Application of a Bio-Economic Model to Demonstrate the Importance of Health Traits in Herd Management of Lithuanian Dairy Breeds

Abstract

Assessing the economic importance of traits is crucial for delivering appropriate breeding goals in dairy cattle breeding. The aim of the present study was to calculate economic values (EV) and assign the importance of health traits for three dairy cattle breeds: Lithuanian Black-and-White open population (LBW), Lithuanian Red open population (LR) and Lithuanian Red old genotype (LROG). The EV estimation was carried out using a stochastic bio-economic model SimHerd, which allows the simulation of the expected monetary gain of dairy herds. The simulation model was calibrated for LBW, LR and LROG breeds, taking into account breed-specific phenotypic and economic data. For each trait, two scenarios were simulated with a respective trait at different phenotypic levels. To obtain the EVs, the scenarios were compared with each other in terms of their economic outcomes. In order to avoid the double counting of the effects, the output results were corrected using a multiple regression analysis with mediator variables. The EVs were derived for the traits related to production ECM (energy-corrected milk), fertility, calving traits, calf survival, cow survival and direct health. To demonstrate the importance of health traits in herd management, we provided reliable EVs estimates for functional traits related to herd health. The highest EV for direct health traits, caused by an increase in of 1 percentage point, were those found for mastitis (EUR 1.73 to EUR 1.82 per cow-year) and lameness (EUR 1.07 to EUR 1.27 per cow-year). The total costs per case of ketosis, milk fever and metritis ranged from EUR 1.01 to EUR 1.30, EUR 1.14 to EUR 1.26 and EUR 0.95 to EUR 1.0, respectively. The highest economic values of dystocia were estimated for LROG (EUR −1.32), slightly lower for LBW (EUR −1.31) and LR (EUR −1.23). The results of this study show the importance of health traits to the economic features of cattle herd selection of new breeding goal and this would improve the herd health. The economic evaluation of the functional traits analyzed in this study indicated the significant economic importance of the functional traits in Lithuanian dairy cattle breeds.

Genetic Variability and Conservation Challenges in Lithuanian Dairy Cattle Populations

“…Other authors have also highlighted additional significant differences of morphological traits between the breeds [34,35]. A previous study [36], in which the economic values (EVs) of functional traits for the three Lithuanian dairy cattle breeds were derived, indicated that the economic values of energy corrected milk (ECM) were 0.16 €/kg for Lithuanian Black-and-White open population (LBW) and Lithuanian Red open population (LR) and 0.21€/kg for Lithuanian Red old genotype (LROG). The higher EV for LROG was caused by a lower feed intake and a lower milk yield, compared with LR and LBW, as it was assumed that a larger proportion of concentrated feed was needed to ensure the increased milk yield [36].…”

“…A previous study [36], in which the economic values (EVs) of functional traits for the three Lithuanian dairy cattle breeds were derived, indicated that the economic values of energy corrected milk (ECM) were 0.16 €/kg for Lithuanian Black-and-White open population (LBW) and Lithuanian Red open population (LR) and 0.21€/kg for Lithuanian Red old genotype (LROG). The higher EV for LROG was caused by a lower feed intake and a lower milk yield, compared with LR and LBW, as it was assumed that a larger proportion of concentrated feed was needed to ensure the increased milk yield [36]. In practice, environmental and economic factors, such as poor housing system, inadequate feeding, heat stress and low milk prices, play a key role in the survival of the herd and influence the length of the productive life of cows [37,38].…”

Grounding the economic selection index for evaluation and selection of dairy cattle

“…Evaluation and selection by selection indexes is an important tool in dairy cattle breeding, as it allows combine information on several traits into a single value, which is used to make selection decisions (Mancin et al, 2022;Marašinskienė et al, 2022). The ideal breeding goal for dairy cat-tle remains the main topic of researches, although consensus on this issue is problematic and is intensively discussed in the scientific literature (Miglior et al, 2017;Cole and VanRaden, 2017;Cole et al, 2021).…”