Production efficiency of purebred Holstein and crossbred cows from Viking Red, Montbéliarde and Holstein sires ..

This study aimed to investigate the production efficiency of pure Holstein (Ho) compared to crossbred cows within a 3-way rota- tional crossbreeding scheme involving Viking Red in 1st (F1: VR × Ho), Montbéliarde in 2nd (F2: Mo × F1), and Ho sires in 3rd generation (F3: Ho × F2). Body condition scores (BCS) and body measures were assessed on 635 cows kept in 2 dairy herds. On the same cows, milk yield (MY) was recorded and milk samples were collected to assess the milk composition and individual cheese yield (CY). Body weight (BW) of cows was estimated through regression equations based on BCS and body measures. Net energy requirements were estimated using NRC equations based on predicted BW, MY and milk nutrients. Production indi- cators rely on daily yield (kg/d) of milk, fat, protein, casein, cheese and milk energy (MJ/d) taken as absolute values or scaled on BW, metabolic weight (MW), and total net energy requirements (NE). BCS averaged 3.24, predicted BW 678 kg, and MY 34.5 kg/d, with average 3.77% fat and 3.63% protein. Given an average %CY of 16.80%, cows provided around 5.75 kg/d of cheese. Crossbred cows had (p<.01) greater BCS, BW and total body fat compared to Ho. They yielded lower milk (−5%) with a greater protein content (+1.4%), therefore providing similar daily fat and protein yield. No difference between Ho and crossbreds was found for CY, but greater MY of Ho reflected in greater (5%) daily CY and energy produced in milk. Ho cows were superior to crossbreds also when comparisons were expressed in term of production efficiency indicators for daily yield of milk, milk components, milk energy and CY. However, the magnitude of difference between Ho and crossbreds varied according to the scaling unit considered. Superiority of Ho in comparison to crossbreds ranged between 5 to 9% when production indicators were expressed on BW or MW, with differences always significant (p<.05). Conversely, when production indicators were expressed on NE, differences between genetic lines (p<.05) was limited to 3% for daily CY and MY and to 2% for daily milk energy production, whereas daily yield of fat, protein and casein were not different between Ho and crossbreds. Acknowledgements The research was funded by University of Padova (BIRD 188213/18). Appreciation is expressed to Genesi Project Srl (Castelnovo Sotto, RE, Italy) and ProCross for financial and technical support and to La Corte (ALBALAT Soc. Coop. Agr., Carpi, MO) and Bondioli soc.agr. (Carpenedolo, BS) farms for their precious cooperation