Longevity and milk production efficiency of Latvian local breeds during last decades.

Abstract

The aim of the study was to analyse the longevity and the amount of energy-corrected milk (ECM) per day of local dairy cattle breeds Latvian Brown (LB) and Latvian Blue (LZ). The study was based on the data of LB genetic resources (LB) 1770 and LZ 921 cows, which were born from January 1, 2000 till December 31 year 2015. Milk productivity and longevity of the LB and LZ cows were analysed by birth year periods: 2000–2005, 2006–2010 and 2011–2015. LZ culled cows lifespan was in average 2,762.8 ± 55.14 days, or 7.6 years and it was significantly higher than for LB. The average lifespan of LB culling cows was 6.7 years. There are cows which had closed 7–12 lactations. On average, cows’ lifespan decreased during analysed period. In general, LZ cows are characterized by higher length of productive life and milking days. LZ cows produced more EC milk during their productive life; however, they had the lower milking day ECM productivity than LB cows.