Life Sciences Commons^™

Economic Evaluation Of Breeding Objectives For Beef Cattle, C. A. Morris

3rd World Congress on Genetics Applied to Livestock Production

Defining breeding objectives for beef cattle is a difficult task, especially for cattle under extensive grazing, as described by the authors in this Session. In considering economic aspects, Wilton points out the poor feedback among different sectors of the industry (such as among cow-calf producers, store cattle farmers and finishing operators; also between commercial and pedigree herds). Farmers with different breeds contributing to crossbred cattle also appear to receive poor market signals.

Development Of A New Synthetic Prolific Kine Of Sheep (Inra 401), L. Tchamitchian, C. Lefevre, C. Brunel, B. Bibe, G. Ricordeau

3rd World Congress on Genetics Applied to Livestock Production

After a first comparison of various prolific breeds crossed with Barrichonne du Cherre (BC), successive generations of Romanov × BC crossbreds were studied on experimental flock, in a second comparison. There was no difference among generations F-1 to F-4 regarding essential factors of numeric productivity in ewes. The INRA 401 dam line originated in the resulting population, which has appeared to be stable in main production traits. Since 1980, it has been subjected to a closed flock selection for prolificacy and milk production. Meanwhile, rams have been used on farms for intra-flock replacement of F-1 ewes. There is no difference …

Crossbreeding Of Cattle In Sri Lanka, E. F. A. Jalatge

3rd World Congress on Genetics Applied to Livestock Production

Sri Lanka is an island in the tropics having a cattle population of about 1.7 million. In order to improve the productivity of these animals crossbreeding trials were initiated about 2-3 decades ago.

The indigenous cows were bred to bulls of Jersey, Friesian and Shorthorn breeds. Improted Zebu breeds such as Sindhi and Tharpakar were also bred to bulls of temperate breeds.

The article describes the findings of these experiments and their usefulness in formulating breeding policies for the different agroclimatic zones of the country.

Economic Evaluation Of Breeding Objectives In Sheep And Goats- Summary And Commentary, R. W. Ponzoni

3rd World Congress on Genetics Applied to Livestock Production

At the first and second World Congresses on Genetics Applied to Livestock Production some consideration was given to the definition of breeding objectives in sheep and goats. Having a whole Plenary Session dedicated to the evaluation of breeding objectives at the present Congress is an indication of the greater awareness about the importance of this area in the overall efficiency of breeding programmes. the chances of success of a breeding programme will be enhanced if during its formulation the following five steps are taken in meticulous order: (i) definition of the breeding objective; (ii) choice of selection criteria; (iii) organisation …

Economic Evaluation Of Breeding Objectives For Sheep And Goats: Practical Considerations And Examples, G. E. Bradford, H. H. Meyer

3rd World Congress on Genetics Applied to Livestock Production

Examples of breeding objectives for sheep industries with well developed breeding programs such as in Australia and New Zealand are reviewed briefly. For industries lacking adequate information on genetic and economic parameters to quantify objectives precisely, some general guidelines for choice of objectives are outlines, and it is suggested that considerable genetic progress can be made in such industries by use of sound objective in choice of breeds, breed combinations or base populations for multiplication. Objectives which it is suggested merit increased attention include: (1) defining optimum litter size and mature size; (2) improving lamb viability; (3) improving longevity and …

Economic Evaluation Of Breeding Objectives In Sheep And Goats - General Considerations, J. W. James

3rd World Congress on Genetics Applied to Livestock Production

The procedures to be followed and some of the problems which arise in defining breeding objectives are discussed. Special emphasis is given to attempts to reconcile conflicts between different bases of evaluation, and it is concluded that from a long-term viewpoint, efficiency should be the goal of the breeder, where efficiency is measured as the ratio of the value of all inputs to the value of all outputs. In the shorter term, or where artificial distortions of markets occur, other objectives may be preferred. Goals should be clearly distinguished from selection criteria, and this will be more likely to be …

Comparison Of Reproduction Ability Of The So Called "World" Fertile Breed Of Sheep In Large And Small Concentrations, Bora Cumlivski

3rd World Congress on Genetics Applied to Livestock Production

To ascertain reproductional abilities of the following imported fertile breeds: Romanov/from USSR/, Finnish/Finland/, Eastfriesian/GDR/ reared and kept in Large and small concentrations.

Evaluation And Utilization Of Breed Resources - Sheep And Goats, R. L. Baker

3rd World Congress on Genetics Applied to Livestock Production

I believe just a few brief introductory remarks to this plenary session are needed. We are discussion three distinct topics in this session and the reason for choosing them warrants some brief comment.

In the plenary session on Sheep and Goat Genetics and Breeding at this conference in Madrid in 1982 there were two papers relating to breed evaluation and utilization. Dr. Alan Quartermain discussed the utilization of breed resources in the improvement of goat productivity, while Dr. Neil Clarke comprehensively reviewed utilization of breed resources in the improvement of sheep productivity.

Empirical Validation Of The Dominance Model For Beef Cattle, D. D. Kress, D. E. Doornbos, D. C. Anderson

3rd World Congress on Genetics Applied to Livestock Production

Data from 770 records of Hereford, 25% Simmental - 75% Hereford, 50% Simmental - 50% Hereford and 75% Simmental - 25% Hereford cows were used to evaluate whether breed group means for maternal traits agreed with expectations based on the dominance model. Cows were managed consistent with practices for western range environments. Cow breed group was significant for 17 of the 18 traits studied. The measure of goodness of fit of the breed group means to the dominance model was the R² value associated with the linear regression of breed group means on proportion of Simmental for the first …

Estimation Of Genetic Relationships Among Milk Records For First Three Lactations Using Reml For An Animal Model, H. H. Swalve, L. D. Van Vleck

3rd World Congress on Genetics Applied to Livestock Production

In dairy cattle breeding, genetic relationships among lactation records are of special interest because most selection operated on first lactations. This selection also complicates estimation of genetic parameters. Techniques which give estimates unbiased by selection should be used. Estimation was done using EM-type REML for an animal model neglecting relationships across herds. Records were from 3,070 Holstein cows which had the fist lactation recorded. Estimates after 17 rounds of iteration for heritabilities and genetic correlations were: h²₁=.33, h²₂=.32, h²₃=.33, r₁₂=.88, r₁₃= .83, r₂₃= .86. Within …

Embryo Transfer: Economic Implications For The Dairy Industry, J. S. Barr, D. C. Huffman, R. A. Godke

3rd World Congress on Genetics Applied to Livestock Production

Developments in nonsurgical embryo transfer have made commercial application for beef and dairy cows feasible. DHIA records were used to determine milk production variability within dairy herds. The top 10 percent of cows within herds produced 43 percent more milk that the herd average compared with 49 percent below herd average for the bottom 10 percent. The top 10 percent of cows within DHIA herds were assumed to be embryo donors for the remainder of the cows in DHIA herds. Economic implications were assessed for the U.S. dairy industry by region. Feed required to support the higher milk production level …

Evaluation Of Crossbreeding Systems For Preweaning Traits In Beef Cattle, M. D. Macneil, L. V. Cundiff, K. E. Gregory, University Of Nebraska-Lincoln

3rd World Congress on Genetics Applied to Livestock Production

Data from a four-generation crossbreeding experiment with Hereford, Angus and Shorthorn cattle were analyzed. Individual, maternal, and grand-maternal additive and heteroic effects on the composite trait of calf weight weaned per cow exposed to breeding and its component traits were evaluated. The parameter estimates were than used to project performance at equilibrium under rotation crossbreeding. The average of two-breed cross rotations is expected to increase calf weight weaned per cow exposed by 18 percent above the average of the three straight breeds. The three-breed cross rotation is expected to increase calf weight weaned per cow exposed by 23 percent above …

Evaluation And Utilization Of Tropical Breeds For Efficient Beef Production In The Tropics: Challenges And Opportunities, Assefaw Tewolde

3rd World Congress on Genetics Applied to Livestock Production

Crossbreeding results between tropical breeds and European beef breeds as well as within breed (mainly Zebu) genetic variability for some economically important traits is reviewed. Heterosis of between 9% to 11% has been reported for preweaning growth rate, 2% to 11% for postweaning and carcass traits as well as up to 15% for reproduction related traits in crosses involving Bos indicus and Bos taurus cattle. Maximum heterosis was observed in crosses involving Zebu and Criollo cattle, both well adapted to the tropics. Within breed genetic parameter estimates under tropical conditions are still scanty. Based on the production environment and after …

Evaluation Of Beef Cattle Industry Breeding Programs, Keith Hammond

3rd World Congress on Genetics Applied to Livestock Production

A critical evaluation of existing beef cattle breeding programs should include such criteria as: definition of desired genetic changes in performance, breeding value estimation procedures used and accuracy of selection criteria, intensity of selection applied, use of additive differences between breeds and of non-additive variation, maintenance of genetic variability, realised genetic trends and return on investment. Each major production- marketing environment should be treated and correct account take of the industry structure. Such a study would undoubtedly highlight any inadequacies in the essential information. To extend the study to adequately cover all major beef industries would be an enormous task. …

Evaluation Of Beef Cattle Industry Breeding Programs: Breeders And Breed Associations, Robert M. Koch, James B. Gibb, James A. Gosey

3rd World Congress on Genetics Applied to Livestock Production

Seed stock producers, though the smallest segment in the beef industry, are the primary sources of genetic improvement and should be the focal point of national efforts to improve genetic merit. Importation of "new" breeds into North America in the late 1960s and early 1970s increased or broadened the germ plasm base available to the industry. Thew new breeds caused a significant displacement of numbers in the established breeds and added impetus to crossbreeding in the commercial segment. The record of performance movement became a significant factor in seed stock production during the past 25 years and is now an …

Evaluation Of Straight- And Crossbreeding In Beef Cattle In The R.S.A., H. A. W. Venter, J. G. E. Van Zyl, R. J. Coertze

3rd World Congress on Genetics Applied to Livestock Production

Results from various straight- and crossbreeding trials conducted in South Africa were reviewed. The conclusion is drawn that in some instances, initial crossbreeding followed by inter se mating of crossbred cattle give the same if not better results than continued crossbreeding. This facilitates rangeland improvement as it limits the number of pastures needed during the breeding season.

Evaluation Of Nelore, Canchim, Santa Gertrudis, Holstein, Brown Swiss And Caracu As Sire Breeds In Matings With Nelore Cows. Effects On Progeny Growth, Carcass Traits And Crossbred Productivity, A. G. Razook, P. R. Leme, I. U. Packer, A. Luchiari Filho, R. F. Nordos, J. B. Trovo, C. N. Z. Capelozza, F. L. Pires, J. Nascimento, C. Barbosa, J. L. B. Coutinho, W. J. Oliveira

3rd World Congress on Genetics Applied to Livestock Production

Over three calf crops, 1096 exposures of 380 Nelore (a Zebu breed) cows to 6 sire breeds Nelore (N), Canchim (C), Santa Gertrudis (G), Holstein (H), Brown Swiss (S), and Caracu (K), resulted in 644 calves weaned for a 63% calving rate. Sire breed effect was significant for birth weight, weaning weight, 13 mo weight and 18 mo weight. HN and SN calves were the heaviest at all weight periods wile CN, GN, and KN calves were the intermediates. Average daily gain from 18 mo to slaughter age was measured in 125 males finished in feed lot and 116 on …

Evaluation Of Dairy Cattle Breeding Programs: Specialized Milk Production, L. D. Van Vleck

3rd World Congress on Genetics Applied to Livestock Production

Milk recording, artificial insemination and computers have given the dairy cattle industry and effective combination of tools for genetic improvement. Selection theory (Robertson and Rendel, 1950) indicates that annual gains of 1.5 to 2.0% of the mean should be possible.

The dairy industry is also fortunate that one trait, milk production (used as a general term for yield of milk, fat and protein), is of primary importance. Another advantage is that no intermediate optimum for milk production is obvious--more and more seems to be profitable--in contrast to the situation for most traits of most livestock.

With these advantages for making …

Breeding Beef Germ Plasm Composites To Fit Special Environments, Gary Conley

3rd World Congress on Genetics Applied to Livestock Production

A long term breeding program has been designed to take advantage of the heterosis available in a six breed composite while developing a cow which can reproduce on crop residue. A controlled natural selection method has been developed for those reproductive traits which did not lend themselves to objective measurement. Reproductive efficiency and feed conversion will always be desirable traits in beef cattle. Intensive selection pressures were applied to the above traits during the initial generations of crossing to form the composite. Culling rates of 70% were used in the initial and backcross generations. The effectiveness of selection has been …

Feed Intake Of Dairy Cows As An Economic Selection Trait, Hans O. Gravert, Klaus Pabst

3rd World Congress on Genetics Applied to Livestock Production

32 pairs of monozygons twins were fed ad lib. with a complete diet feed during the first 20 weeks post partum. The heritablity (in broader sense) for milk yield, feed intake and energy deficit was 0.39, 0.17 and 0.19 resp. the genetic and phenotypic correlations between daily milk yield and feed intake were 0.14 and 0.26 resp. Therefore selection for feed intake should be based on progeny groups of A. J. bulls. To estimate the feed intake under field conditions the content of ketone-bodies in milk at first and second test day p.p. can be combined with the milk yield …

Characterization Of Milk Constituents Of Bos Taurus And Bos Indicus × Bos Taurus Breed Types, Donald R. Daley, Anne Mccuskey, Curtis M. Bailey

3rd World Congress on Genetics Applied to Livestock Production

Milk from eight Bos Taurus and Bos indicus × Bos Taurus breed types (n=128) was evaluated for percentage butterfat, protein, lactose and solids- non-fat. Milk samples were collected at approximately 60, 105, and 150 d after the onset of lactation by hand-milking the left front quarter following a 30-IU injection of oxytocin. Breed type variation was significant for some milk component traits at each stage of lactation. Brahman × Angus dams increased in component yields (kg) as lactation progressed; production levels of other breed types remained approximately the same or declined. Sex of calf influenced (P<.05) yield (kg) of protein, butterfat and solids-non-fat at 105 d only. Mastitis effects caused a reduction (P<.01) in percentage of lactose. Residual correlations between yield (kg) of milk components and weaning weight were all positive and significant.

Feed Intake Specifications In Defining Breeding Objectives, D. R. Notter

3rd World Congress on Genetics Applied to Livestock Production

Development of selection objectives for beef cattle requires consideration of the available feed resources. In production systems with access to liberal quantities of harvested feeds of relatively high quality, selection to improve economic efficiency will normally favor animals with high genetic potentials for the primary production traits. However, these highly productive types may also have relatively high maintenance requirements and be less efficient when nutrient restrictions prevent expression of genetic differences in appetite. This, important genotype × environment interactions may be observed. In range environments, animals may be restricted in the amount of forage that can be harvested. These restrictions …

Genetic Parameters For Subjective Milking Speed Scores, K. Meyer, E. B. Burnside

3rd World Congress on Genetics Applied to Livestock Production

Farmer-supplied subjective ratings of cows milking speed, scored in 5 categories as 'very fast', 'fast', 'average', 'slow' or 'very slow' were analyzed. Scores were affected by herd- year- season of calving, age at calving and stage of lactation when scored but not by test day milk yield. Heritability estimates were 0.21 and 0.14 for scores up to day 110 of lactation for Canadian Holsteins and Ayrshires, respectively, and 0.17 and 0.16 for scores at the end of lactation. The estimate of repeatability of scores for the same cow in different lactations was 0.42 for Holsteins and 0.37 in Ayrishires.

Genetic Engineering Of Livestock Improvement, Gordon E. Dickerson

3rd World Congress on Genetics Applied to Livestock Production

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 …

Genetic Diversity Among Cattle Breeds And Its Use To Increase Beef Production Efficiency In A Temperate Environment, Larry V. Cundiff, Keith E. Gregory, Robert M. Koch, Gordon E. Dickerson

3rd World Congress on Genetics Applied to Livestock Production

Results are reviewed from the cattle Germ Plasm Evaluation Program at the Roman L. Hruska U.S. Meat Animal Research Center comparing performance of top-crosses by 20 sire breeds. The variation that exists in biological traits important for beef production is vast and under a high degree of genetic control. Significant genetic change can result from 1) selection among breeds, 2) use of crossbreeding to exploit heterosis and 3) selection within breeds. Estimates of the range for differences between breed means vary from 2.5 to 6.3 phenotypic standard deviations (σp) and exceed 4σp for most traits. The range for differences between …

Milk And Beef Production In Temperate Climates, A. Zarnecki, M. Stolzman

3rd World Congress on Genetics Applied to Livestock Production

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 …

Genetic Improvement For Milk And Meat Production In The Tropics, N. Künzi, W. Kropf

3rd World Congress on Genetics Applied to Livestock Production

Theoretical and practical ways to improve meat and milk production in the tropics by selection within local Bos indicus breeds, within Bos taurus x Bos indicus composite populations, upgrading of Bos indicus with Bos taurus breeds and though different crossbreeding programs have been discussed by various authors and summarized by Mason and Buvanendran (1982), Gregory et al. (1982) and Hickman (1979). Only few publications (Auriol, 1984; Chacko et al., 1985; Donegan and Roberts, 1984) exist on successful programs but numerous reports in developing agencies (FAO, 1985; SDC, 1985) indicate that many possibilities have been exploited and that various …

Evaluation Of Industry Breeding Programs For Dairy Cattle Milk And Meat Production, Franz Pirchner

3rd World Congress on Genetics Applied to Livestock Production

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 …

Heterosis On Body Weights In Crosses Among Brahman, Santa Gertrudis And Cheju Native Cattle, D. H. Baik, D. C. Kim

3rd World Congress on Genetics Applied to Livestock Production

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.

Genetic Variability Among Cattle Breeds For Beef Production, R. B. Thiessen, C. S. Taylor

3rd World Congress on Genetics Applied to Livestock Production

Between-breed variation in body weight, food intake, carcass composition, milk yield, efficiency of food conversion during growth and maintenance efficiency in adult cattle was examined in a multibreed experiment at the AFRC Animal Breeding Research Organisation. Females from 11 beef , 8 dual-purpose and 6 dairy breeds were fed a complete pelleted diet (AA6) ad libitum from weaning at 12 weeks of age until the birth of their third calf. Females were mated by AI to produce both purebred and crossbred progeny which were reared under the same conditions and slaughtered at either 24, 48 or 72 weeks of age. …