Heifer Growth Monitoring - Worth the Effort

How accurate is that initial data? It depends on whether the animal was actually weighed as opposed to the frequently used 'eyeball estimation.' The adage, "You can't manage it if you don't measure it," certainly applies to heifer growth.

Growth Monitoring

Monitoring heifer growth, through weight and height, is an important practice for managing the heifer enterprise and the dairy herd overall. It is comparable to collecting milk production data in the milking herd. The most useful data are obtained when growth monitoring is done routinely (monthly, bimonthly), but managers are often discouraged from routine data collection because the practice can be labor intensive, and even dangerous if the handling facilities are not properly designed. However, there are many benefits that can come from collecting the information. If it is impractical to monitor growth on a routine basis, one should consider collecting data when handling heifers for other purposes (breeding, vaccinations, grouping). If all heifers cannot be weighed at a given time, a representative sample should be used to estimate group performance.

Measurement Methods...

Individual heifer weights can be obtained using a weight tape, balance scales, or electronic scales. Weight tapes are very inexpensive, but may provide slightly less accurate individual information. They may also be dangerous to use if animals are not properly restrained. Electronic scales are most accurate, but are also the most expensive option. A measuring stick can be used to measure hip and/or wither heights.

What can this data tell me?

Individual bodyweights can be used to manage heifer movement between groups to maintain uniformity within the group, to decide when heifers are ready to breed, to determine dosage levels when treating animals, and to make culling decisions by identifying poor performers. Collectively, weight and height help determine if desirable growth is being achieved. For example, a longer, taller lean heifer is preferred over one that has simply fattened up with little structural growth. Growth charts are available to compare heifer growth to breed standards. As a rule of thumb, heifers reach puberty at approximately 40 percent of mature bodyweight (MBW). It is recommended to breed them when they reach 54 percent MBW. Heifers should calve with a 7-day postcalving bodyweight at 85 percent MBW. (Van Amburgh, M., and M. Meyer. 2005; Hoffman, P.C. 2007) After measuring weights on individual animals, average daily gains (ADG) should be calculated for the period of time since the last recorded weight and also for the heifer's lifetime as shown below.

Interval Average Daily Gain (IADG) = Current weight - Previous weight

                                                                          # of days in interval

Lifetime Average Daily Gain (LADG) = Current weight - birth weight 

                                                                              Age in Days

Data should be recorded and summarized using dairy management software or a spreadsheet program. The average bodyweight of groups is important information for balancing rations for the heifer herd. Average daily gains for groups indicate whether heifers are performing at, above, or below expectations. Ration adjustments can be more accurately made when this information is available.

Monitoring heifer growth makes sense economically. With today's high feed costs, producers are constantly searching for ways to be more efficient and eliminate waste. Growth data can help with this situation by providing information to better manage the feeding program. It is expensive to feed heifers beyond 24 months of age. Consistently monitoring heifer growth can ensure that the herd is meeting management goals for growth.

Adapted from Virginia Tech Cooperative Extension article titled "Heifer Growth Monitoring - Worth the Effort" by Dave R. Winston, Dairy Extension Scientist. April 2011.