The Milk Producer - July 2010 - (Page 62)

APPLIEDSCIENCE Débora Santschi, Daniel Lefebvre, Roger Cue, Christiane Girard and Doris Pellerin Shorter the better? Although not suited for all herds or all animals, reducing the dry period length can have big benefits for many cows A shorter dry period management strategy could benefit today’s Canadian dairy cows. Research has shown it has no major negative effects on annual milk production, health or reproduction, while providing additional milk at the end of lactation and reducing ketosis incidence in the following lactation. Current recommendations suggesting 60 days as the optimal dry period length are based on research done several years ago. Today’s dairy herds have an increasing proportion of cows that are difficult to dry off and still producing considerable amounts of milk 60 days before calving. Conventional dry period (60 days) Dry-off More recent studies indicate that a 30- to 35-day dry period could be beneficial. It could facilitate transition between lactations without compromising annual milk production. A two-year study involving 850 Holstein cows from 13 commercial herds in Quebec compared the effects of conventional and shorter dry period managements on production, health, metabolism and reproduction. Within each herd, half the cows were managed for a conventional 60day dry period and the other half for a 35-day period. Shortening the dry period to 35 from 60 days also implies modifying the transition feeding program. Cows assigned to the conventional dry period management received a far-off ration from dry-off until 21 days before calving and were then switched to a pre-calving ration until they gave birth. Cows managed for 35 days dry were switched directly to the pre-calving ration for 35 days from the latelactation diet as shown in Figure 1. Rations formulated by each herd’s nutritionist varied among herds. Researchers visited each herd every other week for two years. On each visit, all cows were body condition scored and a keto-test was performed for cows between three and 21 days in milk to detect ketosis. All other information regarding health problems, calving disorders, production and reproduction were collected for subsequent analysis. Production effects Cows managed for a 35-day dry period were milked for an extra month at the end of lactation, yielding an average 530 kilograms more milk per cow. This milk contained 4.4 per cent butterfat and 3.8 per cent protein, representing an additional 23.8 kg of fat and 20.6 kg of protein per cow. Research generally suggests short dry periods might not be optimal for cows ending their first lactation, leading to decreased milk production in the following lactation. In our study, cows that had a short dry period at the end of their first lactations produced 543 kg of extra milk during the additional month of milking. During the following lactation, they produced on average four per cent less milk than cows having a conventional dry period, but this milk had higher fat and protein contents. Latelactation ration Far-off ration Pre-calving ration Earlylactation ration Short dry period (35 days) Dry-off Late-lactation ration Pre-calving ration Earlylactation ration -60 -35 -21 0 Calving Figure 1. Feeding program for a short (35 days) or conventional (60 days) dry period management strategy. 62 | July 2010 | MilkPRODUCER

Table of Contents for the Digital Edition of The Milk Producer - July 2010

The Milk Producer - July 2010
Contents
Editor's Notes
DFO Chair’s Message
Diary Update
DFO
National Policy
DFC Promotion
Thrill of the Grill
Farm Finance
Foundation for Our Future
Agriculture Minister’s Message
General Manger’s Message
Overview
Then and Now:
Notable Quotes:
Grant Smith
Gordon Coukell
Peter Oosterhoff
Vera Mitchell
Bill Simpson
Lew Dunk
Albert Gauthier
Gary Marshall
Stuart Steckle
Tom Kane
Pat McManus
Research
Applied Science
Ruminations
Markets
New’N’Noted
Back Forty

The Milk Producer - July 2010