L3 Beef Production

• Liveweight loss over the winter

  Weight loss of up to 10% of autumn(March) liveweight up to 6 weeks before calving has no effect (decrease around 1.5 CS ie 7 to 5.5)
• 500kg cow can weigh 450 kg 6 weeks prior to calving
• One method of avoiding metabolic disorders is to manage cows to lose some liveweight over the autumn early winter period
• Cows being breakfed over winter often lose weight
• Level of energy intake following calving

  About 40 days elapse before the calf can fully utilise the amount of milk the cow can produce, provided the cow has calved in satisfactory condition then for first 40 days following calving no liveweight gain is necessary, switching to a high plane of nutrition 40 days after calving boosts the milk production of the cow and improves the growth rate of the calf, if pre-calving nutrition has been low, and cows calved in less favorable condition then post-calving liveweight gain is important to ensure that cows return to oestrus in time
• A rule of thumb suggested is that cows should be within 5% of their autumn liveweight at the start of mating for satisfactory reconception (CS 6-7)
• What under-nutrition can influence

  • Cow and calf mortality
  • Calf birth weight
  • Time to resume oestrous activity
  • Conception rates
  • Calf weaning weights
  • Metabolic disorders
• Calf mortality rates


  0-13%, 75% in first 3 days, higher in first calvers up to 15%, causes: difficult birth 64%, enteritis 13%, starvation 10%
• Nutrition has to be extreme to influence calf birth weight
• Dystocia


  A delivery requiring more assistance than is necessary, dam factors: pre-calving liveweight, pelvic area, calf factors: sex, birthweight, to reduce dystocia need to control birthweight
• Controlling birthweight


  Nutrition - has to be extreme as dam will buffer, pelvic size - cull small heifers, selection of bull breed, select bulls on EBV for birth weight - below breed average, want bulls with shorter gestation length, select on calving ease direct and maternal
• Effect of calving date and nutrition (pre- and post-calving) on return to oestrus (days)


  July 21-Sept 15 high nutrition 66.7 days, medium nutrition 82.7 days, Sept 9-Oct 10 high nutrition 56.7 days, medium nutrition 62.3 days
• Conception rates


  Cow condition at calving is most important, energy reserves for lactation and then reproduction, seems there is no flushing response in cattle, best to ensure cows are gaining liveweight over mating period (0.3 - 0.5 kg/day) increasing in condition score 6 to 7
• Calf weaning weights


  Poor nutrition before and after calving can depress calf weaning weights by 5 - 10%, cow does buffer against poor feeding by using her own body reserves(if she has any), calves should gain at least 1.00 kg/day while suckling, start to eat grass after 3 weeks and after 12 weeks 50% of intake may be grass, still consuming up to 25- 35% of total intake as milk at 6 months of age, hence get weaning check as they adjust to an all grass diet
• Milk versus Grass


  Relationship between milk and grass intake by calves over time
• Time of Weaning


  Managerial convenience to suit sale dates, fate of calf decides ie sell or keep, early - in drought, normal - sale, late - keep on farm - late calving, very late - up to 12 months for veal - in Victoria this is common, need to consider pasture supplies, yard weaning is sometimes used nowadays
• With poor nutrition beef cows will progressively utilise a high proportion of available pasture, utilise her body reserves and lose weight, delayed onset of oestrus, fail to get pregnant, dry up milk supply, submit to metabolic disorders, then maybe die
• Liveweight problem areas


  • Winter liveweight loss continues up to calving
  • Low liveweight and condition after calving
  • Low liveweight and condition at mating
  • Maximum liveweight achieved too late in the season
• Observe the following features to get an appreciation of past feeding levels: body condition at calving, mating and weaning, length of calving and mating periods, range in size and age of calves, calving and weaning %, mating and calving dates
• Condition Scoring


  Score those areas of the body where accumulation or loss of fat reserves typically occurs, areas to evaluate are the ribs, and tail head, thin cow looks sharp with bones protruding, a fat cow looks smooth and square with bone structure hidden from sight
• Method of Body Condition Scoring

  Assess the level of fat cover on two areas of the animal's body: on the spinous processes of the lumber vertebrae (thin cattle), around the tail head (especially fatter cattle)
• Condition Score Description


  • 1 Emaciated
  • 1.5 Poor
  • 2.0 Thin
  • 2.5 Borderline
  • 3.0 Moderate
  • 3.5 Moderate plus
  • 4.0 Good
  • 4.5 Fat
  • 5.0 Extremely fat
• Angus cow condition score

  • 7 (3.5)
• When to Condition Score

  1. Weaning time - watch young cows

  2. 30 -45 days after weaning - see how feeding is going

  3. 60-90 days prior to calving - last opportunity to get things correct prior to calving

  4. Calving - separate cows on condition

  5. Mating - planning next years production
• BCS Targets


  • Calving BCS 5
  • Weaning BCS 7
  • Mating BCS 6
  • Calving BCS 5
  • Mid winter BCS >4
• Target Seasonal Liveweights and Condition Scores

  • Hard hill country: Weaning 430 kg BCS 7-7.5, Mid Winter 380 kg BCS 4.5-5.5, Pre calving 400 kg BCS 5-5.5, Mating 410 kg BCS 6-6.5
  • Easy hill country: Weaning 470 kg BCS 7-7.5, Mid Winter 420 kg BCS 4.5-5.5, Pre calving 440 kg BCS 5-5.5, Mating 450 kg BCS 6-6.5
  • Good Conditions: Weaning 550 kg BCS 7-7.5, Mid Winter 500 kg BCS 4.5-5.5, Pre calving 520 kg BCS 5-5.5, Mating 530 kg BCS 6-6.5
• Using the BCS buffer

  100 cows that go from BCS 7 to 5 in 100 days need about 25% less feed than 100 cows that started at BCS 5, about 1300 fewer bales of hay, frees up enough pasture to put 0.5 BCS on 800 ewes
• Spring calving cows can lose up to 10% of their autumn liveweight without affecting productivity provided they regain this prior to calving
• The ability to consume large amounts of pasture in the late spring is an asset in controlling surplus and maintaining quality hill country pastures
• There is one nutritional disorder we need to be aware of with our beef cow herds
• Hypomagnesaemia


  A nutritional disorder associated with low levels of Magnesium in the blood, common in pregnant and lactating cows in late winter and spring, beef cows 7-10 days before calving and in early lactation, post drought sporadic losses 30-60 days before calving, when it occurs is high probability of death in extensive beef cattle herds
• Predisposing factors for Hypomagnesaemia


  • Young spring herbage
  • Stress
  • Parturition and Lactation
  • Cow age and parity
  • Abrupt change of Diet
  • Genetics
• Stress as a predisposing factor for Hypomagnesaemia


  Changes in temperature, extreme temperatures, transportation and/or sudden change in environment, undernutrition a critical stress that makes cows susceptible to sudden changes, cows in poor condition post drought are at risk (condition score > 4.0)
• Parturition and Lactation as predisposing factors for Hypomagnesaemia


  These are stressors of their own accord, lactation requires Magnesium, mature cows are predisposed because as cow ages milk production increases as does Magnesium requirement, older cow disadvantaged because Magnesium stored in body(bones) less is available and in less quantity
• Control options for Hypomagnesaemia

  • Well defined mating period so can control feeding
  • Feed consistent levels over late autumn winter to avoid sudden changes in diet
  • Blood testing to assess cow magnesium status particularly after summer autumn diet or during times of feed shortage
  • Feed supplements (hay or silage)
  • Don't run cows on recently fertilised paddocks and if do be prepared to feed Magnesium products
  • Keep stock in sheltered area in winter
  • Post drought supplement with Magnesium earlier than usual 6-8 weeks before calving rather than 2-4 weeks
  • Administer Magnesium products but they are often not suitable for extensive beef cow grazing systems
• Magnesium Supplementation Methods


  • MgO (magnesium Oxide (Causmag) 30 - 60 grams/cow/day via hay or silage
  • Top Dressing magnesium Oxide - Dusting pasture with calcine magnesite (60 mesh) at weekly intervals (500 gram/cow) just prior to grazing will maintain blood Mg levels, apply in morning when dew present
  • Water trough treatment - MgSo4/MgCl2 in water trough, treat water with soluble magnesium salts eg magnesium chloride at rate 60 g/cow/day, introduce to cows slowly as may not be palatable, scours, daily application often impractical, problem in paddocks where there are other water sources
  • Bullets - 40 grams of elemental Magnesium, 1.36 gram/day over 28 days, facilities to administer, costly but effective in extensive systems, maybe deliver to most at risk cows e.g. old cows and those low in CS
  • Licks - not consistently reliable, variable and cyclic licking patterns of cows, 25 - 30 % usually receive nil, use with caution