Texas AgriLife Research

Genetic Selection Tools and Techniques to Benefit Texas Range Sheep Producers


The nationís leading sheep state in terms of numbers, Texas, has historically utilized phenotypic appraisal and

information from centralized performance tests as the primary selection tools within their flocks. However, with no

advancement in reproductive rate and lamb crop percentage over the last several decades Rambouillet breeders in

particular have struggled to maintain profitable production, as evident by declining numbers of wool sheep and wool

sheep producers. Hair sheep production has grown exponentially in Texas over the last 20 years. Dorper is the

primary breed of hair or shedding sheep that have replaced wool sheep, along with meat goat herds. For the most

part, Dorper breeders have not used NSIP to better select animals for productivity and animal health. Regionally

within the United States, certain producers and producer groups have been successful utilizing the genetic tracking

program through the National Sheep Improvement Program to increase lamb crop, parasite resistance, and value of

their annual wool clip. Limited by the large scale of most range operations, extensive production systems, and a lack

of emphasis from state industry leaders, NSIP is underutilized by Texas seedstock sheep producers. Most seedstock

producers use multi‐sire pasture mating and range lamb, presenting difficulties for pedigree determination, and in

turn, collection of genetic information. Texas falls behind the rest of the nation in terms of average lamb crop,

number of lambs born, and number of lambs weaned. With the low heritability of reproductive traits, it is very

challenging to make much progress from limited data collection. NSIP excels at offering valuable information in these

regards due to the extensive tracking and linkage of animals within a flock. This concept has been validated in

Australia and New Zealand, where this technology is widely utilized and sheep production efficiency has never been

higher. Within America, the cattle seedstock industry has made significant gains with the adoption of EPDs, which

again are similar to the information provided by NSIP.