Dairy notes December 06

• Silage dry matter changes during the winter and must be checked regularly
• Remember the silo is filled with grass from different fields over a 24-48 hour period and due to the very warm weather during the summer silage dry matter increased rapidly.
• Intakes - To ensure your cows aren’t being underfed check silage intakes and dry-matter.  As you move up the pit it is likely that the silage will be from fields which weren’t wilted for as long as the last fields ensiled – this year that could mean a large difference in dry matter content. Also the dry-matter of silage fed from an open silo pit after several days’ rain could drop by 4-5 percent.  
• The difference between feeding 40 KG of a 25 percent dry-matter 11.3 ME silage and 40 KG of a 30 percent dry-matter sample of similar energy content is over 22 MJ of energy.
• This equates to almost 2 KG of concentrates, 0.8 KG /day of weight loss, or 4 litres of milk.
• Monitor total feed intake on a regular basis to ensure that planned winter feeding targets are being met.
• In the absence of a weighbridge, the weight of silage used can be measured by measuring the volumes of silage blocks taken from the silo.  
• In combination with silage density these figures can then be used to determine the amount of silage eaten by the herd.  
• The intake figures, and the silage analysis report can then be used to calculate an energy balance for the herd to determine if cows are being adequately fed.  
• If you require help your local DARD Dairying Development Adviser can assist in developing a feed plan for your herd.  
• Forage Maize - Early December normally sees the introduction of forage maize into the cow’s diet. It has a very different protein content and mineral profile to grass silage.  Rations need to be adjusted so it is important to remember the following:
• Analysis is the starting point for any ration formulation.
• Higher protein blends will be required to balance the diet (22 - 28%).
• The mineral/vitamin content needs to be adjusted.

• Keep a clean, smooth silo face during the feed out period
• Remove silage by working across the silo face as quickly as possible
• Avoid loose silage lying around the silo floor
• Remove all visibly mouldy silage as this can harbour mycotoxins which will reduce performance.
• Clean feed troughs thoroughly at least once a week

• Control cow condition aiming to calve down at condition score 3.0.  Overfat cows are at greater risk.
• Provide at least 40 percent forage in the diet on a dry matter basis.
• Offer some long forage (hay or straw) to encourage cudding
• Avoid feeding more than 4 KG of high starch concentrates in any one feed.  
• Introduce a mid-day feed.
• Ensure the overall crude protein content of the diet does not exceed 17-18 percent
• Avoid sudden diet changes.  Increase meal feeding levels gradually for fresh calvers.
• Use a zinc based footbath regularly to harden hooves
• Including a buffering agent in the concentrate can help reduce rumen acidity.
• Feed a high digestible fibre concentrate i.e. one containing sugar beet, citrus, soya hulls or malt sprouts.

• Cows must be clearly identified, preferably by freeze branding
• List cows in order of calving date.  Making it easier to prepare action lists by identifying cows
• Record cows which were in heat three weeks previously and are potentially due on heat again
• Identify problem cows which are not cycling or repeat breeding requiring veterinary attention
• Ideally this should be used in conjunction with a 21day pocket breeding diary providing an on hand record of all heats and services

• Adequately fed (including minerals and vitamins) to avoid excessive loss of body condition after calving.
• In good general health and vaccinated against infectious diseases, with minimal levels of lameness.
• Suitably housed with a spacious loafing area and a solid non-slip surface to encourage mounting activity.
• In close proximity to a penned bull.

• Tail painting, pressure strips (for example, Kamar or bovine beacons which are glued onto the tail head) or electronic mount detectors, all indicate if the cow has been mounted and may be in heat.
• Pedometers - these devices are attached to the cow’s leg to monitor activity. Increased activity indicates that the cow may be in heat.
• Teaser bull - vasectomised bulls, incapable of breeding, have proved very successful. They should be fitted with a chin ball marker (these are also very useful for breeding bulls).  It is important to remember that Teaser bulls have all of the aggression associated with fertile bulls and should be treated accordingly.

• When selecting sires on milk yield, select in relation to the production system. Will repeated selection for high milk yields mean you have to adopt major changes in feeding arrangements and other management factors.
• Compositional quality is an important issue in Northern Ireland where 85+ percent of the milk is processed. Aim to improve the genetic potential for both butterfat and protein.
• Good functional conformation is very important and, in particular breeding for good udder, legs and feet is a priority.
• £PIN and Profitable Life Index (£PLI) are useful indicators of the predicted financial performance improvements. £PIN is expressed in pounds and takes into such factors as milk volume, butterfat and protein values, and the costs of feed, leasing and transport.  In contrast £PLI combines not only production but also longevity traits.  Milk yield has the main influence on these two indices.
• If your herd has a high somatic cell count avoid those sires with a PTA for SCC of above +10 percent.
• Reliability indicates the confidence that can be given to a PTA. In general only use bulls with a reliability of 75 percent or greater.
• Avoid close inbreeding unless the reasons for doing so are fully considered. A number of AI companies offer a computerised mating service that will help to identify when this occurs.