Hugh Chester-Jones, Animal Scientist, Southern Research and Outreach Center

November 26, 2005

At the recent Holstein-Beef conference held in Rochester on November 2-3, a number of presenters from around the country addressed their perspectives on calf nutrition and health. Some key points are provided below.

Role of immunoglobulin and sources – Dairy calves can effectively absorb large Ig molecules up to, but not beyond, 20-24 hours after birth, depending on the type. Attaining consistent optimal Passive Immunity Transfer (PIT) is still a challenge on many dairy operations. Evidence indicates that either calves are not fed sufficient colostrum Ig or are unable to absorb IgG efficiently. By 12 hours after birth, increasing levels of enzyme secretions in the small intestine enhance the degradation and reduce the effectiveness of IgG. The acceptable limits of PIT are at, or above, 10 g/L of IgG in serum or total serum proteins of ≥ 5.5 g/100ml. Calves have an incremental greater risk to disease as initial Ig concentrations decline below these lower limits. There is evidence that IgG initially absorbed from colostrum is re-secreted into the intestine by crypt cells. These IgG help to reduce the incidence and severity of many infections such as E. coli, rotavirus and cryptosporidium.

To aid in providing adequate colostrum, alternatives are available, such as colostrum supplements or colostrum replacers. Colostrum supplements (CS) usually provide <100 g of IgG/dose formulated to compliment maternal colostrum and are described as providing specific or non-specific IgG. Source of IgG in CS are colostrum, milk, blood and eggs (processing of egg IgY and antibody production). Absorption of IgG in CS has been inconsistent. Colostrum replacers (CR) usually provide >100 g of IgG/dose but also contain a complete nutrient profile required by the calf (energy, fat, proteins, vitamins and minerals). Colostrum and plasma are sources of IgG used for development of CR which have provided successful PIT.

There are limitations of CS and CR use. They relate to differences in antibody specificity to environmental antigens on the farm. So absorption level is irrelevant if protection is not forthcoming. The other essential components of maternal colostrum have yet to be effectively duplicated in CS or CR. The use of highly concentrated IgG sources for calves after 24 hours of age appear to also help intestinal immunity and health.

The volume of first colostrum feeding is important. To support the premise, a recent University of Arizona study, Faber and others (2005), fed Brown Swiss heifer calves 2 L or 4 L of high quality colostrum within 1 hour after birth but fed similar 2nd and subsequent feeding levels. Feeding 4 L vs 2 L of colostrum translated into lower calf health costs ($15/calf) due to less calves requiring repeated treatments. Calves fed 4 L colostrum had faster growth rates (0.5 lbs/day) up to 500 days of age. Age at conception (avg. 13.8 months) and first calving (avg. 23.1 months) were not statistically different. Calves fed 4 L colostrum averaged 2.2 lbs/day higher milk production over 2 lactations.

Protein and energy levels for early calf feeding programs – There are a number of calf feeding programs available in the field using whole milk or milk replacers with high quality calf starters. Recent research has demonstrated the importance of protein:energy (P:E) interactions in young milk-fed calves. Protein requirement for maintenance is low and that of energy high. The reverse is true for gain. Feed intake and protein level should be matched to meet the growth needs of calves. This is illustrated in Table 1.

A 20% fat:20% protein milk replacer (MR) is often fed at levels that limit energy intake and growth. At higher intake there may be enough energy for growth but protein limits gain. Cow’s milk is typically 30% fat and 27% protein on a dry matter (DM) basis. Intensive programs are designed for use of higher protein MR (26-28%) with lower fat levels (15-20%). These programs maximize lean gain, enhance skeletal growth and improve feed efficiency. Higher costs are associated with these programs (Table 2). If these advantages can be maintained with good management and nutrition then this investment can be justified by lower health costs, breeding and calving ages. The key is to balance calf nutrient requirements for growth, offer fresh water at all times and stimulate rumen development as economically as possible.

Modified examples of feeding programs were offered in the papers presented at the conference including: 1) Feed 2% of calf birth weight of a 28:20 MR during initial period prior to when calf starter intake is low (2 lbs of MR powder daily for a 100-lb calf). After 7 to 10 days reduce the same MR intake to 1% birth weight to encourage starter intake. Weaning can be determined based on starter intake but allow program flexibility based on calf health, environmental conditions and economic factors; 2) 12 to 14 ounces of a 24:16 MR twice daily in 2 quarts of water (1.6 to 1.85% body weight in dry MR powder/day) for 28 days. Then, once daily to weaning at 35 days as long as calves are healthy. High quality ≥18% calf starter from day 3. Feeding options will depend on each producer’s goals and economic justifications.

If you are interested in obtaining electronic copies of the conference papers cited, feel free to contact me.