Proper Feeding Improves Welfare, Calf Performance and Future Productivity of Dairy Calves16 July 2013
At no extra cost, ensuring adequate nutrition is hugely beneficial in maximising performance and realisation of genetic potential, writes Alex Bach from the Department Ruminant Product at the Catalonian Institute for Advanced Research Studies.
- Adequate nourishment and management early in life not only improve performance, health and welfare of young calves, but also milk production and longevity .
- Attaining improved growth early in life does not represent an extra cost in the total investment in a heifer from birth to first calving, and the benefits are therefore twofold: less health issues early in life (and thus more welfare), and more milk production combined with equal or even lower raising costs.
- Suggested actions are:
- Feed six litres of milk or milk replacer during the first two months of life;
- Provide chopped straw or chopped poor quality hay in addition to a starter;
- Move calves into groups of eight-ten when milk offer is halved (usually one week before weaning completely);
- Group young calves into pens of eight-ten animals based on their previous history of bovine respiratory disease.
In dairy production, as in any other business, a careful allocation of resources and planning is needed to ensure optimal production in the future. Investment in future milk production starts with the selection of an optimal pool of genes for insemination of a dam that will hopefully transfer the desired genetic potential to the offspring. After conception, the genetic potential is set, but nutrition, management and health are key factors in ensuring that this genetic potential is fully expressed later in life.
Unfortunately, care, nourishment and health of dairy replacements heifers are, in many instances, below a level that could be considered adequate. Producers are focused on the lactating animals and usually place young stock as a lower priority. Heifers are usually held in the oldest barn of the enterprise and receive feeds that producers would rather not feed to lactating cows. In addition, new-born calves are separated from the dam and fed on milk replacers or whole milk (either using a bottle and nipple or a bucket) and offered solid feed to promote early weaning. Providing milk or milk replacers to calves is expensive and labour intensive, and producers are therefore usually eager to wean calves as soon as possible and offer a minimum amount of milk or milk replacer.
This case study provides evidence that good nutrition early in life and adequate management not only improve growth, health and welfare of young stock, but also reduce production costs (in the long run), and result in animals that will be more profitable due to improved production ability and increased longevity.
There are specific time windows during development that have long-lasting consequences on the physiological function of the individual. For instance, the pioneering work of McCance (1962) illustrated that limit-feeding rats during the first 21 days of life resulted in a lifetime programming of growth pattern that was lesser than that of rats fed properly. When the dietary restriction was applied for 21 days but at a more advanced age, the intervention had no lasting effect because the underfed rats showed compensatory growth gains when re-fed at normal levels. Likewise, this case study illustrates how early-life nutrition of calves has consequences for the future milk performance of dairy cows.
Welfare Consequences of Improving Nutrient Supply to Young Calves
It is not uncommon to find mortality and morbidity of young calves above ten percent and around 30–50 percent respectively. However, with proper nutrition and management, these figures can be effectively reduced to less than three percent and less than 20 percent respectively. In terms of nutrition, growth (and robustness or resistance to disease) can be improved by providing more nutrients to calves.
Traditionally, producers have been restricting the supply of milk or milk replacer to four litres/day because it is considered expensive. However, four litres/day of milk replacer is, in many situations, insufficient to supply nutrients to ensure adequate immunological function. Thus, an efficient method to reduce morbidity (and improve welfare) is to provide more milk (with an optimum level of six litres/day).
Interestingly, Bach and Ahedo (2008) used a linear programming optimization model and concluded that the entire cost of rearing a heifer (from 0 to 24 months of age) was actually reduced when feeding six rather than four litres/day of milk replacer during the first two months of life. This is because, despite the fact that milk or milk replacer is expensive, the high feed efficiency early in life offsets the apparent increased cost associated with feeding milk replacer. It is true that in the first two months, the nutritional demands of the calf increase, but when calving at similar body weights, heifers that were reared on six litres/day of milk replacer are less expensive to produce than those that received four litres/ day because these had to grow at later stages in life at a lower feed conversion efficiency to reach equivalent body weight.
In terms of management, the stress associated with weaning may compromise welfare and the immune response of calves for at least two weeks after weaning and illness may compromise the growth and welfare of calves. Traditionally, it has been suggested to keep calves isolated for one or two weeks after weaning (to avoid commingling animals when suffering weaning stress). However, no research study has demonstrated that this practice is effective. Conversely, Bach et al. (2010) showed that grouping calves at pre-weaning, when the milk replacer offered was halved, fostered intake of solid feed (Figure 1) and diminished the number of cases of bovine respiratory disease (Figure 2) compared with calves that were kept individually housed. Thus, this management strategy would clearly improve the welfare of young calves.
Group composition at weaning is also important because grouping animals based on the history of respiratory disease will minimize subsequent incidence of the disease. Research has shown (Bach et al., 2011) that by forming a group of animals that have had a previous respiratory case while individually housed will allow the rest of animals to suffer less respiratory illness and improve performance (Figure 3).
Solid Feed Intake Increases When Calves Were Commingled at Pre-Weaning (Milk Replacer Reduced by Half at 49 Days of Age) Compared With Calves Kept Individually
The Number of Respiratory Cases Incurred by Calves Decreases When Calves are Grouped at Pre-Weaning (When Milk Replacer is Reduced by Half at 49 Days Of Age)
Forming Groups of Eight Animals Based on Respiratory History Allows Improvements in Welfare and Health as Well as Performance
Finally, total nutrient intake decreases immediately after weaning and this may potentially expose animals to stress and reduced resistance to infection. The reduction in nutrient intake at weaning can be minimized by weaning based on solid feed consumption or progressively decreasing milk allowance. An effective alternative (due to its relatively low cost) consists of fostering solid feed intake, in addition to the starter feed, by offering chopped (less than 2.5 cm) straw or poor quality hay to calves in a separate bucket. Castells et al. (2012) reported that offering this type of chopped forage increases total solid feed intake compared with calves that are only offered a pelleted starter feed (Figure 4). Improved solid feed intake means more rumination, less non-nutritive oral behaviours, improved health and welfare.
Return on the Investment Needed to Attain Rapid Growth Rates Early In Life
Bach (2011) used a data set containing records from 7 768 Holstein heifers born between 2004 and 2006 that were raised in a contract heifer operation in Spain and returned to their herds of origin (133 herds in total) before calving. Heifers that reached second lactation had a higher daily growth rate (0.8 ± 0.04 kg/day) between 12 and 65 days of age than those that did not (0.7 ± 0.04 kg/day). Thus, not only is the attainment of rapid growth rates early in life more economical because feed efficiency is higher at this time, but the return on the investment is also greater, with improved longevity and welfare benefits.
Total Solids Intake as Affected by Additional Supplementation of Chopped Alfalfa Hay or Chopped Straw (About 2 Cm)
In addition, increased growth early in life has been shown to be associated with improved milk production in the first lactation, as noted by Bach and Ahedo (2008). A study conducted at Spain’s Institute for Food Research and Technology (IRTA), using data from a contract heifer operation, showed that for every 100 g/day additional growth during the first 56 days of life, calves produced an additional 180 kg of milk during the first lactation. Thus, calves following an intensive liquid feeding programme with a growth rate of one kg/ day are likely to produce an additional 900 kg of milk during their first lactation compared with calves reared on a traditional system gaining about 500 g/day.
Finally, as described above, grouping based on disease history reduces the overall incidence of respiratory problems and improves animal welfare. In addition to the economic savings associated with decreased disease, an improvement in cow longevity can also be expected. Bach (2011) has shown that as the number of respiratory cases a calf incurs increases, the number of productive days decreases (Figure 5).
Improving the care of young calves by supplying increased amounts of milk or milk replacer and fostering solid feed intake by providing chopped straw or poor quality chopped grass hay, and grouping animals based on their health records, will not only improve growth rate and reduce morbidity (both of which would result in improve welfare), but will also lead to a less expensive heifer at calving, and an adult animal with improved longevity and increased milking performance.
Relationship Between Number of Respiratory Cases Suffered Before First Calving and Number of Productive Days (Accumulated Days In Milk) of Dairy Cows
Bach, A. 2011. Associations between several aspects of heifer development and dairy cow survivability to second lactation. J. Dairy Sci. 94: 1052–1057.
Bach, A. & Ahedo, J. 2008. Record keeping and economics of dairy heifers. Veterinary Clinics of North America: Food Animal Practice 24: 117–138.
Bach, A., Ahedo, J. & Ferrer, A. 2010. Optimizing weaning strategies of dairy replacement calves. J. Dairy Sci. 93: 413–419.
Bach A., Tejero, C. & Ahedo, J. 2011. Effects of group composition on the incidence of respiratory afflictions in group-housed calves after weaning. J. Dairy Sci. 94: 2001–2006.
Castells, Ll., Bach, A., Araujo, G., Montoro, C. & Terré, M. 2012. Effect of different forage sources on performance and feeding behavior of Holstein calves. J. Dairy Sci. 95: 286–293.