3rd World Congress on Genetics Applied to Livestock Production

Selection Applied in the Angus Breeding Scheme of the New Zealand Land Development and Management Corporation

G. B. Nicoll — Mon, 14 Nov 2011 07:45:23 PST

The Land Development and Management Corporation (LDMC) has estabished an open-nucleus Breeding Scheme within its Rotorua District to breed Angus bulls to cover 20 750 cows and 5 200 heifers. Nucleus herd numbers over the 1976-85 period were 775 cows and 357 heifers, with an average of 101 2-year-old bulls being distributed annually to LDMC herds. From 1976/77, a multiplicative breeding objective was established in the nucleus, accounting for cow and calf weights and net fertility of the cow. Primary selection was applied to yearling bulls and heifers using a selection index combining the calf's data and dam's updated data ('Yearling Index', YI). For calves born in 1976 to 1984, the average generation interval was 3.76 years. The corresponding cumulative selection differential for YI had reached 1.90σ in the final year, with similar values also for three of four component traits. For young males, the actual selection differential for YI was 1.47σ, 86% of the maximum possible. The selection applied in this industry Scheme was comparable with that recently reported in two large long-term experimental selection herds of beef cattle.

REPRODUCTION ABILITY OF RECIPROCAL CROSSBREED Fl GENERATION BY ,t· SHEEP OF MUTTON MERINO OF GERMAN TYPE AND BY RAHS OF THE BREED KENT /ROMNEY MARSH

Bora Cumlivski — Mon, 14 Nov 2011 07:40:52 PST

Using the initial breeds which have been followed since 1970 we are creating a Czech Merino Breed with utility combined of fertility, meat, woll and milk, which might be suitable for conditions in Central Europe.

Preliminary Results on Fertility, Prolificacy, Lamb Production, and Carcass Traits of Romanov Sheep in Canada

Mohamed Hamed Fahmy — Mon, 14 Nov 2011 07:37:56 PST

Performance of 14 ewes imported from France and their progeny born in Canada over a period of five years are reported. Least-squares means for fertility were 100% for ewes mated in the fall and winter and 42% for those mated in the summer (May - June). Litter size at birth (2.86 ± .15) and at weaning (2.10 ± .15) were significantly affected by season of mating and parity. The most prolific matings were those of the fall (3.18) and of ewes in their 5th parity (3.54). On the average .52 (18.2%) lambs died at birth and a further .25 (8.7%) before weaning. In all, 27% of the lambs born died before weaning. Mortality was particularly high in the first year (40%). Litter weight averaged 7.1 kg at birth total, 6.0 kg alive and 39.0 kg weaned. Romanov carcasses dressed between 43 and 46%; they were slightly shorter and less developed in the hind quarters than the Suffolk carcasses. Significant differences were found between castrated and non-castrated Romanov lambs, particularly in traits related to fat deposition and area of loin-eye muscle. The results showed that the Romanovs adapted well to the Canadian conditions.

PERFORMANCE RECORDING FOR MERINO SHEEP IN AUSTRALIA (WOOLPLAN)

R. P. Lewer et al. — Mon, 14 Nov 2011 07:34:10 PST

Merinos are the predominant sheep breed in Australia, accounting-for about 76% of a total of 150m. Approximately 197,000 Merino rams are sold annually, of which 157,000 are horned and 40,000 are polled.

The Australian Merino is above all a producer of premium quality white wool. The major determinant of wool income is weight, but the price per kilogram is influenced mainly by fibre diameter.

Recording in Merino stud flocks is minimal. Sires are sometimes identified but dam identities are not routinely recorded. Neither are required for registration purposes. Subjective grading of breeding stock is still the main selection criterion, but there is an increasing emphasis on wool testing data.

Several past attempts to design and establish recording services aimed at flocks with some pedigree information have been largely ignored by Merino breeders. However, successful testing services based on fibre diameter measurement and either greasy or clean fleece weights have been set up by some of the State Departments of Agriculture, the Australian Wool Testing Authority, the School of Wool and Pastoral Sciences (Univ. of N.S.W.) and by private consultants and are well supported. WOOLPLAN is an attempt to rationalize and integrate testing services and extend them to incorporate the recording requirements of studs producing rams for commercial flocks in which wool is an important, though not the sole, source of income.

OPTIMIZATION OF A SELECTION SCHEME FOR MILK COMPOSITION AND YIELD IN MILKING EWES : Example of the Lacaune Breed

F. Barillet et al. — Mon, 14 Nov 2011 07:30:02 PST

Management of the genetic improvement of milking ewes depends: on the obvious fact that they are both dairy animals and sheep. This paper deals with the Lacaune breed situation in France. It paints out the way to build the selection scheme,on two particular aspects:the need to rationalize and simplify milk recording both for milk composition and milk yield, and the concurrent use of AI and natural mating, within the scope of a pyramidal management of the population. We sum up the main results of studies on these different aspects in this paper. In the course of the last twenty years,phenotypic and genetic improvement for the nucleus and base flocks agrees with these theorical studies.

MILK AND BEEF PRODUCTION IN TROPICAL ENVIRONMENTS

V. K. Taneja et al. — Mon, 14 Nov 2011 07:26:44 PST

Cattle breeds native to tropics are late maturing and poor producers of milk and beef, but have the ability to survive under harsh tropical environments. In spite of large, genetic variability for milk yield. selection for productive traits would not be effective in bridging the gap between requirements of human food and its availability. Other methods to achieve these goals have been suggested. Breed comparison studies are needed to identify special genes for fast growth, efficient breeding and resistance to diseases and drought capacity, alternatives like replacement of native with improved European breeds and gene transfer through crossbreeding have been discussed. The results of various crossbreeding experiments in the context of [i] importance of native breeds in crossbreeding. [ii] relative superiority of improver breeds used. [iii] optimum levels of improver inheritance and [iv] effects of inter-breeding among crossbreds have been examined. The success and future of the new developed breeds from crossbred foundations in the changing socioeconomic conditions has been discussed. Larger proportions of Holstein genes in crossbreds has been suggested. Crisscross breds and stabilised crossbreds are on increase for beef production. Feed lot technology offers a great potential for increasing beef production using agro-industrial by-products not fit for human consumption.

Male Heterosis Effect on Lamb Production Traits of the Ewe

T. S. Ch'ang et al. — Mon, 14 Nov 2011 07:20:48 PST

In a CSIRO Sheep Heterosis Experiment, 387 F₁ ewes were mated to either purebred, F₁ or F₂rams for studying the effect of male heterosis on several lamb production traits and to investigate pro rata retention of male heterosis based on the dominance hypothesis. Evidence was found to demonstrate the occurrence of a moderate effect due to the F₁rams (versus the purebreds) and the dominance hypothesis appeared adequate to account for the pro rata retention i.e. at 50%, of heterosis in the F₂rams.

IMPACT OF INDUSTRY STRUCTURE, INTENSITY OF PRODUCTION and RESOURCE CONSTRAINTS ON RESEARCH BREEDING OBJECTIVES

J. W. Wilton — Mon, 14 Nov 2011 07:17:21 PST

The importance of the structure of the beef industry with respect to crossbreeding programs and division into cow-calf and feedlot segments; intensity of production with respect to market standards, feeds and labour; and resource constraints with respect to feed, labour, land and capital; are discussed and quantified where possible. The use of discounted gene flow provides estimates of relative expression rates which differ with crossbreeding programs and relative sizes of populations of purebred and commercial cattle. The importance of feedback from feedlot to cow-calf to purebred operation is emphasized, for both discounted expression rates and modelling approaches. The composition and quality of beef marketed, the influence of energy availability for cow herds and energy density of feedlot diets, and the level of management are discussed as important components of modelling beef production. The impact of resource constraints is discussed and an example is presented which shows the changes in selection decisions caused by changes in constraints. The situations under which selection decisions using linear programming would equal those from the use of a single equation to estimate breeding value for total merit are identified, as are some of those in which selections would differ. The implications of these differences in establishing breeding objectives are discussed.

HETEROSIS FOR PREWEANING TRAITS IN DEVON-HEREFORD CROSSES UNDER TEMPERATE RANGE CONDITIONS

A. L. Gyles et al. — Mon, 14 Nov 2011 07:14:19 PST

Heterosis for gestation length. birth weight. suckling stimulus. weaning weight and preweaning growth was estimated from the first years data of a complete two-breed diallel with the Devon and Hereford breeds. involving 119 calves by 29 sires grown together under temperate grazing conditions at Gunnedah. New South Wales. Australia.

Estimates of heterosis (and average mid-parent values) for gestation length were 0.2% (282.9 days); birth weight 6.5% (32.6kg); suckling stimulus 22.9% (3.51/day); weaning weight 5.9% (155.1kg); and average daily gain to weaning 7.0% (0.6kg/day).

GENETIC VARIABILITY AND SIRE X MATING SYSTEM INTERACTION FOR MILK YIELD IN HOLSTEIN-SAHIWAL CROSSES

V. P. Rao et al. — Mon, 14 Nov 2011 07:09:27 PST

The average first lactation milk yield of crossbreds in northern region was higher than that in southern region with heritability estimates being 0.16±0.06 and 0.04 ± 0.04. The heritability estimates according to production level were 0.28 ± 0.14, -0.02 ± 0.04 and 0.36 ± 0.15 for low, medium and high level herds in northern and -0.05 ± 0.01 and 0.03 ± 0.12 for low and high level herds in southern region,suggesting more genetic viability in relation to total variance in high level herds. The reasons for low estimates in medium level herds have been discussed. The sire x genetic group interaction was estimated from (i) two way analysis of variance" and (ii) genetic correlation between the same trait expressed in two genetic groups. The sire x genetic group interactions were non-significant and the genetic correlations were 0.87 and 1.00 in northern and southern region, respectively. The sire x breed of dam interaction was non-significant for all breed group combinations.

GENETIC TREND IN MILK YIELD OF EXOTIC CATTLE IN INDIA

D. K. Sadana et al. — Mon, 14 Nov 2011 07:03:35 PST

For the purebred exotic cattle in India the phenotypic and genetic trends were estimated. While the phenotypic trends were positive for all the four farms, the genetic trend was found to be negative for three and positive for one. This necessitates a higher emphasis on progeny testing and sire selection for the improvement of the imported breeds.

GENETIC PREDICTION FOR BEEF IN UNITED STATES

R. L. Willham — Mon, 14 Nov 2011 07:01:16 PST

Beef performance programs have come a long way since their start after World War II as a means of within-herd improvement. Now performance programs can be used to rank young animals on all the available information across all the herds of a breed. Opportunity exists to design and conduct performance programs that can be used to promote the breed, enhance management decision making, and make real genetic change in the breed.

GENETIC PARAMETERS FOR GESTATIOB LENGTH, BIRTH DATE AND TIME TO FIRST OBSERVED ESTRUS IB BEEF CATTLE

Sara Melin Azzam et al. — Mon, 14 Nov 2011 06:59:01 PST

Genetic and environmental variability in gestation length (GL), birth date (BD), and time from first day of breeding season to first observed estrus (FE) were analyzed ·using twelve years of breeding and calving records on cows, sired by Simmental, Maine-Anjou, Limousin and Gelbvieh bulls. All cows were artificially inseminated. Statistical analyses were performed separately on first, second and last parity records. Paternal half-sib estimates of heritability for GL as a trait of the calf were between .36 and .45 while the estimates for BD were between .09 and .24. The estimates of heritability for FE, treated as a trait of the cow, were less than .10. Heritabilities for maternal additive effects were small for GL and BD. The correlation between direct and maternal additive effects were negative for GL and BD in parity 1 and for GL in parity 2. The expected annual responses to selection on an index that maximizes the sum of the direct and maternal breeding values were .76 d and 1.03 d for BD and GL, respectively.

GENETIC DIVERGENCE IN COMPONENT STRAINS OF KARAN-FRIES CATTLE

R. K. Sethi et al. — Mon, 14 Nov 2011 06:54:46 PST

Data on 50 percent and higher Holstein Friesian crossbred genetic groups revealed significant differences with respect to age at first calving, first lactation 305 days yield, dry period and service period. 91.7 percent of the divergence among genetic groups was contributed by 305 days lactation yield. F₁ crossbreds formed separate cluster. Among the higher crosses (75% and above) genetic groups involving only 2 breeds formed separate cluster from genetic groups involving three breeds. Three breed cluster was farthest from the F₁ crossbreds cluster. There was an indication of all the clusters having animals of good genetic potential.

EVALUATION OF INDUSTRY BREEDING PROGRAMS FOR SHEEP AND GOATS INTRODUCTION AND OVERVIEW

J. N. Clarke — Mon, 14 Nov 2011 06:47:38 PST

In his introduction to the Plenary Session of the First World Congress on Genetics Applied to Livestock Production for Sheep, Rae (1974) pointed to the wide diversity of sheep production systems throughout the world. Goats add further to this range in production environments, husbandry systems and to the variety of products for which these two domestic species are farmed. Such variety makes any consolidated review of Genetic Improvement Programs for sheep and Goats very difficult, especially if all important operational features of ~e production and marketing circumstances for each end product are to be considered in evaluating the success of programs currently being applied around the world. For this reason a decision was made in planning this Session not to attempt the difficult task of reviewing in-depth all those applications of genetic improvement for which published information is available. Rather, it was decided to attempt to draw out the different ways in which breeding programs may be evaluated, giving emphasis to the sort of approaches that have been taken. Because this format would need to refer to specific examples it was considered that these could be chosen to illustrate particular operational features and genetic principles upon which different programs are based. It was also considered that this format would prevent some repetition of descriptive detail already published and that it would provide greater operational insight by highlighting actual applications appropriate to different species, breeds and traits as well as to the production circumstances under which animals were managed. Throughout this review, genetic improvement is confined to the application of selection, there being a separate Plenary Session of the Congress devoted to Evaluation and Utilisation of Breed Resources through crossbreeding. Other mating plans are also ignored, such as from an inbreeding point of view (Rae 1981), but not from the point of view of applying selection in sire-breeding flocks and especially in the nucleus flocks using elite matings for sire production. These aspects are an important feature of the second review paper by NICOLL et al., which considers inter-flock relationships for application of genetic improvement in a population as a whole rather than only in terms of genetic progress for an individual flock. The latter details are the subject of the first review paper by ATKINS et al..

EVALUATION OF INTER-FLOCK GENETIC IMPROVEMENT PROGRAMS FOR SHEEP AND GOATS

G. B. Nicoll et al. — Mon, 14 Nov 2011 06:41:08 PST

Some of the factors involved in inter-flock or breed improvement programs are discussed. Such programs are complicated by the fact that sheep and goats produce a wide range of products under diverse environmental, management and economic circumstances. This leads to problems in defining realistic breeding objectives arising from determining the beneficiaries of genetic improvement, the major genetic decision makers in the industry and the relative importance of the various productive characteristics. The implementation of functional performance recording systems, breeding systems to generate young sire replacements, and testing systems to disseminate genetic improvement, also depend on the conditions under which the breeding programs operate. Alternative means of estimating genetic improvement in breeding programs through comparisons of progeny by sires repeated over time or from parents of different ages, and the use of artificial insemination (AI), multiple ovulation and embryo transfer (MOET) and mixed model methodology (BLUP) are also briefly addressed.

EVALUATION OF INDUSTRY BREEDING PROGRAMS FOR DAIRY CATTLE MILK AND MEAT PRODUCTION

Franz Pirchner — Mon, 14 Nov 2011 06:37:40 PST

In most European."dual purpose breeds beef merit is paid attention to by selection among performance tested bulls where comparatively much weight is given to growth rate of performance pasted bulls and relatively little weight to muscling and thus to carcass meat content. The genetic correlation between beef and dairy merit appears to be negative. This, in combination with large ad effective selection pressure on milk leads to negating the effects of the little and relatively inaccurate selection for beef merit at the best. Field progeny testing for beef merit can be economical and will permit to neutralize or even improve the beef merit of dual purpose cattle without much reduction in genetic progress of dairy merit.

In dual purpose cattle breeds milk and meat are of roughly equal importance, i.e. the minor trait should not contribute less than some 20 - 25 % to the total income. The selection objectives for dairy traits are clearly defined and there exists a close correspondence with selection criteria such as lactation or part lactation yield.

The selection objective in case of beef production is the quantity of lean meat or the efficiency of lean meat production. However, the selection criteria are numerous and they need to be included in fairly complex prediction equations. Frequently their commercial relevance is not obvious. Also, prospective feeder animals are usually marketed very early - frequently at an age of one week - where the fattening quality can be poorly appraised and no or little price differentiation is practized.

Milk and Beef Production in Temperate Climates

A. Zarnecki et al. — Mon, 14 Nov 2011 06:28:58 PST

Milk production in the temperate climates accounts for 66% of the world milk output. In North America only about 20% of beef originates from dairy herds, while in Europe beef production is a byproduct of dairying. Several studies showed small genetic correlations between milk and beef traits, thus suggesting the possibility of simultaneous selection for both .characteristics. European breeding programs include dual testing of bulls for milk and beef. Several experiments proved superiority of North American Holstein- Friesians over European dairy breeds in milk production. In the Polish Friesian strain comparison, the US strain, the Canadian strain and the Israeli Friesians produced 19%, 16% and 16% more milk, respectively, than the Polish Black and White strain. In fat yield New Zealand ranked together with Holsteins. The main disadvantage of crossing European breeds with North American dairy cattle is poorer beef quality. Further improvement of specialized dairy breeds is expected in North America. In Europe, the introduction of a milk quota system and the necessity of maintaining beef production may require re-assessment of current breeding strategies.

Genetic Engineering of Livestock Improvement

Gordon E. Dickerson — Mon, 14 Nov 2011 06:22:17 PST

Genetic engineering requires clearly defined objectives, adequate genetic variability and effective methods of selection. In a given production-marketing System, relative importance of genetic change in alternative traits can be estimated from expected effects on cost per unit of output, using available biological and economic information. Diversity among existing breeds and their crosses is a primary and quickly usable genetic resource, and its management for future needs is a public concern. Better physiological and biochemical understanding of the genetic controls of animal development and function is important to permit more effective selection for efficiency of animal production under diverse environments. Long-term selection experiments indicate gene numbers, limits of response, the role of natural mutations and pleiotropic associations among traits. New reproductive technology permits more intense selection among females and promises effective new nuclear breeding systems. New techniques for manipulating bits of DNA also stimulate many questions about potential applications in animal breeding. All of the above, provide background for critical evaluation of industry breeding programs, which also involves educational and organizational efforts. Contributions from all specialties within the animal breeding fraternity, as well as from our colleagues in related disciplines, are needed for continued progress in livestock improvement.

Heterosis on Body Weights in Crosses Among Brahman, Santa Gertrudis and Cheju Native Cattle

D. H. Baik et al. — Wed, 28 Sep 2011 07:40:05 PDT

Data obtained from 428 calves (59 Cheju native cattle, 60 Brahman, 40 Santa Gertrudis and 269 crossbreds) were analyzed to estimate main effects of environmental factors and heterosis. Mating type, sex of calf, and year of birth were significant sources of variation on most of the weights at preweaning and postweaning periods. Brahman x Cheju native cattle cross showed heterosis of 6.1% on birth weight. Maternal heterosis on weaning weight was 4.9% in Brahman back-crosses and 12.3% in Santa Gertrudis backcrosses.