Calf nutrition and health management: Setting the course for future reproductive performance

Transcription

1 Calf nutrition and health management: Setting the course for future reproductive performance Dr. Ken Leslie Visiting Scientist, University of Guelph, Ontario, Canada Proceedings of the Virginia Area Dairy Conferences January 2010 Introduction The cost of rearing replacement heifers is the second largest operating expense on dairy farms. The direct costs of treatment and prevention of disease can be a significant contributor to these costs, and have been estimated at ~US $15 per calf per year for milk fed calves (Kaneene and Hurd, 1990; Miller and Dorn, 1990). Perhaps the most significant and underestimated cost of disease is the long term effects on the health and growth of calves and heifers. Some of the impacts of disease in young calves include decreased growth (Donovan et al., 1998), delayed time to first calving (Correa et al., 1988; Warnick et al., 1994) and increased risk of calving difficulty (Warnick et al., 1994). Studies have also shown that calves treated for respiratory disease (BRD) before 3 months of age are 2.5 times more likely to die after 90 days of age than calves not treated for BRD (Waltner Toews et al., 1986). The extensive economic and welfare costs associated with calf disease are daunting. However, it should be possible to manage and minimize these costs. Implementation of some straightforward preventive measures, as well as early identification of sick animals, can reduce the rate of illness and the number of treatments necessary. Both approaches will reduce the treatment costs and the length of time calves are suffering from respiratory disease (McGuirk, 2008). The long term effects of these diseases should be closely monitored. An easy system for long term monitoring of health and recovery from illness is to chart growth to identify calves with poor performance. This paper and presentation will cover four main areas of calf and heifer management that are integral in the prevention of calf disease, as well as the improvement of growth and performance. It is clear that these factors can have a very positive impact on heifer reproductive performance, and subsequently production, health, and reproduction as lactating animals. These four areas of management are: Colostrum Management Housing Systems Feeding Programs Weaning Strategies

2 Colostrum Management Colostrum management is considered the most important factor associated with the well being of a newborn calf. Studies have identified both short term (Robison et al., 1988) and long term (DeNise et al., 1989) benefits to providing neonatal calves with adequate amounts of high quality colostrum. These benefits include decreased illness and death, as well as increased milk production and growth. Colostrum quality, defined as the concentration of antibodies present in colostrum, is affected by age of cow, breed and season of calving (Donovan et al., 1986). It is useful to measure the antibody content of colostrum to ensure high quality colostrum is being fed to dairy calves. Colostrum quality can be evaluated prior to feeding by hydrometry, refractometry or laboratory methods. Hydrometry using a colostrometer is the most common method currently used. According to a US survey in 2007, 43.7% of US dairy operations have used a colostrometer to measure the immunoglobulin (IgG) content of colostrum. It is a fast, easy method for use on farm. However, the colostrometer has issues related to the fragility of the instrument and is subject to errors associated with the temperature of colostrum. Recently, a new digital BRIX refractometer has been found to be useful on farm. This method requires a small amount of colostrum for testing, is not temperature sensitive, and is more user friendly and reliable. Some important points involving the quality of colostrum, the quantity fed, the quickness it is delivered, the cleanliness maintained and some other factors are shown below, including a specific checklist of items to watch: QUALITY : Only feed non mastitic colostrum that is not visibly watery, discoloured or bloody. Avoid feeding colostrum (and milk) from Johne s positive or suspect cows. The relationship between IgG conc and volume of colostrum is unpredictable. Vaccination of cows 3 6 wks prior to calving increases passive transfer of antibodies. Cows with a dry period <21 days may have significantly lower IgG concentrations. Quality decreases quickly after calving. Collection should occur within 1 to 2 hours, max of 6 hrs. QUANTITY: 4 quarts (10 12% of body weight), by esophageal feeder if necessary. Feed at least 2 quarts more of colostrum within the next 12 20hrs, resulting in 6 quarts within 24hrs of birth. Allowing calves to suckle the cow has been shown to result in inadequate volumes being consumed. QUICKNESS: Within 4 hours of birth, max of 6 hrs. (Remember: 4 quarts in 4hrs)

3 A calf s ability to absorb colostrum declines quickly after 6hrs and is accelerated by the consumption of even small volumes, and by bacterial contamination. Feeding a small volume early will actually reduce later absorption. CLEANLINESS: Bacterial contamination commonly reduces passive transfer of IgG. To avoid contaminated colostrum, properly prep the udder, don t pool raw colostrum and discard colostrum from mastitis infected cows. Most colostrum contamination occurs after it leaves the cow. So, properly sanitize all milking, storage & feeding equipment. Replace worn or damaged equipment (e.g. esophageal feeders). Colostrum should be fed right away, or refrigerated/frozen within 1hr. Unpasteurized colostrum should only be stored for 2 days in a refrigerator. Frozen colostrum can be kept for 1 year. Other: ALL calves should be removed from the cow within 1 2hrs to prevent the first meal being manure. If commercial colostrum replacement is used because of short supply or disease management, be sure it provides g IgG (usually packages) and a nutritional source of protein & energy. Checklist for Colostrum Management Collect colostrum within 1 2 hours after calving. Clean and prep the cow s udder. Sanitize all milking, storage & feeding equipment. Feed 4 Quarts of colostrum in 4 hours (by esophageal feeder if necessary). Feed at least 2 quarts more colostrum within 12 20hrs. Don t feed colostrum that is visibly mastitic, discoloured, watery, or bloody. Avoid feeding colostrum (and milk) from Johne s positive or suspect cows. Remove calves from the maternity pen within 1 2 hours of birth Housing Systems Dairy producers are generally willing to take the necessary steps to prevent disease through management changes. However, there is a general lack of guidelines and direction for the appropriate changes to be made. The importance of minimizing stress in order to prevent immune suppression is clear, but the practical methods to achieve this goal are not obvious. Certainly, the use of calf hutches, super hutches, and properly ventilated calf barns has been greatly helpful. Yet, transitioning calves from being milkfed to weaned heifers remains a formidable challenge. Some dairy producers are attempting to minimize post weaning stress by removing dividers between individual

4 stalls in nursery barns to form groups prior to movement to the heifer rearing barn. From economic and labor standpoints, most nursery barns are not designed to house weaned calves for extended periods of time. Thus, in order to adopt this practice, producers have to make important decisions with limited information. Currently, the benefits of grouping calves in the nursery 1 week prior to movement to a new facility are being investigated. However, this is only the first step towards creating practical guidelines for producers. Factors such as the effective group size and the timing as to when calves should be grouped are unknown. Of equal importance is identifying simple indicators for detecting calves that fail to adapt to their new environments, and are at risk for the development of disease. Some important points involving housing and management factors are shown below, including a specific checklist of items to watch: In cold weather, provide ample straw bedding so calves can nest deeply (i.e. legs hidden when lying). Always provide enough bedding so that calves are clean and dry. You should be able to kneel in the pen without your knees getting wet. Calves don t make enough heat for negative pressure ventilation systems (i.e. naturally ventilated). If air quality is a problem in your calf barn, consider a positivepressure system (e.g. fans & tube ducts). Checklist for Housing Systems Keep calf pens clean and dry. In cold weather, bed calves with enough straw for them to nest deeply. Feeding Programs Historically, conventional milk feeding to dairy calves has provided 10% of body weight of whole milk or milk replacer, usually distributed over two meals per day, fed either by bottle or bucket. However, it is clear that calves will consume milk at greater than 20% of their body weight, if given free access to milk. Research on such systems has shown greatly increased body weight (Appleby et al., 2001; Jasper and Weary, 2002; Khan et al., 2007), and reduced behavioural signs of hunger (De Paula, Vieira et al., 2008; Borderas et al., 2009). Furthermore, these studies have produced no negative health impacts, and perhaps even health benefits (Appleby et al., 2001; Khan et al., 2007; Borderas et al., 2009). However, until recently, the only system for safely providing freeaccess to milk replacer has been through the use of automated calf feeders, that mix the replacer on demand by the calf. The concern with offering pre made replacer on freeaccess basis is with excessive bacterial contamination.

5 Recently, a system of implementing free access acidified milk feeding has been developed and has gained substantial adoption in Canada (Anderson, 2008). However, little controlled research has been conducted on this feeding system on calf performance and other effects. In the end, an important goal for calf feeding programs is to have calves double their birth weight and grow 4 5 inches in height by weaning. Some important points involving calf feeding programs are shown below, including a specific checklist of items to watch: Conventional feeding of 4 quarts of milk/day rarely provides adequate nutrition for a growing calf. Some experts advocate feeding volumes of milk up to 20% of calves weight (8 10 quarts/day). Increase volume of milk fed by 2 pints for every 10⁰F drop in ambient temperature, starting at ~40⁰F. If a 20:20 milk replacer is fed, on average, calves will need 1 quart more than if it was whole milk. Not all milk replacers are created equal. They vary in protein & fat content. It may be worthwhile to investigate your calf feeding practices & comparing to the NRC Nutrient Requirements of Dairy Cattle. Feed high quality calf starter after 4 days of age. Start with small handfuls. Keep it fresh. Hay should be fed only after weaning as it may slow rumen development in preweaned calves. Water should be available at all times, especially in hot weather. Calves will eat more and grow better. Checklist for Calf Feeding Programs Calves should double their birth weight and grow 4 5 inches by weaning. Calves can be fed up to 20% of their weight (8 10 quarts/day). Increase volume of milk fed by 2 pints for every 10⁰F drop, starting at ~40⁰F. If 20:20 milk replacer is fed, calves need 1 quart more than if it was whole milk. Feed calf starter after 4 days of age. Start with small handfuls. Keep it fresh. Hay should be fed only after weaning. Water should be available at all times. Weaning Strategies The importance of successful weaning has been described above, under housing systems. Some important points involving weaning strategies are shown below:

6 Calves can be weaned if they consistently consume 1kg of starter daily. After weaning, calves should be kept in the same housing for 1 week to reduce stress. Resources for more information include: Questions can be directed to Ken Leslie at keleslie@ovc.uoguelph.ca References Anderson, N Free access feeding of acidified milk: Setting up the system using formic acid. Appleby, M.C., D.M. Weary and B. Chua Performance and feeding behaviour of calves on ad libitum milk from artificial teats. Appl. Anim. Behav. Sci. 74: Borderas,T.F., A.M.B. de Passille and J. Rushen Feeding behavior of calves fed small or large amounts of milk. J. Dairy Sci. 92: Correa MT, Curtis CR, Erb HN and White ME (1988). Effect of calfhood morbidity on age at first calving in New York Holstein herd. Preventative Veterinary Medicine 6: DeNise SK, Robison JD, Stott GH, Armstrong DV Effects of passive immunity on subsequent production in dairy heifers. J. Dairy Sci. 72: De Paula, Vieira, A., V. Guesdon, A.M. de Passillé, M.A.G. von Keyserlingk and D.M. Weary, Behavioural indicators of hunger in dairy calves. Appl. Anim. Behav. Sci. 109: Donovan GA, Dohoo IR, Montgomery DM and Bennet FL (1998). Calf and disease factors affecting growth in female Holstein calves in Florida, USA. Preventative Veterinary Medicine 33: Donovan, G.A., L. Badinga,, R.J. Collier, C.J. Wilcox, and R.K. Braun Factors influencing passive transfer in dairy calves. J. Dairy Sci. 69:

7 Jasper, J. and D.M. Weary Effects of ad libitum milk intake on dairy calves. J. DairySci. 85: Kaneene JB and Hurd S (1990). The national animal health monitoring system in Michigan. III. Cost estimates of selected dairy cattle diseases. Preventive Veterinary Medicine 8: Khan, M.A., H.J. Lee, W.S. Lee, H.S. Kim, S.B. Kim, K.S. Ki, J.K. Ha, H.G. Lee and Y.J. Choi Pre and postweaning performance of Holstein female calves fed milk through step down and conventional methods. J. Dairy Sci. 90: McGuirk SM (2008). Disease management of dairy calves and heifers. Veterinary Clinics of North America: Food Animal Practice 24: Miller GY and Dorn CR (1990). Costs of dairy cattle diseases to producers in Ohio. Preventive Veterinary Medicine 8: Robison, J.D., G.H. Stott, and S.K. DeNise Effects of passive immunity on growth and survival in the dairy heifer. J. Dairy Sci. 71: Stanton AL, LeBlanc SJ, Dingwell RT, Kelton DF, Millman ST, Wormuth J and Leslie KE (2008). An evaluation of tulathromycin treatment at post weaning movement on the incidence of respiratory disease and on growth in commercial dairy calves. Waltner Toews D, Martin SW and Meek AH (1986). The effect to early calfhood disease on survivorship and age at first calving. Canadian Journal of Veterinary Research 50: Warnick LD, Erb HN and White ME (1994). The association of calfhood morbidity with firstlactation calving age and dystocia in New York Holstein herds. Kenya Veterinarian. 18: