Preweaned heifer management on US dairy operations: Part VI. Factors associated with average daily gain in preweaned dairy heifer calves

Authors: SHIVLEY, CHELSEY - Animal And Plant Health Inspection Service (APHIS); LOMBARD, JASON - Animal And Plant Health Inspection Service (APHIS); URIE, NATALIE - Animal And Plant Health Inspection Service (APHIS); KOPRAL, CHRISTINE - Animal And Plant Health Inspection Service (APHIS); Santin-Duran, Monica; EARLEYWINE, THOMAS - Animal And Plant Health Inspection Service (APHIS); OLSON, JERRY - Zoetis; GARRY, FRANKLYN - Colorado State University

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2018
Publication Date: 5/24/2018
Citation: Shivley, C., Lombard, J., Urie, N., Kopral, C., Santin, M., Earleywine, T., Olson, J., Garry, F. 2018. Preweaned heifer management on US dairy operations: Part VI. Factors associated with average daily gain in preweaned dairy heifer calves. Journal of Dairy Science. 101(10):9245-9258. https://doi.org/10.3168/jds.2017-14022.
DOI: https://doi.org/10.3168/jds.2017-14022

Interpretive Summary: As part of a longitudinal study on the management of dairy heifer calves, 1,410 Holstein heifer calves from 102 operations in 13 states were monitored from birth to weaning. Their growth was measured and average daily gain (ADG) was calculated for the preweaning period. The results showed that ADG of dairy heifer calves during the preweaning period was influenced by many factors, including disease, kilograms of protein fed per day in the liquid diet, milk pasteurization, the interaction between direct-fed microbials and milk pasteurization, temperature and humidity index for the preweaning period, dam lactation, bedding type, the number of calves born (single vs. twin), Cryptosporidium status, and Giardia status. These results highlight the importance of feeding an appropriate quantity and quality of a liquid diet, keeping calves free from disease (Cryptosporidium and Giardia) and comfortable, and mitigating the effects of temperature and humidity during the preweaning period, on ADG. These findings will be useful to other research scientists, veterinarians, and dairy farmers by providing insight into management practices that may improve ADG during the preweaning period.

Technical Abstract: The study objective was to evaluate average daily gain (ADG) in dairy heifer calves based on health, feeding, management practices, and environmental factors. This study included 102 operations in 13 states that participated in the calf component of the National Animal Health Monitoring System’s Dairy 2014 study. This 18-mo longitudinal study included 1,410 Holstein heifer calves monitored from birth to weaning. The mean ADG from birth to final weight was 0.74 kg/d. Backward elimination model selection in Proc Mixed of SAS® after univariate screening (P < 0.2) determined factors that significantly impacted ADG. The final model included dam lactation number, singleton vs. twin birth, bedding type, Giardia and Cryptosporidium fecal shedding, disease events, a categorized average temperature and humidity index (THI) for the preweaning period, amount of protein in the liquid diet (kg/d), milk pasteurization, direct-fed microbials, and the interaction between milk pasteurization and direct-fed microbials. After controlling for other independent variables in the model, calves born to first lactation dams gained less (0.60 kg/d) than calves from second (0.65 kg/d) or third or higher lactation dams (0.64 kg/d). Singleton calves gained 0.07 kg/d more than twins. Calves bedded with sand or no bedding gained less (0.49 kg/d) than all other bedding types. Calves negative for Cryptosporidium or Giardia at the time of sampling gained 0.03 or 0.02 kg/d more, respectively, than calves that were positive for Cryptosporidium or Giardia. Calves with no disease events gained 0.07 kg/d more than calves with one or more disease events. Calves experiencing an average THI less than 50 during the preweaning period gained more (0.67 kg/d) than calves experiencing an average THI from 50 to 69 (0.62 kg/d), or greater than or equal to 70 (0.59 kg/d). Within the range of observed kilograms of protein fed per day in the liquid diet, every additional 0.1 kg of protein fed per day equated to 0.02 kg/d of gain. Calves fed milk replacer with a direct-fed microbial gained less than calves fed milk replacer without a direct-fed microbial and each of the other groups of calves fed pasteurized or unpasteurized milk with or without a direct-fed microbial. These results highlight the importance of feeding an appropriate quantity and quality of a liquid diet, keeping calves free of disease, the type or status of bedding, and mitigating the effects of temperature and humidity on preweaning ADG.