Monthly Dairy Webinar May 17 to Focus on Heifer Maturity And How It Affects Your Bottom Line

The Iowa State University Extension and Outreach Dairy Team monthly webinar series continues on Wednesday, May 17 from 12 noon to 1 p.m. This program will focus on how heifer maturity affects the dairy’s finance bottom line.

The basic premise under-girding this presentation is that a mature heifer is an animal that has the phenotypic characteristics (e.g. weight and frame) that will allow the full expression of the animal’s genomic productive ability.

Dr. Gavin Staley will share what he sees is the impact of well-known key factors, such as weight and age at calving, as well as average daily gain (ADG) on production.

Breeding heifers earlier has significant advantages, such as lowering heifer inventory and feeding costs. Not surprisingly, there has been a global trend within the industry to breed heifers earlier. However, the caveat to early heifer breeding is that the growth of these animals needs to be increased to meet the new earlier calving age.  The evaluation of a significant number of field records (DC305, 174 herds, representing 456k cows) strongly suggest that improved heifer growth has not occurred in tandem with early heifer breeding.  This has resulted in increasingly immature animals being bred, resulting in long lasting negative productive outcomes in these herds.

His key observations include:

  1. The high correlation between 10-week milk production of Lactation=1 animals and the average annual milk for the entire herd, confirming the predictive value as well as the critical contribution of Lactation=1 performance to overall herd performance;
  2. The relationship between Lactation=1 milk and subsequent lactations;
  3. The impact of first calving age on both lactation 1 and 2.

Staley graduated from the Faculty of Veterinary Science, University of Pretoria, South Africa as a veterinarian in 1984.  After two-year compulsory military service, joined the Faculty of Veterinary Science (Univ. Pretoria) as a lecturer in reproduction.  Completed a M.Med.Vet in Reproduction and qualified as a Veterinary Specialist (Theriogenology).  After six years in academia, joined the largest dairy practice in South Africa in 1993 as a partner, with dairy and equine focus.  Emigrated to the USA in 1998 and joined a dairy practice in Door County, Wisconsin.  While in practice in Wisconsin, he qualified as a Diplomate of the American College of Theriogenologists (2001).  He then relocated to the Central Valley of California in 2003 and has worked in industry for past 19 years in Technical Services positions. Enjoys international travel to learn more about dairying across the globe. Has presented at World Dairy Expo, AABP and various other national and international meetings.

Producers, dairy consultants, and industry reps are encouraged to attend the free webinar live from 12 noon to 1:00 p.m. CDT on May 17 by pre-registering at least one hour before the webinar at:


For more information contact the ISU Extension and Outreach Dairy Field Specialist in your area: in Northwest Iowa, Fred M. Hall, 712-737-4230 or; in Northeast Iowa, Jennifer Bentley, 563-382-2949 or; in East Central Iowa, Larry Tranel, 563-583-6496 or

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