Every mother should be given care so that the baby is born healthy, there are treatments and supplements that are recommended to have a healthy baby and mother. This also applies to the pregnant cow to make sure that the cow will give birth to a healthy calf which will be able to adapt to the environment. This article will cover the nutrient supplements that are to be given to the pregnant cow during its gestation period.
There are some issues which the cow may go through during calving, some of these issues include retained fetal membranes (RFM), lazy calving, calving difficulty (dystocia), milk fever, calf death and poor calf health. For example maternal deficiency of trace minerals and Vitamin E in late pregnancy can compromise the immune system of the calf. This may increase susceptibility to scour, pneumonia, navel-ill, joint-ill, etc. It is generally advised to feed dry cow mineral and vitamins for approximately six weeks pre-calving. This is in order to combat deficiencies in the total dietary intake. For example grass silage can be deficient in major minerals such as phosphorus (P) and magnesium (Mg) and trace minerals such as iodine (I), copper (Cu), selenium (Se) and cobalt (Co). The precise amount and proportion of supplementary minerals and vitamins depends on the nature and extent of any shortfall, potential dietary interactions and on the intensity of production. Thus, an analysis of your feed can identify your specific problems more accurately and may indicate a deficiency, or indeed a sufficiency, of the minerals and vitamins which you test for. The following will focus on calf-related issues.
Energy and protein nutrition
The developing foetal calf is afforded a high priority for maternal nutrients. Foetal requirements for energy and protein are significant at the latter stages of gestation, for example in late pregnancy energy requirements increase to 1.3-1.5 times maintenance. Therefore rations for dry cows must contain sufficient energy to support maintenance and foetal growth. Providing excess nutrients, particularly energy to put condition on thin cows towards the end of the dry period might negatively affect survival by increasing the incidence of over conditioning and per parturient disorders. Dystocia (calving difficulty) is often associated with over-conditioned (fat) cows. Dystocia profoundly affects calf health and survival, as well as cow lactation and reproductive performance. Calves born from cows with dystocia also had poorer rates of bodyweight gain. Thus any factors which are associated with dystocia are in fact associated with reduced calf survival and health and as a result management to avoid dystocia is critical to calf performance.
Low dietary iodine (I) intake during pregnancy has been associated on the cow side with an increased incidence of stillbirths and calving problems such as retained fetal membranes (RFM) and lazy calving and on the calf side with an increased incidence of small and weak calves, increased incidence of goitre, decreased resistance to hypothermia (losing more body heat than heat produced), decreased survival and low immunity. Cows recycle Iodine poorly, which means that Iodine is not stored in the body and so it must be supplied in the diet. For example, grass silage the principle forage offered to dry cows is generally low in minerals such as selenium, iodine, copper and cobalt. This resulted in Iodine being routinely supplemented. However it is important to remember that toxicity can be as dangerous as deficiency! A blood test for plasma inorganic Iodine (PII) is the most reliable way to confirm low I status.
Selenium (Se) is another trace mineral which is often implicated in cases of lazy calving and RFM. Supplementary Selenium given to animals reared in areas with adequate Selenium proved ineffective. Indeed high Selenium areas do exist, and in this case it is dangerous to feed supplementary Se due to the potential for Se toxicity. Selenium is one of the minerals which crosses the placenta from the cow to the calf and so Selenium supplementation of pregnant cows has been shown to increase the Selenium reserves in newborn calves. Selenium and vitamin E are often considered together as they have a similar function in the animal as antioxidants, guarding cells against the potentially destructive free radical compounds formed during cellular metabolism.
Vitamin E is a generic name for a series of lipid-soluble compounds called tocopherols and tocotrienols. In contrast to Se, the transfer of vitamin E across the placenta from the cow to the calf is low. As a result the calf is born with low vitamin E status and is highly dependent on an adequate intake of colostrum, and then milk or milk replacer, to obtain vitamin E during early postnatal life. The vitamin E content of colostrum is usually low if dry cows do not consume sufficient vitamin E. Maize silage, beet and high moisture grain can often be particularly low in vitamin E. Ensiled forages can also have vitamin E concentrations that fall to quite low levels after a period of months.
Dry cows who consume an increased intake of vitamin E during the dry period have colostrum with a significantly elevated vitamin E content. Ensuring that the calf receives an adequate supply of vitamin E is important as vitamin E is required for good health and immune function. Vitamin E is also beneficial for the cow herself, as like Se, it helps prevent retained fetal membranes (RFM).
Vitamins A and D
Like vitamin E, vitamins A (sometimes referred to as beta carotene) and D do not cross the placenta in significant amounts and so the calf relies upon ingestion of colostrum for these vitamins. As a result it is extremely important that the colostrum contains adequate amounts of these vitamins. Vitamin A plays an important role in combating infection and it increases disease resistance and stimulates the immune system. If calves remain deficient in these vitamins, by consuming inadequate quantities in the colostrum, they are susceptible to infection, which could lead to scours and pneumonia.
Cows grazing outdoors generally have high levels of vitamin D due to being outdoors and obtain high levels of vitamin A from the pasture. However indoors on winter diets concentrations of these vitamins can be variable and in the absence of accurate information on dietary and animal vitamins status, supplementation is often practiced. In addition to the problems faced by the calves illustrated above, cows that have a deficiency in vitamin A can have increased prevalence of retained fetal membranes (RFM). They can also produce dead, weak or blind calves because vitamin A is needed for normal growth and development including growth of the foetus.