Dairy Sheep Symposium - the Department of Animal Sciences ...

In the case of cheese the problem is different and individual traceability is not possible.
However there are many projects devoted to the assignment of a product to a specific breed. This
aspect could be very useful for products with appellation of origin and for this purpose a
combination of microsatellite markers can be used (Arranz et al., 2001). Moreover breed-specific
markers such as mitochondrial haplotypes or a combination of breed-specific SNPs are being
evaluated for this goal. For this purpose more powerful statistical tools should be developed
mainly in Bayesian or Artificial Intelligence frameworks.
Final remark
As a general conclusion from the present paper we may indicate that most dairy sheep
breeding programs which are currently being undertaken are based on milk yield criteria, and no
or little advantage is taken from other tools which could improve breeding programs efficiency.
Certain strategies described here are already available for their practical utilization. This is the
case, for example, of recent innovations in reproductive techniques. For their part, among the
selection parameters we can point out milk composition traits, udder morphology and somatic
cell count (SCC), which are already considered among the selection criteria in a few sheep
breeds, situation that most probably will be made extensive to the rest of breeds. Genetic
resistance to pathological processes is probably one the most promising areas of investigation.
Until now it has led to important findings only in a few cases, among which we can cite
“scrapie”, allowing for a selection of favorable genotypes. Other aspects approached in this
paper, such as molecular tools, need to be deeply explored before they can be used in practice,
but presumably further investigations will make their application possible in a near future.
Finally we should remark that besides the economic benefit, all these advancements will
facilitate management procedures and this will undoubtedly result in an amelioration of sheep
farmers livelihood.
Literature cited
Arranz, J.J., Bayón, Y., San Primitivo, F. (2001). Differentiation among Spanish sheep breeds
using microsatellites. Genet. Sel. Evol. (in press).
Astruc, J.M., Barillet, F. (2000). Report of the working group on milk recording of sheep. 32nd
Biennial Session of ICAR and INTERBULL. Bled, Slovenia, between 14-19 May 2000.
Banos, G., Shook, G.E. (1990). Genotype by environment interaction and genetic correlations among
parities for somatic cell count and milk yield. J. Dairy Sci., 73: 2563-2573.
Barillet, F. (1997). “Genetics of milk production”. Piper, L.; Ruvinsky, A. The genetics of the
sheep. 539-567. Oxford, CAB International.
Barillet, F., Marie, C., Jacquin, M., Lagriffoul, G., Astruc, J.M. (2001). The French Lacaune
dairy sheep breed: use in France and abroad in the last 40 years. Lives. Prod. Sci., 71: 17-29.
Beattie, C.W. (1994). Livestock genome maps. Trends Genet., 10: 334-338.
Brenneman, R.A., Davis, S.K., Sanders, J.O., Burns, B.M., Wheeler, T.C., Turner, J.W., Taylor,
J.F. (1996). The polled locus maps to BTA1 in a Bos indicus x Bos taurus cross. J. Hered. 87,
156–161.
Bryne, P.F., McMullen, M.D. (1996). Defining genes for agricultural traits: QTL analysis and the
candidate gene approach. Probe 7: 24-27.
CERSYRA, 2001. Memoria de actividades del ESROM 2000. 35 pp. Valdepeñas. Spain