Abstract #W58
Section: Lactation Biology (posters)
Session: Lactation Biology 1
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: Lactation Biology 1
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# W58
Correlations of feed efficiency measures to parameters of the Dijkstra lactation model in dairy cattle.
D. J. Seymour*1,2, A. Cánovas2, T. C. S. Chud2, J. P. Cant1, V. R. Osborne1, F. S. Schenkel2, D. Hailemariam3, E. E. Connor4, J. E. Pryce5,6, E. Wall7, S. Wegmann8, J. Lassen9, F. Miglior2, 1Centre for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 2Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 3Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, AB, Canada, 4Animal Genomics & Improvement Laboratory, USDA ARS, Beltsville, MD, 5Agriculture Victoria, Agribio, Centre for AgriBioscience, Bundoora, VIC, Australia, 6School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia, 7Animal & Veterinary Sciences, Scotland’s Rural College, Edinburgh, UK, 8Qualities AG, Zug, Switzerland, 9Viking Genetics, Randers, Denmark.
Key Words: dairy cattle, feed efficiency, lactation curve
Correlations of feed efficiency measures to parameters of the Dijkstra lactation model in dairy cattle.
D. J. Seymour*1,2, A. Cánovas2, T. C. S. Chud2, J. P. Cant1, V. R. Osborne1, F. S. Schenkel2, D. Hailemariam3, E. E. Connor4, J. E. Pryce5,6, E. Wall7, S. Wegmann8, J. Lassen9, F. Miglior2, 1Centre for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 2Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 3Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, AB, Canada, 4Animal Genomics & Improvement Laboratory, USDA ARS, Beltsville, MD, 5Agriculture Victoria, Agribio, Centre for AgriBioscience, Bundoora, VIC, Australia, 6School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia, 7Animal & Veterinary Sciences, Scotland’s Rural College, Edinburgh, UK, 8Qualities AG, Zug, Switzerland, 9Viking Genetics, Randers, Denmark.
There is currently a renewed interest in assessing feed efficiency in dairy cattle, predominantly in the field of animal breeding. As feed efficiency is directly related to milk yield, it is possible that different aspects of an animal’s lactation curve could be indicative of whether an animal is more or less feed efficient. Feed efficiency estimates can also be inflated before peak milk yield due to negative energy balance. The objective of this study was to evaluate the relationship between measures of post-peak lactation feed efficiency and parameter estimates of the Dijkstra lactation curve model. Data pertaining to calving, dry matter intake, milk yield and milk composition were obtained from a total of 1,933 cows from the Efficient Dairy Genome Project database, spanning 6 different research herds and 15 years. The Dijkstra model was fit to individual multiparous lactations up to 305 d in milk, estimating parameters for initial milk yield (M0), days to peak yield (Tp), peak milk yield (Mp), cell proliferation at parturition (uT), exponential decay (k), and rate of mammary cell death per day (L; lactation persistency). Feed efficiency (gross feed efficiency [GFE], average return over feed costs [ROFC], and residual feed intake [RFI]) were calculated for the period after peak milk yield for each lactation where model parameters were successfully estimated (n = 1,004). GFE and RFI were associated with M0 (r = −0.084; P < 0.01) and Tp (r = 0.068; P = 0.04), respectively. ROFC was correlated (P < 0.001) with M0 (r = 0.217), Mp (r = 0.615) and L (r = −0.174). All measures were associated (P = 0.05) with k (GFE: r = 0.061; ROFC: r = 0.113; RFI: r = −0.097). These results suggest that while improved return over feed cost is associated with improved persistency of lactation and increases in both initial milk yield and peak milk yield, other aspects of the lactation curve are generally unrelated to feed efficiency after peak production in multiparous cattle. Further investigation with a more robust measure of feed efficiency is warranted.
Key Words: dairy cattle, feed efficiency, lactation curve
