Balancing Milk Levels in Beef Herds

By Jane Parish, Extension Beef specialist, Mississippi State University

One of the challenges in beef cattle selection and culling involves finding the optimum level of milk production for the herd.  Optimum does not necessarily mean maximum.  Too much milk production in a herd can have some negative consequences.  Likewise, too little milk can result in lighter weaning calves.  The level of milk production in a cow-calf herd must fit the forage and feed environment to ensure that nutrient requirements of lactating cattle are met and rebreeding is not hindered by inadequate nutrition.

Nutritional and other environmental factors will affect the degree to which genetic potential for milk production is expressed.  Even when the genetic potential for a particular level of production is present within an individual or herd, it does not mean that this level of milk production will be achieved.   Both genetic and environmental influences on milk production can ultimately affect calf weaning weights and cow reproductive rates.

Performance Tradeoffs

There are genetic antagonisms present in beef production where improvement for one trait tends to decrease the level of performance in another trait.  Milk production is no exception to such performance tradeoffs.  As milk production increases, more energy, protein, and other nutrients are leaving the beef female and being transferred to the suckling calf through the milk.   This benefits the calf but also increases the dam’s nutrient requirements.   If these increased nutritional needs are not met, then the lactating cow or heifer may loose body condition.  In turn, reproductive rates can be negatively impacted if body condition drops below moderate levels.

As cow body size increases, larger quantities of nutrients are required.   A higher milking cow, on the other hand, requires a diet that is higher in both quantity and quality.  Because high-milking beef females often cannot consume enough extra low-quality forage and feed to meet added nutrient demands, high genetic milking potential may not match up well to a low quality diet.   Of course, increased nutritional demands resulting from high milk production or larger body size can be met with a proper feeding program, but expenditures for feed and pasture must increase to meet these demands.  Optimizing milk production level with nutritional program costs is a balancing act.

As nutrient costs increase, high milking or larger cattle may be less desirable in a cow-calf operation.  In contrast, reasonably priced feed favors heavier calves from higher milking dams in cow-calf production and lighter-weight calves fed over a longer period in the feedlot.  Increasing milk yield has been shown to increase both weaning weights and efficiency to weaning in the cow-calf sector, with mixed results on efficiency to slaughter.   Therefore, for cow-calf producers who sell their calves at weaning, increasing milk and size may be practical for increasing weaning weights and optimizing production when feed prices are reasonable.  However, for producers retaining ownership of calves through post-weaning phases, maximizing profit by increasing weaning weights via milk production works in some cases and not in others.

Genetic potential for milk production can vary widely among cattle.  An efficient level of milk production and mature body size for the herd may vary from one farm to the next.  A moderate level of milk production is generally most appropriate.  However, low or high milk production levels may be applicable, depending on production and market conditions.   In general, larger body size is more suitable with larger quantities of forage, and higher milk genetics fit better with adequate levels of high quality forage.

Selection Considerations

Selection tools are available that provide information on the genetic potential of individual animals for specific traits, such as milk production.  Expected progeny differences (EPDs) give an indication of the expected performance of an animal’s calves for a particular trait.  Milk is an important maternal trait that directly affects calf weaning weights, and milk EPDs are one of the more common EPDs available from breed associations.  Milk EPDs are expressed as pounds of calf weaned due to the milk production of the dam, not as pounds of milk produced.

Another important selection consideration related to milk production is evaluation of udder structural soundness.  A cow should have a healthy, well-suspended udder with a level floor and four proportionally sized teats.  Calves can have a difficult time nursing pendulous udders or balloon teats, which can cause weaning weights to suffer.

As with many other traits, selection for milking ability involves assessing production resources and determining what works best for the production and marketing environment.   Selection decisions should focus on finding an acceptable balance among milk production and other economically important traits.  There is no one right answer that will every cow-calf operation, but there may be opportunities for improving production efficiency through informed cattle selection and culling decisions within individual herds.