Presentation is loading. Please wait.

Presentation is loading. Please wait.

West Virginia University Extension Service Genetics in Beef Cattle Wayne R. Wagner.

Similar presentations


Presentation on theme: "West Virginia University Extension Service Genetics in Beef Cattle Wayne R. Wagner."— Presentation transcript:

1 West Virginia University Extension Service Genetics in Beef Cattle Wayne R. Wagner

2 West Virginia University Extension Service A Beef Animal’s Phenotype is completely determined by: 1)It’s genetic makeup  Cattle have 30 pairs of chromosomes  Genes located on chromosomes transmitted from parent to offspring  Genes code for production of proteins/enzymes

3 Quantitative – traits influenced by very few gene pairs. There is a distinct difference in phenotypes. Example horned vs polled or red vs black. West Virginia University Extension Service

4 25% Homozygous Black 50% Black w/Red gene 50% Black w/Red Gene 50% Red 25% Red BB black Bb black Bb black Bb red Bb black Bb black bb red bb red Let B = Black b = Red Bbbb B b B b Heterozygous X HeterozygousHeterozygous X Red

5 Qualitative – traits influenced by many pairs of genes. Show continuous variations or gradual variation from one extreme to the other. Expression of these traits is influenced by the environment. West Virginia University Extension Service

6 A Beef Animal’s Phenotype is completely determined by: 2)The Environment in which the animal is raised A.Unknown  Includes weather (temperature, humidity, precipitation)  Disease, internal & external parasites (vaccination program)  Feed/forage both quality and amount  Unique factors including injury/sickness B.Known  Age of dam  Age of calf  Sex of calf

7 The differences between two Hereford calves born in 2006 are due to differences in genetics and the environments in which they are raised. West Virginia University Extension Service

8 Beef producers keep records on various traits (Calving Ease, Weaning Weight, Yearling Weight, Scrotal circumference, IMF, REA) –These records are adjusted for known sources of variation so differences are due to genetics and unknown Environment → improves accuracy West Virginia University Extension Service

9 Additive Non-additive Known Unknown G P E

10 The objective of a seedstock producer is to limit differences due to Environmental effects as much as possible to get the best estimate of true genetic differences! West Virginia University Extension Service

11 Contemporaries – calves born in a similar time frame and then raised together and treated alike. West Virginia University Extension Service

12 Contemporary information is important because it is used in the computation of EPD’s. West Virginia University Extension Service

13 EPD’s – Expected Progeny Difference –Allows you to compare two bulls of the same breed but raised in different environments and under different health and nutritional programs. West Virginia University Extension Service

14 EPD’s reported in actual units. West Virginia University Extension Service

15 EPD’s are for within breed comparisons. West Virginia University Extension Service

16 EPD’s are not static – change as new and more data is collected. West Virginia University Extension Service

17 EPD is our best estimate of an animal’s genetic value for a particular trait at a specific time and given the information that is available at that time. –ie. In March 2006 you buy a yearling bull with a YW EPD of 70 lbs. In 2006 his dam raises another calf & yearling data is collected in March 2007 In 2006 his sire produces 3000 additional progeny with yearling data collected in 2007 The data added in 2007 updates the estimate of genetic value for the dam to a small degree and to the estimate of genetic value of the sire to a somewhat larger degree. West Virginia University Extension Service

18 EPD’s depend upon accurate contemporary information being reported. West Virginia University Extension Service

19 EPD’s are estimates of how future progeny will perform when mated at random to the average of the breed. West Virginia University Extension Service

20 Breed average EPD’s ≠ 0 West Virginia University Extension Service

21 Acc is a measure of risk associated with an EPD. Acc is an indication of how much an EPD might change as additional data is collected. West Virginia University Extension Service

22 Acc ranges from 0 – 1 –Acc below.4 would be low –Acc between.4 and.8 are moderate –Acc above.8 are high West Virginia University Extension Service

23 Acc is an indication of how much an EPD might change. (Possible Change) West Virginia University Extension Service

24 Possible Change Values for Different Traits - Angus AccCEDYWMilkIMFREA

25 If you produce your own replacement females, the last 3 bulls used in a calf’s pedigree accounts for 87 ½ of the genetic makeup and potential. West Virginia University Extension Service

26 The value of a herd depends upon the bulls used. West Virginia University Extension Service

27 Often times, when cattle are raised in an excellent environment, it is difficult to determine how much of an animals superiority is due to nutrition, vaccination programs, etc and how much is genetic. West Virginia University Extension Service

28 Breed Average EPD’s (Non-Parent) Breed Trait BWYWMilkGLScrotal Circum IMFREA Angus Charolais Hereford Gelbvieh Limousin Maine Anjou Red Angus Simmental

29 Crossbreeding –Heterosis – advantage of crossbred animal compared to average of parental breeds. –Complementarity – combination of breed strengths. West Virginia University Extension Service

30 Heterosis: –Traits with low levels of heritability usually show significant amounts of heterosis. –Improves an animal’s ability to withstand stress. West Virginia University Extension Service

31 Economically Important Traits 1)Reproduction/Fertility a)Calving Ease b)Gestation Length c)Scrotal Circumference d)Cycling before breeding season starts 2)Feed Efficiency a)Difficult to measure b)Indicators – ADG & YW (should be within a frame size) 3)Product Merit a)REA b)Marbling West Virginia University Extension Service

32 Future –Feed Efficiency – RFI –Fleshing Ability –Marker Assisted Selection –Balance/Optimums West Virginia University Extension Service

33 Why RFI? –Feed:gain determines variable costs and is influenced by environment, body condition, appetite, stage of growth and rate and composition of gain. West Virginia University Extension Service

34 Genetic makeup is the foundation of a cow herd. West Virginia University Extension Service

35 West Virginia University Extension Service


Download ppt "West Virginia University Extension Service Genetics in Beef Cattle Wayne R. Wagner."

Similar presentations


Ads by Google