalt.|
|Iodine||Reproductive failures including weak or stillborn calves, delayed oestrus and abortions. Reduced appetite.||Rapeseed, clover and soyabean affect the uptake of Iodine. Potassium and Selenium can also affect uptake of Iodine.|
|Selenium||Degradation of muscles. Poor immune function. Retained placenta/abortions. Weak or stillborn calves. Pneumonia with newborn calves.||Many areas of the UK are low in selenium especially areas with poorly aerated acid soils. Interacts closely with vitamin E in muscle and immune function.|
Twice daily Leif measures out the dosage of VitCox, so that the calf receives 2 x 2.5 ml daily for one week. Then the dosage is gradually reduced over the next three days. When the calf is 14 to 18 days old, it is moved into a community pen and is given five ml of VitCox daily for five days. “In doing so the cases of di - arrhoea are kept down at a minimum compared to earlier when we found that problems started to develop again after transfer”.
Grazing heifers should have access to minerals in order to ensure satisfactory growth through - out the summer. Apart from needing fodder rich in energy and protein, they also need a balanced supply of minerals and vitamins to provide good body growth, a strong immune system and optimum fertility. During sum - mer grazing macro-minerals are essential for a healthy gr owth of the skeleton and body of the heifers as calcium, phosphorus, magnesium and sulphur all have a positive influence on development of the bone structure. Phosphorus is also required in energy conversion and in combination with magnesium it is also important for the nervous system. In other words, many functions in the body rely on a sufficient intake of macro-minerals.
An adequate supply of trace minerals is critical too. The table shows the impact of a deficit of important trace minerals.
Selenium in particular, plays an important role in the body as it protects cell membranes from injury and degradation. A lack of selenium leads to a suppressed immune system. Taking into account the insufficient level of selenium in grass, the allocation of mineral supplements that provide adequate levels of selenium are imperative.
Free access to minerals that cover the heifer’s requirement for macro and trace minerals ensures the animal receives the nutrients that are essential for the its health, growth and reproductive performance. VM Heifer is a free access mineral that’s been specially designed to meet the animal’s requirements of the important minerals and uses raw materials that create a dust free, granular mineral that is highly palatable. Heifers are lured to eat the minerals which are enhanced by a natural flavouring agent. During the summer a daily allowance of 70-80 grams fully covers the need of heifers on pasture.
The simplest and most cost effective way of supplying free access minerals is by means of MicroFeeders.
These are mineral feeders designed as self-raising containers, which protect the minerals from being spilt and with a covered top to prevent deterioration from rain, manure and urine. They are made of solid plastic and are maintenance-free. Each MicroFeeder holds approx. 15 to 20kg of minerals and can supply around 40 to 50 animals.
Vitfoss MicroFeeders, along with our specially designed free access mineral supplements, pr ovide an easy and efficient way to meet the mineral requirements of heifers during summer grazing.
Vitfoss will be exhibiting at the Livestock Event or for more information visit www.vitfoss.com