Verse moet weer kan herbeset raak as hulle op 2 jaar gekalf het

Transcription

1 31

2 Verse moet weer kan herbeset raak as hulle op 2 jaar gekalf het Netto voerinname In enige veevertakking maak voer meer as die helfte van die kostes van die dier uit. Daar is egter bewys dat sekere diere tot 25% minder kan vreet as ander en dieselfde groei kry. Daar is nie n korrelasie tussen netto voerinname en groei nie. Neem gerus deel aan skemas waarvan voerinname bepaal word om te kyk of die minder vreet geen in die kudde teenwoordig is. Daar is klaar genetiese merkers op die mark beskikbaar wat netto voerinname bepaal, en dit is net n kwessie van tyd of ons dit met groot akkuraatheid gaan aanwend. Teel vir diere wat funksioneel doeltreffend is Die Indicus faktor in die Beefmasterras maak hom baie aanpasbaar in Suider Afrika omstandighede en speel n groot rol in faktore soos siekteweerstand, bosluisbeheer, gladdehaar, loopvermoë ens. Die Indicus diere se leeftyd is ook langer. Koeie het minder onderhoud nodig as verse en kan wins verhoog. Die Beefmaster is ook saamgestel uit Britse rasse wat vrugbaarheid en vroegrypheid inbring en ook Europese rasse wat groei en bespiering inbring. Dit is wat die Beefmaster uniek maak teenoor baie saamgestelde rasse. Die Lasater filosofie is gebaseer op funksionaliteit. Huidiglik is die Beefmaster een van die mees funksionele rasse in Suid-Afrika as on na speenkalfgewigte en reproduksie eienskappe kyk. Kommersiële boere kan baat vind met die koop van Beefmasterbulle. Probeer eerder vroeër as later om teleurstelling met produksie te vermy. 32 B E E F M A S T E R

3 B E E F M A S T E R

4 red meat The role of IN THE S.A. ECONOMY Frikkie Maré The total land size of South Africa consists of approximately 1.2 million square kilometres. Of the total land size 81.8 % are use for agricultural purposes of which only 11.9 % are accounted for as arable land on which crops can be produced. The rest of the available agricultural land can only be utilized by livestock production due to mainly climate related factors that limits the production of crops. It is due to the livestock sector that people are living in and utilising the most extensive regions of the country, making livestock, after poultry, the second largest agricultural industry in South Africa. To sketch and understand the size of the red meat industry and the role it plays in the South African economy it is necessary to look at the figures as presented by the Department of Agriculture, Forestry and Fisheries (2011). The total gross value of South African agriculture production, for the 2010/2011 season, was estimated on R million while its contribution to the GDP was approximately R60 billion or 2.5%. Although the contribution of primary agriculture to the country s GDP may seem small, the indirect role of agriculture in the economy must be remembered. The backward (purchase of fertilisers, medicine, implements) and forward (supply raw materials to the manufacturing industry) linkages of agriculture plays and enormous role in the other industries as approximately 70% of the primary agricultural output are used as intermediate products in other industries. Animal products, horticultural products and field crops contributed respectively 49.5%, 25.5% and 25.1% to the gross value of agricultural production. The contribution of each of the agricultural sectors respectively to the gross income of producers was R million for animal products, R million for horticultural products and R million for field crops. Animal and horticultural products show increases in gross income of 4.7% and 0.7% respectively from the previous year (2009/2010), while field crops has decreased with 12%. Figure 1 illustrates the differences in gross farm income between the different sectors. It is clear that the animal production section had shown the best continuous growth over the last five years, while horticulture also shown growth but the income from field crops had decreased. Figure 1: Gross farm sector income (July-June) Source: Economic review of the South African Agriculture 2010/2011, DAFF Figure 2 gives a summary of the gross income from the major agricultural products. Poultry meat is currently the largest income receiver on R million, while red meat is in the second place. Maize that was in the third place until 2008/2009 shown an enormous decrease in gross income and is currently in fifth place (R million) after fruit (R million) and vegetables (R million). The low income from maize for the 2010/2011 can be ascribe to low producer prices and will increase again as the price of maize increase. Figure 2: Gross income from major products (July to June) Source: Economic review of the South African Agriculture 2010/2011, DAFF Another important factor in determining the role of red meat in the economy is the consumption expenditure on food. This indicates how much money private individuals spend on different food types. Figure 3 illustrates the expenditure on the five largest food groups. The expenditure for 2010/2011 on meat increase with 6.5%, on fruit and vegetables with 7%, on oils and fats with 9.6% and on milk, milk products and eggs with 4%. The expenditure on bread grains decrease with 4% during the same period. Meat represents the largest proportion of expenditure with 34% of the total. 34 B E E F M A S T E R

5 B E E F M A S T E R

6 Figure 3: Private consumption expenditure on major food items (July-June) Source: Economic review of the South African Agriculture 2010/2011, DAFF When the all the figures of gross value of agriculture, gross income of agriculture and private expenditure on agricultural products is taken into account it is clear that meat plays the largest role in the economy of all the agricultural products. Although the gross income of poultry meat is higher than that of red meat, red meat still is in the second highest place. The outlook for red meat remains positive as BFAP (2011) predicts that both production and consumption of will growth steadily over the next eight years with about 28%. The demand will stay somewhat higher than the supply during this period resulting in a shortage that will be make up by imports. The demand for sheep meat will also increase over the outlook period. The increase in demand is however more than that of supply and the net volume of sheep meat that is imported will increase over the outlook period. The increase in the demand for red meat will ensure that the price for this commodity remain strong in future. The red meat industry will thus stay a competitive force in the economy of the South African agricultural sector. 36

7 B E E F M A S T E R

8 38 B E E F M A S T E R

9 B E E F M A S T E R

10 40 B E E F M A S T E R

11 Breeding Values- HOW TO UNDERSTAND AND USE IT Teelwaardes HOE OM DIT TE VERSTAAN EN GEBRUIK Leslie Bergh LNR-Diereproduksie-instituut, Privaatsak X2, Irene, 0062 Suid-Afrika, Tel. +27 (0) , Sel +27 (0) , E-pos: Introduction Estimated Breeding values or EVBs just like ordinary performance test indexes is a valuable tool in selection and breeding of beef cattle. However, it is not the alpha and omega of breeding and should off course be used purposefully and in a balanced manner, in combination with other tools such as functional evaluation. It is of no use to breed a bull that can grow at 2.5kg per day, but he can not walk! It is also very important that you make sure that your priorities are correct when it comes to selection. Reproduction or fertility should always be number one and you should never compromise on this trait. If too much emphasis is placed on other traits at the expense of fertility traits, you are for sure looking for trouble - the kind that will cost you lots of money - no matter what tools you are using in your selection and breeding plans. It is equally important that you know exactly what your breeding objective is in the breeding of your cattle. [You know the story that if you do not know where you go, chances are 100% that you will get there]. As with other tools (such as performance test indexes), EBVs can also be used incorrectly. But you must be careful that you do not throw away the baby with the bath water it s not the tool s (EBV s) fault if you (or your adviser / consultant) use the tool Inleiding Teelwaardes is net soos gewone prestasietoets indekse n uiters waardevolle hulpmiddel in seleksie en teling van vleisbeeste. Dit is egter nie die alfa en omega van teling nie en moet natuurlik doelgerig en op n gebalanseerde wyse gebruik word in kombinasie met ander hulpmiddels soos funksionele evaluasie. Dit help tog nie om n bul te teel wat teen 2.5kg per dag kan groei, maar hy kan nie loop nie! Verder is dit ook baie belangrik dat jy sal seker maak dat jou prioriteite reg is wanneer dit kom by seleksie. Reproduksie of vrugbaarheid moet altyd nommer een wees en daar behoort nooit kompromieë aangegaan te word ten opsigte van hierdie eienskap nie. Indien te veel klem op ander eienskappe geplaas word ten koste van vrugbaarheidseienskappe, soek jy vir seker moeilikheid die soort wat jou baie geld gaan kos ongeag watter hulpmiddels jy gebruik in jou seleksie en teelplanne. Dit is net so belangrik dat jy presies weet waarna toe jy wil gaan met die teling van jou beeste, dit wil sê wat jou teeldoelwitte is. [Jy ken mos die storie dat as jy nie weet waarheen jy gaan nie, is jou kanse 100% om daar te kom]. Net soos met ander hulpmiddels (soos prestasietoets indekse), kan teelwaardes ook verkeerd gebruik word. Maar dan moet jy oppas dat jy nie die baba met die badwater weggooi nie dit is mos nie die hulpmiddel (teelwaardes) se B E E F M A S T E R

12 incorrectly. You should thus make sure that you are well informed about the interpretation of EBVs and also listen to the right people when you need help using breeding values for selection and breeding. What is BLUP? BLUP (Best Linear Unbiased Prediction) is merely a sophisticated mathematical method used to obtain estimated breeding values (EBVs), using performance test data and pedigrees. What is an EBV? - An animal s breeding value is a prediction of its genetic ability, in other words how future progeny of this animal should perform for this trait within the specific breed. - The following performance and pedigree data is used in the calculation of breeding values: The performance of an animal relative to its contemporaries (animals that were exposed to the same environmental conditions with regard to herd, farm, feeding, season, management, etc.). Similarly, the performance of all the animal s family (parents, siblings, offspring, etc.) in the contemporary groups in which they were tested, taking into consideration the heritability of the trait. The performance of the animal in respect of other measured traits, taking into consideration the genetic correlations between the traits. The genetic links or connections between herds, years, seasons, groups, etc. - From the above it is clear that a breeding value is a more accurate indication of an animal s genetic ability than the animal s performance index for the trait, because all available information is used to obtain an EBV, not only the animal s own performance. - Breeding Values are not static, i.e. an animal s breeding values can change with each new BLUP analysis as more and more data from the animal, his relatives and progeny becomes available. For this reason the latest available EBVs should always be used. It is also important to remember that the greatest changes in an animal s EBVs happens when his/her own measurement/performance for a particular trait is included in a BLUP analysis (as opposed to a calf that has not been performance tested skuld nie as jy (of jou adviseur/konsultant) die hulpmiddel verkeerd gebruik nie? Maak dus seker jy is goed ingelig oor die interpretasie van teelwaardes en luister ook na die regte mense as jy hulp soek met die gebruik van teelwaardes by seleksie en teling. Wat is BLUP? BLUP (Best Linear Unbiased Prediction) is bloot die gesofistikeerde wiskundige metode wat gebruik word om beraamde teelwaardes of kortweg teelwaardes te verkry met behulp van prestasietoetsdata en stambome. Wat is n Teelwaarde? - n Dier se teelwaarde is n voorspelling van sy genetiese vermoë, met ander woorde hoe toekomstige nageslag van hierdie dier behoort te presteer vir hierdie eienskap binne die spesifieke ras. - Die volgende prestasie- en stamboomdata word gebruik in die berekening van teelwaardes: Die prestasie van n dier relatief tot sy tydgenote (diere wat blootgestel was aan presies dieselfde omgewingstoestande wat betref kudde, plaas, voeding, seisoen, bestuur, ensovoorts. Soortgelyk, die prestasie van al die dier se familie (ouers, broers en susters, nageslag, ensovoorts) in hul onderskeie kontemporêre groepe waarin hulle getoets was, met inagneming van die oorerflikheid van die betrokke eienskap. Die prestasie van die dier ten opsigte van ander gemete eienskappe, met inagneming van die genetiese korrelasies tussen die eienskappe. Die genetiese skakels of koppelings tussen kuddes, jare, seisoene, groepe, ensovoorts. - Uit bogenoemde is dit duidelik dat n teelwaarde n meer akkurate aanduiding van n dier se genetiese potensiaal is as die dier se prestasie indeks vir die betrokke eienskap, omdat alle beskikbare inligting gebruik word om n teelwaarde te beraam, nie net die dier se eie prestasie nie. - Teelwaardes is nie staties nie, met ander woorde n dier se teelwaardes kan verander met elke nuwe BLUP ontleding, soos wat meer en meer data van die dier, sy verwantes en later ook nageslag beskikbaar word. Vir hierdie rede moet die nuutste beskikbare teelwaardes altyd gebruik word. Dit is ook nodig om te onthou dat die grootste veranderings in n dier se teelwaardes gebeur wanneer sy/haar sy eie meting/prestasie vir n 42 B E E F M A S T E R

13 B E E F M A S T E R

14 44 B E E F M A S T E R

15 B E E F M A S T E R

16 yet) and then again when the animal s first offspring s measurements for a particular trait are included in the BLUP analysis. The biggest change in a bull s weaning weight maternal EBV occurs when his daughters first calves weaning weights are included in the BLUP analysis. - The accuracy value (which varies between 0 and 99%) of a breeding value is an indication of the amount of performance test data (from the animal and its relatives) which was taken into account in the relevant BLUP analysis for that trait. The more information available, the higher the accuracy. If the accuracy is relatively low, it is usually because the animal was not tested for that trait. In such cases the chance is large that the animal s breeding value will change in the future when more performance test data becomes available. A high accuracy means that the chance is small that the animal s breeding value will change with the addition of data. The breeding values of an AI bull with many offspring will, for example, have a very high accuracy. - Breeding values are typically expressed in the unit of measurement, e.g. kg for weight EBVs. - To interpret an EBV, it should always be compared with the average breeding value of the breed and the particular herd. For example, an EBV of +5 kg for weaning weight should first be compared with the particular breed and herd averages to find out whether it is good or bad. To make this comparison easier, we now also calculate breeding value indexes which express the animal s breeding value as a percentage of the breed s average, where the breed average, is equal to The BLUP method makes it possible to separate the influence of the environment (farm, year, season, group, etc.) on a particular trait from the genetic influence. This separation makes it possible to compare the genetic merit (or breeding value) of animals over years, herds, seasons, groups, etc., provided that sufficient genetic links are available. (By the way, the lack of genetic links across breeds is why EBVs are not directly comparable across breeds). The use of AI bulls, the purchase of bulls from other breeders who do performance testing and the exchange of bulls between breeders, is the best way to obtain strong genetic links between herds. - Breeding values are expressed as a deviation from the base year. This means that, to ensure that breeding values are compared year after year against the same basis, a certain year is arbitrarily chosen in which the average breeding values for animals born in that year are equated to zero. For example, if the base year is 1990, an EBV of +6 kg for weaning weight direct means the animal s breeding value is 6 kg more than the average EBV of all animals in the breed born in Breeding values can be calculated for animals that are not tested for that particular trait, for example for young animals not yet performance tested, and for traits that can only be measured in one of the genders, for example, maternal ability or milk production. In such cases, the animal s breeding value is calculated based on the animal s performance in other traits that are genetically correlated, as well as the performance of the animal s family. As already said, a bull s maternal weaning weight EBV is only really accurate when his daughters calves weaning weights are included in the BLUP analysis. betrokke eienskap ingesluit word in n BLUP ontleding (teenoor n kalfie wat nog nie prestasiegetoets was nie), en dan weer wanneer die dier se eerste nageslag se metings vir n betrokke eienskap ingesluit word in die BLUP ontleding. Die grootste verandering in n n bul se speengewig maternale teelwaarde vind plaas wanneer sy dogters se eerste kalwers se speengewigte ingesluit word in die BLUP ontleding. - Die akkuraatheid syfer (wat wissel tussen 0 en 99%) van n teelwaarde is n aanduiding van die hoeveelheid prestasietoetsdata (van die dier self en sy verwantes) wat in berekening gebring is in die betrokke BLUP ontleding vir daardie eienskap. Hoe meer inligting beskikbaar is, hoe hoër is die akkuraatheid. As die akkuraatheid relatief laag is, is dit gewoonlik omdat die dier self nie getoets was vir daardie eienskap nie. In sulke gevalle is die kans groot dat die dier se teelwaarde kan verander in die toekoms wanneer meer prestasietoetsdata beskikbaar raak. n Hoë akkuraatheid beteken dat die kans klein is dat die dier se teelwaarde sal verander met die byvoeging van data. n KI bul met baie nageslag se teelwaardes sal byvoorbeeld n baie hoë akkuraatheid hê. - Teelwaardes word meestal uitgedruk in die eenheid van meting, byvoorbeeld kg vir gewig teelwaardes. - Om n teelwaarde te interpreteer, moet dit altyd vergelyk word met die gemiddelde teelwaarde van die betrokke ras en die betrokke kudde. n Teelwaarde van byvoorbeeld +5kg vir speengewig direk moet dus eers met die betrokke ras- en die kudde gemiddeldes vergelyk word om te weet of dit goed of sleg is. Om hierdie vergelyking te vergemaklik, word daar deesdae ook teelwaarde indekse bereken wat die dier se teelwaarde uitdruk as n persentasie van die ras se gemiddeld, waar die ras gemiddeld gelyk gestel word aan Die BLUP-metodiek maak dit moontlik om die invloed van die omgewing (plaas, jaar, seisoen, groep, ensovoorts) op n betrokke eienskap te kan skei van die genetiese invloed. Hierdie skeiding maak dit dan moontlik om die genetiese meriete (of teelwaarde) van diere te kan vergelyk oor die jare, kuddes, seisoene, groepe, ensovoorts, op voorwaarde dat daar voldoende genetiese koppelings beskikbaar is. (Terloops, die gebrek aan genetiese koppelings oor rasse is die rede waarom teelwaardes nie direk vergelykbaar is oor rasse nie). Die gebruik van KI bulle, die koop van bulle by ander telers wat prestasietoetsing doen en die uitruil van bulle tussen telers, is die beste maniere om sterk genetiese koppelings tussen kuddes te verkry. - Teelwaardes word uitgedruk as n afwyking van die basisjaar. Dit beteken dat, om te verseker dat teelwaardes jaar na jaar teen dieselfde basis vergelyk word, daar arbitrêr n sekere jaar gekies word waarin die gemiddelde teelwaardes vir diere gebore in daardie jaar in die betrokke ras gelyk gestel word aan nul. Indien die basisjaar byvoorbeeld 1990 is, beteken n teelwaarde van +6kg vir speengewig direk dat die dier se teelwaarde 6kg hoër is as die gemiddelde teelwaarde van alle diere in die ras gebore in Teelwaardes kan bereken word vir diere wat nie getoets is vir daardie spesifieke eienskap nie, byvoorbeeld vir jong diere wat nog nie prestasie getoets is nie, asook vir eienskappe wat slegs in een van die geslagte gemeet kan word, byvoorbeeld moederlike vermoë of melkproduksie. In sulke gevalle word die dier se teelwaarde bereken op grond van die dier se prestasie 46 BBE EEF FM A SST TE ER R

17 B E E F M A S T E R

18 48 B E E F M A S T E R

19 - The BLUP method makes it possible to distinguish direct effects from maternal effects on traits where the mother has a direct impact on the performance of her calf, such as birth weight and weaning weight. For example, weaning weight direct EBV is an indication of the calf s own pre-weaning growth ability, while the maternal breeding value is an indication of the mother s maternal ability, especially milk production. Myths About Breeding Values Perhaps we should also stamp out a few myths regarding performance testing and breeding values, namely: - The fact that you measure (performance test) a certain trait in your herd, does not necessarily mean that you have to select animals with the highest (or lowest) breeding values for that trait. The preferred animal depends inter alia on your breeding goals, available feed, climate, breeding system and production system. Consider shoulder height: If your goal is to breed medium frame animals, you will not select bulls with high breeding values for shoulder height only because they were measured for shoulder height in a Phase C or D test, will you? The mere measurement of a trait therefore has nothing to do with how the particular breeding value is used. - Performance testing and breeding values as such do not make cattle less efficient. An animal s genetic makeup is not changed by simply weighing an animal and calculating a breeding value for it. It is only when selection (by the breeder or inspector) in a specific direction occurs that the genetic composition of a breed or herd is changed. - Although there are positive genetic correlations between birth weight, weaning weight, growth rate (ADG) and mature weight, these correlations are not 100%. This means that it is possible to genetically increase growth rate without necessarily increasing birth weight and/or mature weight. Description of Traits and Guidelines for Selection With each of the traits a guideline for selection is given. Please note that these are general guidelines and can vary from breeder to breeder, depending on your specific breeding objectives and needs. REPRODUCTION - Calving Rate This EBV is an indicator of fertility and the retention of a bull s female offspring. For a bull to get a high calving rate EBV, his daughters firstly need to be retained in the breed (i.e. a large percentage of his daughters born, are retained as replacement heifers, or are sold to co-breeders) and secondly, his daughters need to calve regularly until the age of 6 years. A hundred daughters of an average bull will, for example, give together 97 calves before the age of 6 years. The breeding value therefore reflects the number of calves that 100 of a bull s daughters will give more or less than the average bull. All relatives measurements are fully in ander eienskappe wat geneties gekorreleer is en ook op die prestasie van die dier se familie. Soos reeds gesê, word n bul se speengewig maternale teelwaarde eers werklik akkuraat wanneer sy dogters se kalwers se speengewigte ingesluit word in die BLUP ontleding. - Die BLUP metodiek maak dit moontlik om direkte effekte te skei van die moeder effekte vir eienskappe waar die moeder n direkte invloed het op die prestasie van haar kalf, vir eienskappe soos geboortegewig en speengewig. Die speengewig direk teelwaarde is byvoorbeeld n aanduiding van die kalf se eie voorspeense groeivermoë, terwyl die maternale teelwaarde n aanduiding is van die moeder se moederseienskappe, veral melkproduksie. Mites oor Teelwaardes Miskien moet ons nou ook sommer n paar mites met betrekking tot prestasietoetsing en teelwaardes die nek in slaan, naamlik: Die feit dat jy n sekere eienskap meet (prestasietoets) in jou kudde beteken nie noodwendig dat jy diere met die hoogste (of laagste) teelwaardes vir daardie eienskap moet selekteer nie. Die gewensde dier hang onder meer af van jou teeldoelwitte, beskikbare voeding, klimaat, teelstelsel en produksiestelsel. Neem byvoorbeeld skouerhoogte: As jou teeldoelwit is om mediumraam diere te teel gaan jy mos nie bulle met baie hoë skouerhoogte teelwaardes selekteer net omdat hulle in Fase C of D gemeet is vir skouerhoogte nie. Die blote meting van n eienskap het dus niks te doen met hoe jy die betrokke teelwaarde gebruik nie. Prestasietoetsing en teelwaardes as sulks maak nie beeste groter en minder doeltreffend nie. n Dier se genetiese samestelling verander nie deur dit te weeg en n teelwaarde vir die dier te bereken nie. Dit is eers as seleksie (deur die teler of keurder) in n spesifieke rigting plaasvind dat die genetiese samestelling van n ras of kudde verander word. Alhoewel daar positiewe genetiese korrelasies bestaan tussen geboortegewig, speengewig, groeitempo (GDT) en volwasse gewig, is hierdie korrelasies nie 100% nie. Dit beteken dat dit moontlik is om groeitempo geneties te verhoog sonder om noodwendig geboortegewig en/of volwasse gewig te verhoog. Beskrywing van Eienskappe en Riglyne vir Seleksie By elk van die eienskappe word n riglyn gegee vir seleksie. Let egter op dat hierdie algemene riglyne is en dat dit kan verskil van teler tot teler, afhangende van jou spesifieke teeldoelwitte en behoeftes. REPRODUKSIE - Kalftempo Dié teelwaarde is n aanduiding van die vrugbaarheid asook die retensie van n bul se vroulike nageslag. Vir n bul om n hoë kalftempo teelwaarde te kry, moet sy dogters eerstens behoue bly in die ras (met ander woorde n groot persentasie dogters wat gebore word, word behou as vervangingsverse, of word aan mede-telers verkoop) en tweedens moet sy dogters gereeld kalf tot op die ouderdom van 6 jaar. Honderd dogters van n gemiddelde bul sal tesame byvoorbeeld B E E F M A S T E R

20 taken into account via the pedigrees. The EBV is only published for males in the breed. Select bulls with above average calving rate breeding values for fertile daughters with high retention of their progeny. - Scrotal circumference This EBV is an indication of the animal s genetic ability for scrotal size as measured in Phase C and D growth tests. Avoid bulls with low breeding values for scrotum circumference for fertile bulls that can cover a lot of cows. BIRTH - Birth Weight Direct This EBV is an indication of the animal s genetic ability for birth weight. Animals with lower breeding values will breed progeny with lighter birth weights and consequently a smaller chance of calving problems in the mothers. - Birth Weight Maternal This EBV is an indicator of a cow s genetic ability to limit the growth of a calf until birth (as a natural protection from calving problems). The maternal EBV of a bull is an indication of his daughters ability to limit the birth weight of their offspring. GROWTH RATE - Weaning Weight Direct This EBV is an indication of the animal s own genetic ability to grow until weaning age. Select bulls with above average weaning weight direct EBVs for calves that will grow rapidly and thus have high weaning weights. - Weaning Weight Maternal This EBV is an indicator of a cow s (the calf s mother) genetic maternal ability (primarily milk production) to create an environment in which her calves can grow optimally. The weaning weight maternal EBV of a bull is an indication of his daughter s maternal ability to wean heavy calves. Please note that there is usually a low negative genetic correlation between weaning weight direct and maternal breeding values. When you are selecting for weaning weight, both these breeding values thus need to be taken into account. Select bulls with above average weaning weight maternal breeding values to breed daughters with good maternal ability that could wean heavy calves. - Yearling Weight This EBV is an indication of the animal s genetic ability to grow until one year of age. Please note that yearling weight is a function of pre-wean and post weaning growth. Select bulls with average to slightly above average yearling weight EBVs for average sized animals. - Weight: 18-Months This EBV is an indication of the animal s genetic ability to grow until 18 months of age. It is also to some extent an indication of the animal s mature weight. Like yearling weight, 18 months weight is a function of pre-and post weaning growth. Select bulls with average to slightly above average 18-month weight EBV for average sized animals. - Mature Weight This EBV is an indication of the animal s genetic ability for mature weight. Weights of cows 4 years and older at weaning of their calves to be used to estimate adult weight EBV. Select average adult breeding values for average sized animals. - Average daily gain (ADG) This EBV is an indication of the animal s genetic ability for post weaning growth, as measured in Phase C and D growth tests. 97 kalwers voor die ouderdom van 6 jaar gee. Die teelwaarde weerspieël dus die aantal kalwers wat 100 van n bul se dogters meer of minder as die gemiddelde bul sal gee. Alle verwantes se metings word ten volle deur die stambome in ag geneem. Die teelwaarde word net vir die manlike diere in die ras gepubliseer. Selekteer bulle met bogemiddelde kalftempo teelwaardes vir vrugbare dogters met hoë retensie van nageslag. - Skrotumomvang Dié teelwaarde is n aanduiding van die dier se genetiese vermoë vir skrotumomvang soos gemeet in Fase C en D groeitoetse. Vermy bulle met lae skrotumomtrek teelwaardes vir vrugbare bulle wat baie koeie kan dek. GEBOORTE - Geboortegewig Direk Dié teelwaarde is n aanduiding van die dier se genetiese vermoë vir geboortegewig. Diere met laer teelwaardes sal nageslag gee met ligter geboortegewigte met n gevolglike kleiner kans vir kalwingsprobleme by die moeders. - Geboortegewig Maternaal Dié teelwaarde is n aanduiding van n koei se genetiese vermoë om n kalf (fetus) se groei tot geboorte te beperk (soos n natuurlike beskerming teen kalwingsprobleme). Die maternale teelwaarde van n bul is n aanduiding van sy dogters se vermoë om die geboortegewig van hul nageslag te beperk. GROEITEMPO - Speengewig Direk Dié teelwaarde is n aanduiding van die dier se eie genetiese vermoë om te groei tot op speenouderdom. Selekteer bulle met bogemiddelde speengewig direkte teelwaardes vir kalwers wat vinnig groei en dus hoë speengewigte het. - Speengewig Maternaal Dié teelwaarde is n aanduiding van n koei (die kalf se moeder) se genetiese moederlike vermoë (hoofsaaklik melkproduksie) om n omgewing te skep waarin haar kalwers optimaal kan groei. Die speengewig maternale teelwaarde van n bul is n aanduiding van sy dogters se moederlike vermoë om swaar kalwers te speen. Let asseblief op dat daar gewoonlik n lae negatiewe genetiese korrelasie is tussen speengewig direkte- en maternale teelwaardes. Wanneer daar dus vir speengewig geselekteer word, moet telers albei hierdie teelwaardes in ag neem. Selekteer bulle met bogemiddelde speengewig maternale teelwaardes om dogters te teel met goeie moederseienskappe wat swaar kalwers kan speen. - Jaaroud Gewig Dié teelwaarde is n aanduiding die dier se genetiese groeivermoë tot op een jaar ouderdom. Let asseblief op dat jaargewig n funksie is van voor- en naspeense groei. Selekteer bulle met gemiddelde tot effe bogemiddelde jaargewig teelwaardes vir gemiddelde grootte diere Maande Gewig Dié teelwaarde is n aanduiding van die dier se genetiese groeivermoë tot op 18 maande ouderdom. Dit is ook tot n sekere mate n aanduiding van die dier se volwasse gewig. Soos jaargewig, is 18 maande gewig ook n funksie van voor- en naspeense groei. Selekteer bulle met gemiddelde tot effe bogemiddelde 18 maande gewig teelwaardes vir gemiddelde grootte diere. - Volwasse Gewig Dié teelwaarde is n aanduiding van die dier se genetiese vermoë vir volwasse gewig. Gewigte van koeie 4 jaar en ouer by speen van hulle kalwers word gebruik vir die beraming van volwasse 50 BBE EEF FM A SST TE ER R

21 B E E F M A S T E R

22 52 B E E F M A S T E R

23 EFFICIENCY - Feed conversion ratio (FCR) This EBV is an indication of the genetic ability of the animal to efficiently convert feed into body weight, as measured in Phase C growth tests. Please note that animals with a low FCR EBV are more efficient. Select bulls with low breeding values for efficient feed converters. - Kleiber Ratio This EBV is an indirect indication of the animal s genetic ability for feed conversion efficiency, as measured in Phase D growth tests. Animals with a higher breeding value are more efficient. Select bulls with above average Kleiber Ratio EBVs for good growth efficiency. - Feed Intake This EBV is an indication of the genetic ability of the animal for daily feed intake, as measured in Phase C growth tests. Animals with a high ADG EBV and a low feed intake EBV are more efficient and therefore desirable. - Feedlot Profit Index This EBV is an indication of the genetic ability of the animal to be profitable in a feedlot or similar environment. The EBV is a selection index that is composed of breeding values for feed intake, beginning weight and end weight, taken into account the relative economic weights of each. BODY MEASUREMENTS - Shoulder Height This EBV is an indication of the genetic ability of animals for shoulder height, as measured in Phase C and D growth tests. Select bulls with average shoulder height breeding values for medium frame type animals. - Body Length This EBV is an indication of the genetic ability of the animal for body length (measured from the shoulder bone to the pin bone), as measured in Phase C and D growth tests. Select bulls with above average body length breeding values and average shoulder height breeding values for relatively long animals. CONCLUSION Because EBVs are a combination of an animal s own performance, his relatives (pedigree) performance and the performance of his offspring in a single figure, it is a very accurate and very powerful tool in the hands of a breeder. Fast genetic progress can be obtained with the purposeful and balanced use of EBVs, without adverse effects on other traits. Worldwide, there is sufficient evidence to substantiate this claim. The question is: Do you do performance testing and use breeding values to your advantage? gewig teelwaardes. Selekteer gemiddelde volwasse teelwaardes vir gemiddelde grootte diere. - Gemiddelde daaglikse toename (GDT) Dié teelwaarde is n aanduiding van die dier se genetiese vermoë vir naspeense groei, soos gemeet in Fase C en D groeitoetse. DOELTREFFENDHEID - Voeromsetverhouding (VOV) Dié teelwaarde is n aanduiding van die genetiese vermoë van die dier om voer doeltreffend om te skalel na liggaamsgewig, soos gemeet in Fase C groeitoetse. Let asseblief op dat diere met n lae VOV teelwaarde meer doeltreffend is. Selekteer bulle met lae VOV teelwaardes vir doeltreffende voeromsetters. - Kleiberverhouding Dié teelwaarde is n indirekte aanduiding van die dier se genetiese vermoë vir voeromset doeltreffendheid, soos gemeet in Fase D groeitoetse. Diere met n hoër teelwaarde is meer doeltreffend. Selekteer bulle met bogemiddelde Kleiberverhouding teelwaardes vir goeie groeidoeltreffendheid. - Voerinname Dié teelwaarde is n aanduiding van die genetiese vermoë van die dier vir daaglikse voerinname, soos gemeet in Fase C groeitoetse. Diere met n hoë GDT teelwaarde en n lae voerinname teelwaarde is meer doeltreffend en dus wenslik. - Voerkraal Winsindeks Dié teelwaarde is n aanduiding van die genetiese vermoë van die dier om winsgewend te wees in n voerkraal of soortgelyke omgewing. Die teelwaarde is n seleksie-indeks wat saamgestel word uit teelwaardes vir voerinname, begin gewig en eind gewig, in ag genome die relatiewe ekonomiese gewigte van elk. LIGGAAMSMATES - Skouerhoogte Dié teelwaarde is n aanduiding van die genetiese vermoë van die dier vir skouerhoogte, soos gemeet in Fase C and D groeitoetse. Selekteer bulle met gemiddelde skouerhoogte teelwaardes vir mediumraam tipe diere. - Liggaamslengte Dié teelwaarde is n aanduiding van die genetiese vermoë van die dier vir liggaamslengte (gemeet van voor die skouerbeen tot agter die sitbeen), soos gemeet in Fase C and D groeitoetse. Selekteer bulle met bogemiddelde liggaamslengte teelwaardes en gemiddelde skouerhoogte teelwaardes vir relatief lang diere. Slot Omdat teelwaardes n dier se eie prestasie, sy verwantes (stamboom) se prestasie en die prestasie van sy nageslag in n enkele syfer kombineer, is dit n baie akkurate en baie kragtige instrument in die hand van n teler. Met die doelgerigte en gebalanseerde gebruik van teelwaardes kan vinnige genetiese vordering verkry word sonder negatiewe gevolge op ander eienskappe. Daar is wêreldwyd talryke bewyse om hierdie aanspraak te staaf. Die vraag is: Doen jy prestasietoetsing en gebruik jy teelwaardes tot jou voordeel? B E E F M A S T E R

24 CMW 54 BBE EEF FM A SST TE ER R

25 B E E F M A S T E R

26 56

27 Back to basics the because it s all in genetics ANINA VAN VUUREN Petana Beefmasters Genetics has long been the basic principle on which every stud or commercial breeder builds his business, on purpose or intuitively. They breed their stock, crossbreed, mate, do corrective mating and generate various performance indexes that measure traits that are of interest to them and that are utilised as tools in selection criteria. All in an effort to produce superior progeny or capture specific traits that give their herd an advantage and to stay competitive in the ever developing marketplace. They use indexes to make informed management decisions or inform prospective buyers regarding specific traits of individual animals. They further simply use the selected traits of the animal they see in front of them (or in the world of genetics described as the phenotype of that animal). Conventional performance indexes are irreplaceable tools. However, the unique but fixed genetic makeup of any given individual contributes only half of its outcome while the rest is determined by the environment of that individual. Thu s the influence of factors such as food availability or even disease determine how genetic traits are manifested. Breeders further need to invest in an animal for long periods of time while it is growing to maturity and producing offspring before breeding indexes can be generated, thu making it sometimes an uncertain investment. The advances of now commercially available but still fledgling technology and the advanced indexes generated from these analyses enable breeders to see the genetic profile of animals. Or at this stage at least some of it. This is called genomics and various articles about genomics have lately been seen in the popular press. This topic has also been discussed in the Beefmaster Journal of The benefit of genomics is that it will enable breeders to compare important traits across breeds but also between herds and individuals across different environmental boundaries. Secondly, indexes for specific and important traits can be generated in young non-breeding animals. Genomics is still a very complicated and costly affair and much more genetic data needs exploring but it is an imperative emerging tool to breeders. The subject terminology associated with genetics and genomics however is worth reviewing. Herewith then a short but basic summary of Genetics 101 (for mammals) (specially for all of those that attended Oom Gert se plek rather than their genetic practical across the street on Friday afternoons at TUKS). B E E F M A S T E R

28 GENETICS Classical Evolutionary Mitosis Meiosis Rules of inheritance Chromosomal mapping Molecular Cytogenetics Structure of DNA Control of gene expression Mechanisms of change Change in gene frequansies in populatios Cells are the building blocks All organisms are composed of cells which are fundamental structural units that house genetic material and the biochemical organisation that accounts for the existence of life. Different cells shows tremendous diversity in structure and metabolic capabilities, yet the similarity among these diverse cell types are more profound than the differences. Some of the main properties in common are the following: 1. All cells store information in genes made of DNA. 2. The genetic code used in the genes of all cells is, with minor exceptions, the same. 3. All cell types decode the genes in their DNA by an RNA system that translates genetic information into proteins. 4. Proteins governs function and structure in all cells. Animals such as mammals are composed of about 200 different cell types. Each type has become specialized during embryological development to perform a particular function in one of the many tissues of the animal. Stem cells are undifferentiated tissue cells that can become any type of specialized cell and is used in modern day medical applications such as cell replacement therapy. Stem cells are for example harvested from the embryonic cord of a newborn. Where are those genes? Higher organisms are eukaryotes (as appose to prokaryotes) which means that they have a true nucleus and the genetic material is separated from the remainder of the cell contents by a nucleur envelope. The cytoplasm also contains various other cell structures within a plasma membrane. The chromosomes within the nucleus of the cell structure is normally spread out or diffused but will become thick and structured ONLY during cell division stages (mitosis & meiosis) by processes of coiling and shortening (and the nucleus membrane dissolve). The familiar picture of paired chromosomes is a karyotype and is photographed during mitosis. Similar (homomorphic) chromosomes pairs can be identified (autosomal). However, the different pairs of chromosomes differ in size. A potential exception is the sex chromosomes (XY) which in some species are of unequal size (heteromorphic). Females are XX while males are XY. Figure 1: The karyotype of a human male (XY). Note the difference in size of the last pair of chromosomes; X being the larger and Y the smaller. What are the patterns of inheritance? Genes are located on the chromosomes and is responsible for the expression of specific traits. Their position (loci) and order on the chromosome can be mapped through a complicated laboratory processes. The genotype of an organism refers to the genes it possesses. The phenotype refers to the observable traits and attributes of an organism. 58 B E E F M A S T E R

29 B E E F M A S T E R

30 60 B E E F M A S T E R