Ensuring that a new born calf gets the correct amount of good quality colostrum as soon as possible after birth is paramount to produce a healthy calf.
Measuring colostrum quality
The use of a colostrometer or refractometer to measure the amount of immunoglobulins within the colostrum is essential to make sure that the calf receives enough passive immunity from its mother. But…is there anything we can do to ensure that the cow has the best chance of producing good quality colostrum?
Many of the modern dairy cows produce so much milk soon after calving that it has a dilution effect on the quality of the colostrum. So, ensuring that the content of the colostrum is of top quality is paramount in giving the calf the best chance in life.
‘High Quality Colostrum’ can be defined as having at least 50 g/L IgG. This should ideally be farm specific in regard to the diseases that calves are likely to be exposed to.
It should also be clean with a low bacterial count and free from any pathogens that can be transferred within it. Finally it should be nutritious containing correct constituents to support a healthy calf.
The process of colostrum production begins several weeks before calving and stops abruptly when the calf is born. During this time, large amounts of IgG and other immune factors are selectively transferred from the bloodstream of the cow into colostrum. This starts approximately 5 weeks prior to calving and is maximal in the last 2 weeks before calving. (Maunsell, 2014).
So with colostrum production taking place for this amount of time, the way that the dry cow is managed can greatly impact the quality of colostrum produced.
Breed can also affect colostrum quality. Traditionally, Holsteins have been thought to have lower colostral IgG concentrations than other dairy breeds. However, a recent national survey of colostrum quality in the US did not find any significant difference in IgG concentration of colostrum of Holstein (74 g/L) and Jersey (66 g/L) cows (Morrill et al., 2012).
On average, Heifers entering into their first lactation produce less colostrum, with less immunoglobulins. Colostral quality continues to increase with parity after the second calving, and older cows generally have the best quality colostrum (Morrill et al., 2012). However, this said heifers that have been managed well can produce very high quality colostrum therefore should not be discarded before it has been tested.
Nardone et al. (1997) found that heifers subjected to heat stress for the last 3 weeks prior to calving produced colostrum with a much lower IgG concentration than non-heat-stressed controls. So it is important to make sure that dry cows and heifers are kept in a good environment with adequate water supply and good ventilation, especially within the summer months.
Cows seem to need at least a 3-4 week dry period to produce good quality colostrum, and when the dry period is very short or there is no dry period, colostrum is often poor quality (Rastani et al., 2005). It is not advised to feed colostrum from cows that have less than a 3 week dry period. Even if 50 g/L IgG are present, there has not been enough time for all anti bodies and any vaccines used within the dry period to be transferred into the colostrum.
There are many different opinions and strategies to produce higher quality colostrum, but there is very little research behind them.
Older studies in beef cattle showed that pre-partum nutrition did not affect colostrum IgG content, even when protein and energy were severely restricted. However, when diets very low in protein were fed, the ability of the calf to absorb IgG was compromised (Maunsell, 2014).
Selenium and possibly other trace minerals and vitamins involved in immune function may influence colostrum quality when they are deficient. Cows fed a pre-partum diet deficient in selenium and vitamin E produce less colostrum and lower total mass of colostral IgG than cows fed the same diet but supplemented with injections of vitamin E and selenium. There was no effect on IgG concentration (Lacetera et al., 1996).
Currently there is very little literature to support many of the nutritional plans used in dry cows to improve colostrum quality. Although, it is very important to stress that diets should be tailored to specifically maximise the health of the dry cow within the pre partum period.
In conclusion, a few key points that should be taken into consideration:
- Transfer of antibodies (especially IgG) from the blood of the cow into colostrum starts about 5 weeks prior to calving, and is maximal in the last 2 weeks before calving.
- The older the cow, the better the colostrum – but there’s lots of individual variation! On average, first-calf heifer colostrum is lower in volume and IgG concentration than that from older cows. However, many heifers produce very good quality colostrum. Don’t automatically discard heifer colostrum!
- Don’t automatically discard high volume first-milking colostrum if it was collected within a few hours of calving; colostrum should be tested and only discarded if low quality.
- Discard bloody colostrum, colostrum from sick cows, from cows with clinical mastitis, from cows that are known to be infected with chronic diseases such as Johne’s disease or Mycoplasma, and from cows that leak colostrum extensively prior to calving.
- Heat stress may reduce the quality of colostrum, especially in heifers.
- Dry period length should be at least 3-4 weeks to maximize colostrum quality.
If you would like more information on this please contact your Wynnstay Dairy Specialist.
Lacetera, N, U. Bernabucci, B. Ronchi et al. 1996. Effects of selenium and vitamin E administration during a late stage of pregnancy on colostrum and milk production in dairy cows, and on passive immunity and growth of their offspring. Am. J. Vet. Res. 57:1776-80.
Maunsell, F, 2014. Cow Factors That Influence Colostrum Quality. University of Florida, College of Veterinary Medicine
Morrill, K.M., E. Conrad, A. Lago et al. 2012. Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States. J. Dairy Sci. 95:3997-4005.
Nardone, A., N. Lacetera, U. Bernabucci et al. 1997. Composition of colostrum from dairy heifers exposed to high air temperatures during late pregnancy and the early postpartum period. J. Dairy Sci. 80:838-844.
Rastani, R.R., R.R. Brummer, S.J. Bertics et al. 2005. Reducing dry period length to simplify feeding transition cows: milk production, energy balance and metabolic profiles. J. Dairy Sci. 88:1004-1014.