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Herdlife Lactation Yield, Herdlife, and Survival of Holstein and Ayrshire-Based Lines of Dairy Cattle

Research Branch, Agriculture Canada, Ottawa, Ontario, Canada K1A 0C6

ABSTRACT

Length of herdlife, lifetime milk and component yields, daily milk and component yields, and survival rates were assessed from multiple lactation records of 927 cows in a Holstein line and an Ayrshire-based synthetic line. Holstein cows were progeny of random matings to either Holstein untested sires or progeny-tested Canadian and American Holstein sires. Ayrshire cows were randomly mated to Ayrshire untested sires or Canadian and American Ayrshire, Finnish Ayrshire, Norwegian Red, or Brown Swiss progeny-tested sires to produce the foundation females in the Ayrshire-based synthetic line.

The Holstein cattle produced more milk and protein per day of milking herdlife or total herdlife than cows in the Ayrshire-based line and proportionately more survived to initiate second lactations. Daughters of the progeny-tested American and Canadian Holstein sires had significantly higher lifetime and daily milk, protein, and fat yields than daughters of young untested Holstein sires whereas lifetime yields of daughters of untested and progeny-tested Ayrshire sires were equivalent.

² Animal Research Centre, Ottawa, Ontario K1A 0C6.

³ Animal Production Division, Agriculture Canada, Ottawa, Ontario K1A 0C6.

⁴ Lennoxville Research Station, Lennoxville, Quebec J1M 1Z3.

⁵ Lethbridge Research Station, Lethbridge, Alberta T1J 4B1.

⁶ Experimental Farm, Normandin, Quebec G0W 2E0.

⁷ Charlottetown Research Station, Prince Edward Island C1A 7M5.