Breeding and Genetics

Want to simplify your breeding records? Check out our special section Focus On: Flock Management Software for more information on a software system being used by many DSANA members. Broken link? Something out of place? Please email hello@dsana.com for assistance!

  • Virtual Tour of a Shepherd’s Creek Dairy Farm – 2019 – Butch Cargile.  A history and virtual tour of Shepherd’s Creek Dairy Farm that discusses their breeding program (including artificial insemination), feed, disease prevention, and economics.

  • Using DSANA’s Production Improvement Program (PIP & EBVs) at Green Dirt Farm – 2019 – Eliza Spertus, Green Dirt Farm.  A presentation on how Green Dirt Farm sheep dairy has used the PIP/EBVs to make culling and breeding decisions that help balance other performance records.

  • Using EBVs for Our Breeding, Selection, and Culling Decisions – 2019 – Quincy Wool Parker, Meadowood Farms.  A presentation on Meadowood Farms’ breeding program and how they collect data for and use EBVs to make breeding decisions.

  • Milk Production Comparisons: Domestic & F-1 Yearlings from the Imported French Semen – 2019 – Laurel Kieffer DSANA Production Improvement Project, Tom Clark DSANA Genetic Improvement Committee, Mike Thonney Professor of Animal Science Cornell University.  A presentation that demonstrates the differences in milk production from the first F1 ewes born from imported French Semen.  It incentivizes both the semen importation program and DSANA’s Production Improvement Program.

  • Using the numbers: How performance recording contributes to genetic gain and economic opportunities in sheep dairying - 2018 - One of the world’s leading sheep geneticists explains the principles of genetic selection, and how performance records can become tools for genetic improvement in dairy sheep operations.  How the heritabilities of desirable traits in dairy sheep, such as milk yield, fat and protein percentages, somatic cell counts, and lactational persistence, can be used to generate EBVs (Estimate Breeding Values).  How genetic gain in these traits can impact farm profitability.  The correlation between changes in milk yield and changes in component percentage.  How to understand, interpret, and apply an individual animal’s genetic evaluation from Genovis.

  • Dairy Sheep genetic improvement project - 2018 - DSANA provides members with performance testing and genetic analysis for their flocks, via milk yield measurements and component sampling, through Genovis’ genetic evaluation service.

  • Current trends of the Spanish Assaf Sheep / Genetic Improvement Program - 2018 - Overview of the genetic improvement of dairy traits in the Assaf breed over the last 25 years.  An intensive selection and breeding program employed by the Spanish Assaf Association has resulted in major improvements in the breed’s milk yield, lactation length, and udder conformation.  The breed improvement program has also included selection for milk composition and somatic cell count.

  • Nutritional Management of Reproduction in Dairy sheep - 2018 - A small ruminant dairy vet and sheep dairy owner in California lays out how to managing ewe nutrition to maximize reproductive efficiency – improving ovulation rate, conception rate, pregnancy to term, and lambing rate.  The relationship of Body Condition Score with reproduction.  The impact of feed characteristics, feed quality, and feed mineral profile on reproduction.

  • Management of AI Reproduction in Dairy Ewes - 2018 - A small ruminant dairy vet and sheep dairy owner in California explains how to improve conception rates for ewes bred via laparoscopic AI.  Specifics on reducing internal and external stressors, from 60d prior to insemination date, to 45d after insemination date.  Handling and management of ewes during LAI process.  Factors that affect semen quality.

  • Update on Sheep Genomics & Genetics - 2016.Christian J. Posbergh & Heather J. Huson. An overview of DNA based tests like genomics & parentage testing. Includes a look at genomic based EBVs and their potential application to dairy sheep.

  • Estimating Breeding Values for Sheep: Estimates of Genetic Parameters & Trends in a Crossbred Population of Dairy Sheep - 2016. Thomas W. Murphy & David L. Thomas. Using the flock & research from the University of Wisconsin Spooner Reasearch Station to look at the basic concepts of a genetic evaluation program, the impact of non-genetic effects on dairy ewe performance and the formulation of estimated breeding values.

  • Implementation of Genetic Evaluation - 2016. George R. Wiggans - Guidelines for utilizing a genetic improvement program as exemplified by the American Dairy Goat Association's model for producing EBV's, includes steps required by the farm and the association.

  • A Genetic Evaluation Program for Dairy Sheep in Canada: Preliminary Results from a Project in Quebec - 2016. Johanne Cameron & Larry Schaeffer. An in-depth look at the development of the Gen-Ovis program, why it exists and it's goals.

  • Effects of Breed and Hybrid Vigor on Lamb Survival - 2015. Vera C. Ferreira, Guilherme J. M. Rosa, Yves M. Berger, and David L. Thomas. A look at the effect of cross-breeding on lamb survival rates and thrivability.

  • Estimated Breeding Values Do Predict Future Performance - 2015. Thomas W. Murphy. An overview of Estimated Breeding Values (EBVs) answering the questions: What are they? How do you use them? And do they work?

  • Biotrack: A Record Keeping System for Dairy and Meat Sheep – 2014 – Terry McNeely.  A presentation on the bioTrack record-keeping program and how it can be applied to dairy sheep to help improve genetics and management practices.

  • Current Regulatory Requirements for Ovine Semen & Embryos - 2012 - Dr. Peter Merrill, Assistant Director, Animal Imports at USDA APHIS. Detailed information on the importation of sheep semen & embryos into the US as of 2012.

  • Performance of Katahdin-Lacaune crossbred ewes - 2012 - Yves Berger & David Thomas, University of Wisconsin, Spooner Research Station. A small research study looking at the feasibility of a hair (Katahdin) dairy (Lacaune) ewe; which combination worked best with the ultimate goal to create a shedding dairy ewe.

  • Genetics of Lamb Survival, 2011, David L. Thomas. A small study of crossbreeding sheep for lamb survival vs purebred and inbreeding.

  • SIRE REFERENCING PROGRAM - 2010 - Claire Mikolayunas, Department of Animal Sciences, University of Wisconsin-Madison. Discussion on creation of a template for milk production records for dairy sheep and genetic merit for ewes and rams

  • MANAGEMENT PRACTICES AT OLD CHATHAM SHEEPHERDING COMPANY - 2010 - Travis Burrows and DaNay Spurge, Old Chatham Sheepherding Co.

  • INDUCTION OF ESTRUS AS A REPRODUCTIVE MANAGEMENT TOOL IN ANESTROUS EWES - 2009 - Keith Inskeep, Division of Animal and Veterinary Sciences, West Virginia University. Study focusing on out-of-season breeding in dairy sheep

  • GENETIC MARKERS FOR MILK PRODUCTION - 2009 - Raluca G. Mateescu and Michael L. Thonney, Oklahoma State University, Cornell University. Knowledge of the genes controlling milk yield, or markers linked to these genes to be used in marker-assisted selection should provide the tools needed to implement effective (more accurate and faster) genetic improvement programs for increased milk production in sheep.

  • THE ISRAELI DAIRY SHEEP INDUSTRY -2008 - Gabriel Leitner National Mastitis Laboratory, Kimron Veterinary Institute. History of the Israeli dairy sheep industry

  • UPDATE ON IMPORTATION OF RAM SEMEN INTO THE U.S. - 2008 - David L. Thomas, Department of Animal Sciences, University of Wisconsin-Madison. Ddiscussion of the importation of ram semen into the US

  • Non-nutritional strategies to improve lactation persistency in dairy ewes - 2005 - Pulina. The ideal lactation curve has a high peak and a flat trend after the peak. The authors cover the economic importance of persistency and factors that influence it, including physiological, systemic, and local factors, genetics, lambing season, lactation number, number of lambs born, weaning system, milking frequency, udder morphology, stress, and udder health. They conclude with the practical implications of improving persistency.

  • Udder morphology and effects on milk production and ease of milking in dairy sheep - 2004 - Rovai - In this detailed article, the authors review udder and teat anatomy, the heritability of morphological traits, how to evaluate morphology and machine milkability, and the trade-off between production and morphology.

  • Comparison of East Friesian and Lacaune breeds for dairy sheep production in North America - 2004 - Thomas. The authors review a study comparing the East Friesian and Lacaune breeds for breeding, lamb performance and milk production performance.

  • Milk testing, calculation of production, and adjustment factors - 2004 -Berger. Improving milk production by selection of ewes requires high-quality milk production data and techniques to estimate production from individual test days and adjust it for age and other factors. This paper summarises the equipment needed, animal identification, how and when to do the testing, and how to calculate production figures.

  • Collecting and managing data effectively: a case study from the Comisana breed - 2002 - Pinelli. In Sicily, an information system for the Comisana breed has recently been established to help farmers manage their flocks by integrating nucleus flock data with the breeding program to improve milk production. The authors give an overview of the components of the information system.

  • Genetic improvement program for dairy sheep - 2002 - Oltenacu. The principles, requirements, and steps of effective genetic improvement programs at the breed or industry level are summarised in this paper.

  • DNA markers for aseasonality and milk production in sheep - 2002 - Mateescu. Aseasonality refers to sheep whose fertility is less seasonal. Strong seasonality limits the rate of genetic gain. At the time, little was known about genetic markers for aseasonality and production. The authors summarise a study they will run to  identify genes via two methods: finding specific genes associated with aseasonality and production, and whole-genome screening.

  • Choice of breed for dairy sheep production systems - 2001 - Thomas. David Thomas summarises the common breeds in North America before 1992, overseas breeds, the availability of different breeds in North America, evaluates some dairy breeds in present in North America, and discusses the economic effects of breed choice.

  • New developments in the genetic improvement of dairy sheep - 2001 - Arranz. The authors review selection schemes in dairy sheep and their progress, breeding programs in Europe, selection criteria other than milk yield, developments in reproductive techniques, and molecular tools for sheep breeding.

  • Comparison of East Friesian and Lacaune breeding for dairy sheep production systems - 2001 - Thomas. This is a summary of a study comparing East Friesian and Lacaune performance in a Wisconsin setting. There were no large differences in performance, but some small differences in lamb growth and fertility and milk production were found. However, cross breeding of the two breeds may be the best approach because of the hybrid vigour that results.

  • Using light in a dairy sheep operation - 2001 - Kleinpeter. Ken Kleinpeter shares his experimentation with light control to extend their supply of fresh milk across the whole year by increasing the number of out-of-season lambings.

  • Group breeding scheme: a feasible selection program - 2001 - Berger. Yves Berger gives some useful background on the principles of genetic selection for desirable traits and why you might fail due to choosing the wrong traits, too many traits, or having too small a pool of animals to select from. He explains what a group breeding scheme is (a group of producers with a common selection goal where breeding stock is selected and shared among the members of the group).

  • Comparison of East Friesian-crossbred and Lacaune-crossbred ewe lambs for dairy sheep production - first-year results from a multi-year trial - 2000 - Thomas. Due to concerns that East Friesian lambs have inferior health and survival performance compared to other breeds, researchers compared various measures for F1 (cross) East Friesian and Lacaune ewe lambs to the end of their first lactation. In this interim report, the breeds performed similarly for lamb production and udder morphology. East Friesian lambs had longer lactation lengths, higher milk yields, more milk fat and protein, but those differences were not statistically signficant. High-percentage East Friesian ewe lambs mated to East Friesian rams gave birth to more lambs, but the lambs had a higher mortality than lambs from the F1 East Friesian or F1 Lacaune ewes. Levels of East Friesian breeding greater than 50% may result in higher lamb mortality.

  • Udder morphology and machine milking ability in dairy sheep - 2000 - Caja. This detailed paper describes the anatomy and morphology of the dairy sheep udder, explains their importance for machine milkability, and discusses selection for various traits and the upsides and downsides.

  • Reproductive technologies - 2000 - Buckrell. Dr Buckrell details artificial insemination in sheep and the pros and cons of different methods, the use of teaser rams, embryo transfer, disease transfer from AI and ET, and synchronisation protocols.

  • Physiological factors that modify the efficiency of machine milking in dairy ewes - 2000 - McKusick. This paper introduces the concept that machine milking efficiency may be a more useful assessment of an individual ewe than simply milk volume and should be considered in future genetic selection programs. High machine milking efficiency can be defined as getting the maximum amount of milk that is rich in total solids in the shortest amount of time possible with the least amount of physical intervention by the milker, without any negative effects on udder or ewe health. The authors discuss the factors in early lactation (e.g., lamb suckling), between milkings (e.g., udder morphology), and during milking (e.g., manual stripping) that can alter efficiency.

  • Design and implementation of a genetic improvement program for Comisana dairy sheep in Sicily - 2000 - Pinelli. The Comisana breed is the second most important breed in Italy after the Sarda, but, at the time of writing, lacked a systematic genetic improvement program. In this paper, the authors desribe the program that has been developed to improve the Comisana in Siciliy, how the program was progressing, and some expectations for future progress.

  • Farm Adapted Breeds-Crossbreeds. Ghia. 1999 Author discusses concerns with genetics and non-standard record-keeping in industry. Focuses on how milk yield increased at Ewetopia Dairy in Vermont. 

  • Farm Adapted Breeds: A Panel Presentation of Flock Performance Records - Lacaune Dairy Sheep. - 1999 - Regli. Report on predominance of Lacaune sheep in Switzerland and Canada.

  • Preliminary Results: Survival of High Percentage East Friesian Lambs. - 1999 - Thomas/berger/mckusick  Academic research focusing on long term health of high percentage East Friesian lambs.