1. Growth and efficiency of feedlot cattle
Prof Eddie Webb
Head: Dept. Animal & Wildlife Sciences
University of Pretoria
2015 Cattleman's Conference, SA Feedlot Association

2. 2015 Cattleman's Conference, SA Feedlot Association
Index
Why focus on growth and efficiency?
Local demand
Options to increase meat production from gate to plate
Animal growth and development?
Efficiency and estimates of Growth?
Does size matter?
From veld to efficient feedlot growth
Old and new technologies to improve growth and efficiency
Growth enhancing technologies
Selection for ADG, FCR (F:G), RFI
Genomic technologies
Ultrasound scanning & Metabolic hormones
Options for improving feedlot performance
2015 Cattleman's Conference, SA Feedlot Association

3. 1. Why focus on animal growth and efficiency?
Only increase profitability through reductions in input costs
Improving growth and efficiency
Improve value of product
2015 Cattleman's Conference, SA Feedlot Association

4. 1(a).Local demand for meat
Beef consumption increased more than beef production for the period from
Local beef industry needs to increase beef production by about 11% per annum to supply the demand
Red meat production increased. Carcass weights increased from 230 kg to 262kg
SA has capacity to increase meat production – without changing the nature of the production systems
2015 Cattleman's Conference, SA Feedlot Association

5. 1(b).Options to increase global meat production?
Horizontal integration
Deforestation
CO2 utilization and O2 production
2. Vertical integration
More efficient production
Reproductive efficiency
ADG’s, FCE’s
Feed quality
Strategic supplementation
Link systems (veld, feedlot)
Add value
2015 Cattleman's Conference, SA Feedlot Association

6. 1(c).Effective growth from gate to plate?
2015 Cattleman's Conference, SA Feedlot Association

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2. Understanding animal growth and efficiency is essential to optimize production efficiency
2015 Cattleman's Conference, SA Feedlot Association

8. 2(a).Characteristics of growth?
Growth is a quantitative phenomenon
Most important property
= rate of growth e.g.
includes the  body weight
and  body composition and proportions
2015 Cattleman's Conference, SA Feedlot Association

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2(b). What is growth?
Growth  increase in hyperplasia + hypertrophy
Differentiation / Development   cell or tissue structure and functioning 
shape and dimensions of organs, systems, and hence phenotype of the organism
2015 Cattleman's Conference, SA Feedlot Association

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Chronological vs.
physiological age
Conception
Birth
Self-Accelerating
Inflection point
Self-retarding
Growth plateau
2015 Cattleman's Conference, SA Feedlot Association

11. 2(c).Growth and development
Growth and development in animals
directly dependant on influences in the external and internal environment
This implies that the growth genes need to draw on the external and internal environment for their expression
P = G + E + iGE
2015 Cattleman's Conference, SA Feedlot Association

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2(d).Growth process
Growth from birth to maturity
associated with continuous changes in body conformation and composition,
simulated by means of mathematical functions and allometric relationships
Mathematical description of growth
polynomial of suitable degree
2015 Cattleman's Conference, SA Feedlot Association

15. 2(e).Change in conformation / shape (Differentiation)
Selection for growth and efficiency

16. 2(f).Actual vs. potential growth
Actual growth
intrinsic characteristic of a given animal and represents the realisation of its genetic potential
result of various internal (genetic, sex, health etc.) and external (diet, housing etc.) influences
Potential growth
simulated in computerised simulation models
2015 Cattleman's Conference, SA Feedlot Association

17. 2(g).Shape of the growth curve
The shape of the postnatal growth curve is similar in all species and it is the result of a concomitant increase in bone, muscle and fat in that order.
Sigmoidal process
2015 Cattleman's Conference, SA Feedlot Association

18. 3. Efficiency of growth
Birth
Birth

19. 3(a).Parameters of Growth Efficiency
Growth rate or gain (ADG, kg or g); Feedlot gain(kg)
Dry matter intake (DMI)
Feed conversion ratio or Feed to growth ratio (FCR or F:G)
Kleiber ratio (kg0,75)
Residual feed intake (RFI)
All influenced by:
mature size (protein accretion rate)
rate of maturing
fatness
time scale
2015 Cattleman's Conference, SA Feedlot Association

20. 3(b).Growth hormone cascade (somatorophic axis)
1st order hormones
2nd order hormones
3rd order hormones

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4. Does Size matter?
2015 Cattleman's Conference, SA Feedlot Association

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4(a).Normal distribution of size (or any characteristics) in a population
2015 Cattleman's Conference, SA Feedlot Association

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4(b). Genetic variation?
Belgian blue
Bos taurus africanus
Bos taurus
2015 Cattleman's Conference, SA Feedlot Association

24. 5. From veld to efficient feedlot growth
How to optimize growth?
2015 Cattleman's Conference, SA Feedlot Association

25. 5(a). Feedlot performance depends on 3 factors:
Exploitation of compensatory growth (weaning phase to inflection point)
Build on skeletal system – muscular growth with optimum fattening
Exploitation of hypernutrition
Carcass dressing / dress-out%
2015 Cattleman's Conference, SA Feedlot Association

26. 5(b).Growth and Tissue composition
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27. 5(c).Nutrient priorities in the body
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Chronological vs.
physiological age
Slaughter
Fattening
Most Efficient growth
Feeding
Weaning
Conception
Birth
Self-Accelerating
Inflection point
Self-retarding
Growth plateau
2015 Cattleman's Conference, SA Feedlot Association

29. Changes in SA beef carcass composition (1972 – current)
Year
19721
19842
20103
20154
Age
Not available A AB C B
Bone %
13.7 -
17.7
17.9
20.4
17.3
18.4
18.3
21.0
Muscle
63.5
67.8
64.9
64.1
72.0
65.7
64.6
62.13
Fat
22.8
14.0
16.5
16.1
15.1
17.0
16.2
11.0
16.0
17.1
*Physical composition of the whole carcass was predicted from the chemical composition of the prime rib cut 1Naudé, 1972
2Klingbiel, 1984
3Schönfeldt, Naudé & Boshoff, 2010
4Hall, 2015

30. 5(d). Hypernutrition and selection for growth
Liver
Plasma
somatomedin
Tissue
Metabolism
N2 excretion
N2balance
Protein anabolism
Lipolysis
Hyperlipeamia
Hyperglycemia
Nutrition
Somatotrophin
Insulin
2015 Cattleman's Conference, SA Feedlot Association

31. 5(e).Carcass or Slaughter% (Dressing %)
260 kg; DR% 54-62%
230 kg; DR% ~ 54-58%
2015 Cattleman's Conference, SA Feedlot Association

32. High carcass yield (by means of genetics, age & nutrition)
2015 Cattleman's Conference, SA Feedlot Association

33. 5(f). Shifts in Animal Production and Animal Growth
Emancipation of human kind, hunter gatherers to domestication of livestock
Quantitative era – increasing numbers of animals
Quantitative era – numbers and maximum yield
Qualitative era – product quality
Consumer driven, origin, quality, safety, traceability,
sustainable and responsible systems
2015 Cattleman's Conference, SA Feedlot Association

34. 6. Old and New technologies to address the challenges?
2015 Cattleman's Conference, SA Feedlot Association

35. 6(a).Feed and Growth enhancing technologies
Major advances in feedstuffs and feeding in SA
Feed additives and antimicrobials
Efficient use of a variety of steroidal growth implants
Additive effects of beta-adrenergic agonists (manipulate efficiency and leanness) ↓
Shift the growth curve (manipulate tissue growth) – postpone fattening, and improve efficiency.
2015 Cattleman's Conference, SA Feedlot Association

36. 6(b).Selection for growth and efficiency
Selection of Cattle for  growth rate:
tenderness (due to age at slaughter)
carcass fat content,
flavour;
(DFD  environment + management)
ADG vs. SF rgenetic=-0,40 (age important)
More evident with compensatory growth
From Perry & Thompson (2005)
2015 Cattleman's Conference, SA Feedlot Association

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6(c).Use of ADG, FCR, RFI
Selection for ADG increases growth rates & DMI
FCR correlate with ADG (-0.70)
RFI correlates with DMI (0,45), FCR (0,31)
High RFI = less efficient
High RFI bulls have high DMI and FCR
Low RFI bulls consume >10% less feed, with >9% better FCR
Selection for better phenotypes – better performance
Positive correlation between RFI and carcass fatness
Variation exists in RFI within breed types & Kleiber ratio’s
2015 Cattleman's Conference, SA Feedlot Association

38. 6(d).Genomic technologies
Advances in molecular genetics
Identification of genes or genetic markers associated with production / quality traits
Candidate genes and genome scans to ID loci associated with traits (QTL mapping)
2015 Cattleman's Conference, SA Feedlot Association

39. Genomic technologies vs. growth and meat quality
Species
Candidate gene
Trait
Pig
Chicken
Cattle
Sheep
HAL,
MC4R,
RN, PRKAG3, AFABP/FABP4, HFABP/FABP3,
CAST
IGF2
EX-FABP, L-FABP
Leptin, Thyroglobulin, Myostatin
DGATI
Callipyge, GDF8
Meat quality /stress
Growth & fatness
Meat quality
IMF
Tenderness
Fatness
Fatness / marbling
Muscle growth
IMF / mabling
Muscular hypertrophy
2015 Cattleman's Conference, SA Feedlot Association

40. Consumer demand for lean meat
2015 Cattleman's Conference, SA Feedlot Association

41. Changes in fat content of red meat over time (summary from Dr Nicolette Hall)

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6(f).Ultrasound technologies and metabolic hormones to select for growth and efficiency
IGF-I, insulin, glc, leptin
useful but explain small proportion of variation
Ultrasound scanning
live animal measures are useful, but often not practical.
Explain variation but potential problems with meat quality traits
2015 Cattleman's Conference, SA Feedlot Association

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6(g).Consequence of physiological shift?
Changes in the phenotype and production characteristics of modern breeds of livestock – reproduction traits?
Sigmoidal growth curve and sequence of physiological events remained virtually unchanged
Rate and extent of these processes increased remarkably
University of Pretoria
2015 Cattleman's Conference, SA Feedlot Association

44. 6(h). Physiological limits vs. meat quality?
Wet carcass syndrome in mutton sheep breeds
Stress sensitivity and PSE syndromes in high-lean pigs
PSE in chickens
DFD in cattle
University of Pretoria
2015 Cattleman's Conference, SA Feedlot Association

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Artistic expressions of Auroch in caves at Lascaux and Altamira
Modern phenotypic version of “Auroch”
2015 Cattleman's Conference, SA Feedlot Association

46. 7. Options to consider for beef cattle feeding?
Feedlot cattle: days fattening period;
Longer fattening ~ 135 days?
ADG  1,5 -2 kg/day; FCE  5 – 8:1
Healthy feeding: more 1,8 kg/days
Feedlot profit:
Premium for feedlot cattle
decreased from 21% to 2%
What you make is what you save
Better management:
Backgrounding
Breed, gender & type of weaner
Adaptation to grower
Healthy feeding
Quality systems
Classification / Variation in type
Non-conformers (mid-weights)
University of Pretoria
2015 Cattleman's Conference, SA Feedlot Association

47. 2015 Cattleman's Conference, SA Feedlot Association
Thank you
2015 Cattleman's Conference, SA Feedlot Association