Symposium review: Decomposing efficiency of milk production and maximizing profit

摘要

The dairy industry has focused on maximizing milkyield, as it is believed that this maximizes profit mainlythrough dilution of maintenance costs. Efficiency ofmilk production has received, until recently, considerablyless attention. The most common method to determinebiological efficiency of milk production is feedefficiency (FE), which is defined as the amount of milkproduced relative to the amount of nutrients consumed.Economic efficiency is best measured as income overfeed cost or gross margin obtained from feed investments.Feed efficiency is affected by a myriad of factors,but overall they could be clustered as follows: (1) physiologicalstatus of the cow (e.g., age, state of lactation,health, level of production, environmental conditions),(2) digestive function (e.g., feeding behavior, passagerate, rumen fermentation, rumen and hindgut microbiome),(3) metabolic partitioning (e.g., homeorhesis,insulin sensitivity, hormonal profile), (4) genetics (ultimatelydictating the 2 previous aspects), and (5) nutrition(e.g., ration formulation, nutrient balance). Overthe years, energy requirements for maintenance seemto have progressively increased, but efficiency of overallnutrient use for milk production has also increased dueto dilution of nutrient requirements for maintenance.However, empirical evidence from the literature suggeststhat marginal increases in milk require progressivelygreater marginal increases in nutrient supply.Thus, the dilution of maintenance requirements associatedwith increases in production is partially overcomeby a progressive diminishing marginal biologicalresponse to incremental energy and protein supplies.Because FE follows the law of diminishing returns, andbecause marginal feed costs increase progressively withmilk production, profits associated with improvingmilk yield might, in some cases, be considerably lowerthan expected.