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Dairy notes April 2004

GREENMOUNT CAMPUS HIGH FORAGE HERDS

Rations fed to the Greenmount Campus Herds are assessed on a monthly basis for energy and protein supply.
Problems arose in early February when a vein of low dry matter (16.5%) acidic (<3.5 pH) silage was being fed. The dietary evaluation showed that the cows had an energy deficit of 35 MJ per day. This would have resulted in a daily liveweight loss of 1.3kg. The low silage intake of 7.8 kg of dry matter per day at this stage left little scope to further increase concentrate feeding. An increase in forage intake was required and was achieved through feeding 3.0 kg/day of fermented wholecrop wheat.
 
February

March

Silage intake (kg DM)

7.8

8.4

Wholecrop intake (kg DM)

-

3.0

Concentrate intake (kg DM)

10.3

9.8

Cow liveweight change (kg/day)

-1.3

+0.4

Recognising nutritional problems at an early stage minimises subsequent problems with milk compositional quality, cow fertility and herd health.

Heat detection

To achieve good dairy herd fertility performance, good heat detection is critical. Heat detection efficiency is assessed through calculating first service submission rates for each 3-week period during the breeding season. Submission rates have been improved this winter through a combination of:
  • Lead feeding to minimise early lactation condition score loss.
  • A revised mineral supplementation regime.
  • Using pedometers from the start of the breeding season.
Submission rates

High Forage Herd

Premium Milk Herd

2002-03

69

54

2003-04

86

83

These high submission rates should help tighten up the herd calving patterns next winter.

GET AN INDICATION OF CONCEPTION RATE EARLY IN THE BREEDING SEASON

Results from The Agricultural Research Institute of Northern Ireland, Hillsborough Fertility Study found that the average calving rate to first insemination was 41% (range 18-61%). Estimating the conception rate at an early stage of the breeding season allows prompt action to be taken if necessary.
The absence of a repeat (non- return) for a period of 3 cycles (60-days) gives an early indication of conception rate. Conception rate (%) being the number of non-returns, divided by the number of cows more than 60-days since last service and multiply the outcome by 100. The main disadvantage of this method is that missed heats will mean you are over estimating the number of pregnant cows.
Assume today’s date is 1 April. All cows served up until 31 January (60 days previous) will be included in the calculation. Take a herd where the breeding season started on 1 December. 21 cows were served up until 31 January. 7 had not repeated by 1 April. Conception rate to first service based on a 60-day non-return rate is therefore 33%. The target is around 55%. What is your figure?

WEED CONTROL IN LAST AUTUMNS’ RESEEDS AND GRASS SWARDS

  • Weeds should be controlled early otherwise they reduce tillering and sward productivity.
  • The best response to herbicides is when weeds are in a rapid growth stage and the grass plants have 2 - 3 leaves.
  • Grazing with sheep at high stocking rates when the grass is 10cm tall can control annual tall growing weeds such as Redshank, Charlock and Hempnettle.
  • Other annual weeds which are ground hugging such as chickweed and perennial weeds for example docks and thistles may need to be controlled using herbicides (for example Mecoprop).
  • For all herbicides check that individual products are approved for the use intended and follow the manufacturers label recommendations precisely.

REPAIRING SILOS

Cracked, porous or deteriorated silo floors, walls and collection channels allow effluent to escape easily. Wash and inspect your silos that you intend to use for first cut silage to ensure that they are not leaking. It is important to make effective repairs as soon as possible.
  • The area to be repaired must be thoroughly cleaned.
  • Manufacturer instructions for using sealant must be followed.
  • Joints/cracks must be properly prepared which may involve enlarging the crack to give the recommended slot size for the sealant (for example 95:25 Bitumen).
  • Most sealant requires a primer.
  • Sealing joint and cracks is an ongoing process and must be inspected annually.
Detailed advice on silo repairs can be obtained from locally based DARD Countryside Management staff.

GRAZING MANAGEMENT IN APRIL

Weather permitting, get your cows out for 2-4 hours daily, as soon as possible. In addition to the immediate benefits of cost reduction and improvements in milk yield and quality, early turnout makes it easier to maintain grass quality throughout the spring and early summer. A slow transition to full time grazing during April also allows the cows to gradually adapt to a grass based diet. Target for the first rotation to last until late April. In large herds give preference to the freshly calved higher yielding cows.

Grazing Guidelines

  • Cows should go out with an ‘edge’ to their appetite. Feed the majority of concentrates in the evening if possible.
  • Graze a ‘square area’ not long narrow paddocks as the square paddocks are grazed out better.
  • Use a back fence to ensure that cows are only on an area for one grazing. This minimises sward damage and protects regrowth.
  • In difficult conditions, bring the cows in as soon as they finish grazing. If conditions are really bad they should be kept in the house.
  • Graze the sward to a grass cover of around 1600kg DM/Ha. This ensures good grass utilisation and improves grass quality for the next grazing.

WINTER FORAGE UPDATE

Start planning for your next winters forage requirements now. Have an adequate area of land available to conserve sufficient forage BUT do not limit grass intakes in order to cut additional silage.
Have you considered growing a second forage like wholecrop wheat or forage maize? If all your grass swards are in good condition don’t plough in order to grow a forage crop. Remember these crops become more cost effective in fields eligible for Arable Aid Payments. Grow forage maize and wholecrop wheat where the site, soils and climate are suitable. A high starch level is essential so don’t cut corners on seedbeds, fertilisers and sprays. If you haven’t got the skills, and your land area is limited, consider contracting out to a professional grower.

WATER FOR COWS

Clean water should always be available to the dairy herd. The cow has an acute sense of smell so ensure that all troughs are clean. High production cows need up to 96 litres of water per day especially when eating high dry matter rations and during warm weather.
Large capacity troughs with a fast refill rate should be provided. Remember supplies should be available at milking times during the summertime as well as being strategically placed in the grazing area.
DARD Farm Management Notes for April 2004 have been prepared by Greenmount Campus, College of Agriculture, Food and Rural Enterprise - Tel: 028 9442 6771.