Although we’re aware of the importance good management over the next three to four months has on next season’s production, working out the optimal time to dry off can be far more challenging. This month’s article discusses some practical considerations to consider when deciding on when to dry off.
Assessing condition scores (CS) of your herd now is an important first step to making informed decisions. Target condition scores are 5 to 5.5 for mature cows and 5.5 for first calvers. Dairy NZ run workshops on condition scoring, and have a good booklet available on their website.
Good management of pasture, supplements and condition scores in mid to late lactation is important to extending lactations and drying cows off close to target condition scores at calving. The former should increase farm profitability at current milk solids prices, and the latter by saving feed during the dry period. The Dairy NZ table below demonstrates cows in poor condition need to be dried of early and require more and higher quality feed to achieve target calving condition scores, resulting in shorter lactations and higher feed costs relative to production.
Table 1: Dry-off time based on body condition score and time to calving
|BCS||BCS||Days cows need to be dried off before calving||Days cows need to be dried off before calving|
|Cow||Rising 2-3 year olds||Autumn pasture||Autumn pasture + supplement fed above maintenance|
The importance of feed quality to gain condition, was demonstrated in a recent study where dry cows required an additional 210 kg DM of autumn pasture on top of maintenance to gain one BCS, but only 125-150 kg of DM of a good quality supplement.
High starch or sugar and low protein feeds like cereal grains, maize or whole crop silages tend to work best when targeting condition gain. Mineral supplements containing selenium and zinc may also be beneficial, as these are essential components in the formation of keratin plugs and in udder regeneration.
Most trace mineral supplements also contain the other key trace minerals, cobalt, copper and iodine. Balancer mixes containing the key major minerals should be fed if supplementary feeds contribute a significant part of the diet, as they tend to be low in all minerals. Using a feed ration program can help determine the most appropriate products to feed.
As featured in NZ Dairy Farmer