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F.W.C. Neser. Country% Off-take South Africa (Commercial)32 South Africa (Emerging)21 South Africa (Communal)6 Australia28 New Zealand37 European Union34.

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Presentation on theme: "F.W.C. Neser. Country% Off-take South Africa (Commercial)32 South Africa (Emerging)21 South Africa (Communal)6 Australia28 New Zealand37 European Union34."— Presentation transcript:

1 F.W.C. Neser

2 Country% Off-take South Africa (Commercial)32 South Africa (Emerging)21 South Africa (Communal)6 Australia28 New Zealand37 European Union34 USA38 Argentina, Uruguay30 Brazil22 Source -National beef Cattle Sector Strategy and Implementation Framework – February 2006

3 CommunalCommercialStud Calving %40%65%85% Pre-wean mortality50%4%2% Post-wean mortality15%2% Calves wean/annum/25 cows51621 Calves available for sale21520 Average weight150kg180kg205kg Price/kgR9.00R20.60R21.25 Potential monetary valueR2700R55620R86100 Potential monthly incomeR225R4635R7175

4 Fitness = NATURAL SELECTION: Survival Fertility

5 The heritability of fitness traits are usually low and will be severly influence by inbreeding depression and heterosis (Bourdon, 1997)

6 Unlike the dairy farmer, the beef farmer derives his entire income from calves born into the herd, making fertility unquestionably the most important trait. Results of a study placed the economic importance of fertility, growth rate and carcass quality in the ratio 10:2:1. This means that fertility is 5x more important than growth and 10x more than carcass quality (Dr G Coulter-Kanada)

7 Farm size1000ha Stocking rate6ha/LSU Weaner priceR Carcass priceR Price of C gradesR 23.00

8 All animals are equally fertile It is impossible to improve fertility by selection Feed your animals fertile

9 Phenotype Genotype Environment Model P = μ + G + E

10 Nutrition & management that affect the animals in the herd now! Cows: manage heifers to attain mating weights (65% of adult weight) manage 1 st calf cows (e.g. early weaning & mate separately) restrict joining & cull empties control reproductive diseases cull females having difficult births

11 Bulls: breeding soundness test (adequate scrotal size) good physical structure (and sheath) adequate pre-breeding nutrition (body condition) control reproductive diseases multi-sire groups, mating ratios, serving capacity

12

13 Female fertility is a complex trait with many components. Each component use resources. Nature select for intermediate optimum. Holistic approach. To much selection emphasis on production could decrease reproduction

14 Did not calf Less fertile Above average fertile

15 Age at first calving(Optimum) ICP: First and second calf (Min) Average lifetime ICP(Min) Days to calving whole herd recording (female inventory) bull in date and service sire(s) subsequent calving date record culls, especially non-calvers /culled empty

16 Scrotal circumference measure scrotal circumference all young bull at around 400d - Scrotal circumference also contributes to DC EBV - Early indicator of DC EBV for young bulls Mating ability Fertility Performance of ancesters and daughters

17 Age at puberty Age at first calving Days to calving Calving interval Calving ease Days open Gestation length0.15 Longevity Stayability Scortal circumference

18 TraitProduction levelh 2 Brahman Conception rate Pregnancy rate Calving rate Weaning rate Days to calving0.22 Tropical Composite Conception rate Pregnancy rate Calving rate Weaning rate Days to calving0.13

19 TraitLifetime annual calving rate Lifetime annual weaning rate Mating1 Conception rate Pregnancy rate Calving rate Days to calving Weaning rate Mating 2 Conception rate Pregnancy rate Calving rate Days to calving-1.0*-0.96 Weaning rate Days to cycling Lactation anoestrous interval Lactation cyclicity

20 Correlations show selection for reduced age at puberty will result in increased reproductive performance at both the early and lifetime stages.

21 Male: Sperm quality Hormonal levels

22 LH – Luteinising hormone Testosterone production Influences onset of puberty Inhibin Regulation of sperm production IGF-I – Insulin-Like Growth Factor-I Growth stimulus Bull SC and sperm motility and heifer puberty

23 BrahmanTropical Composite CategoryTraith2h2 h2h2 Inhibin HormoneLuteinising Horm Insulin-like GF Mass Activity Semen QualityMotility months% Normal Burns and Corbet 2012

24 Bull trait Age (Mths) Pregnancy Rate Calving Rate Days to calving Hormones Inhibin Luteinising Hormone IGF-I Semen Quality Mass Activity Motility %normal sperm Scrotal and sheath Scrotal circumference Sheath score

25 Bull trait Age (Mths) L. Anoestrous interval Calving Rate Day to calving Hormones Inhibin Luteinising Hormone IGF-I Semen Quality Mass Activity Motility %normal sperm Scrotal and sheath Scrotal circumference Sheath score

26 No genetic antagonisms between semen quality and production traits Scrotal and semen traits are genetically related to female age of puberty Scrotal traits but especially semen traits related to reproductive output in cows

27 Recognition of novel phenotypes associated with economically important traits Recognition of novel phenotypes associated with economically important traits Determination if phenotype can be measured accurately Determination if phenotype can be measured accurately Assessment of variation associated with phenotype Assessment of variation associated with phenotype Proportion of variation attributable to genetics Proportion of variation attributable to genetics Programs to implement change Programs to implement change

28 Birth Year Number Exposed Number Pregnant % Pregnant

29 Heifers should conceive first time and calf not later than 33 months Each cow should calf each year (Herefords currently 384 days) 95% Strive to use Days to Calving – Mating seasons compulsory DNA technology – Fertility markers

30 Traitsh2h2 rIncrease in accuracy Progeny equivalents Age at first calving Heifer preg. Rate Scrotal Circumference (12mth) Stayability Accumulated production

31 Thanks


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