L2 Beef Cattle

• Consider cow live weight as a proxy for intake
• Increase in efficiency

  • Number of calves weaned
  • Weight of calves weaned
• Requirements for Pregnancy depend on

  • Days from conception
  • Number of offspring in the litter
  • Size of the foetus
• For every 100kg increase in cow liveweight, it requires an additional 11 MJME/day
• Need to ensure larger calves outweigh the cost of extra feed
• An increase in maintenance requirements of 15% from easy to hard hill country
• As liveweight increases so too does maintenance energy requirement, but not in a linear manner
• When animals lose weight, energy is produced by mobilisation of body tissue
• Extra ME required for a change in condition score over the range 4-8 on a 0-10 point scale = 2000 MJ/CS (about 200 kg DM)
• Beef cows can gain liveweight during lactation, with a figure of 60 MJ ME/kg of LWG often used for New Zealand beef cows
• Change in Condition score: One condition score change on the 1-10 scale = 30 kg Live weight
• 1 Kg of liveweight loss in mature cows substitutes for about 30 MJ ME
• Specifications for beef cows in hard and easy hill country

  • Liveweight: 400kg (Hard hill), 550kg (Easy hill)
  • Weight loss/gain: 30
  • Calves born/cow joined: 92 (Hard hill), 97 (Easy hill)
  • Calf birth weight: 30kg (Hard hill), 40kg (Easy hill)
  • Calves weaned/cow joined: 86 (Hard hill), 90 (Easy hill)
  • Calf weaning weight: 175kg (Hard hill), 250kg (Easy hill)
• Body condition score fluctuations of mixed aged beef breeding cows on commercial hill country farms
• Aim to rear 90 cows per 100 bred to weaning
• The cow holds the condition which gets them through the winter
• Maintaining a 365-day calving interval
• Short postpartum anoestrus interval
• Wean calves at a liveweight of 220 kgs
• Maintain a death rate of 2% in the herd
• Make use of the breeding cow to promote and maintain pastures for sheep
• Average cow grows her calves at around 0.8 kg/day from birth to weaning
• Produces 0.3 kg/calf per kg cow liveweight
• High performing cows grow their calves at 1 -1.2 kg/head/day from birth to weaning
• Target calf weaning weight is 45 - 50% of cow live

  weight at weaning
• Stock unit is based on a 55kg ewe with a lamb at foot that eats 550kg of dry matter
• Productivity = Number weaned x weight/

  Number cows mated
• Efficiency = Productivity/

  cow weaning weight
• Ratio = Calf weaning weight/

  Cow weaning weight
• 70% of feed required in a beef system rearing steers to slaughter at 300 kg carcass weight is eaten by the female beef herd
• Increase efficiency by:

  Increasing

  • Number of calves weaned

  • Weight of calves weaned

  Decrease:

  • Maintenance requirements (live weight) of cows
• Beef cow can eat rank pasture with 10 or below MJ and turn it into milk for the calf
• October is the base calving time
• Summer mating of beef cows
• Autumn weaning and culling + getting replacements
• Calve in spring