Der vorliegende Tierzuchtreport schreibt in bewährter Weise die Ergebnisse aus der Tierzucht fort und liefert damit wertvolles Zahlenmaterial für unterschiedlichste Zwecke. Angaben zu Organisation und Struktur der sächsischen Tierzucht sowie ein Adressenverzeichnis runden die Informationen ab. Die mit dem Inkrafttreten des novellierten Tierzuchtgesetzes im Dezember 2006 eingeleiteten Veränderungsprozesse im Tierzuchtrecht gilt es weiter zu begleiten und im Freistaat umzusetzen. Schon jetzt gilt es, die Situation nach Auslauf der Übergangsregelungen zum 31.12.2013 im Auge zu haben und diesen Prozess, der weit reichende Konsequenzen für die organisierte Tierzucht mit sich bringt, seitens der Tierzuchtverwaltung aktiv zu gestalten.

Der vorliegende Tierzuchtreport 2009 schreibt in bewährter Weise die Ergebnisse aus der sächsischen Tierzucht für das Jahr 2008 fort. Neben den Angaben zu Rassen, Zuchtbeständen und Ergebnissen der Leistungsprüfungen werden eine Reihe weiterer Angaben zur Tierhaltung aller Nutztierarten in Sachsen dargestellt. Angaben zu Organisation und Struktur der sächsischen Tierzucht sowie ein Adressenverzeichnis runden die Informationen ab.

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Performance and progeny tests were carried out between 1975-1977 to obtain estimates of genetic variation in the growth rate of artificially reared Suffolk ram lambs both between and within flocks. It was found that there was individual variation in rams' breeding value and moderate heritability estimates of growth rate were obtained. Two further experiments were designed to investigate a problem arising from the performance test of 1975, when 24% of the sires failed to mate with ewes when they were introduced to them for the first time. The objectives of the first experiment were to investigate the effects of method of rearing and female company on the attainment of puberty. The second experiment was designed with the additional objectives of investigating whether early weaning of naturally reared ram lambs could provide an alternative to artificial rearing from birth. The effects of repeated pen libido and semen tests on sexual performance and semen traits were also investigated. The results obtained indicated that lambs which were either artificially reared, or naturally reared, but early-weaned at two months of age, attained puberty at an earlier age than those reared naturally with their dams to six months of age. It was also found that repeated libido testing significantly improved sexual performance in terms of number of mounts and number of ejaculations achieved within the 20-minute test period.

Two sheep group breeding schemes were considered in this study to examine the genetic progress made over a 20 year period and the success of running such schemes in practice. The data were records of lamb weaning weight in the CAMDA scheme (Welsh Mountain breed) and the Lleyn scheme (Lleyn breed), collected between 1976 and 1996. After the edits, a total of 31,161 records for the CAMDA and 29,090 records for the Lleyn scheme were available for the analyses. The estimates of the heritability of weaning weight for individual flocks were low to moderate. In the CAMDA scheme, the estimates of the direct and maternal heritability values ranged from 0.04 to 0.43, and 0.03 to 0.11, respectively. The ratio of temporary environmental variance over the total variance ranged between 0.13 to 0.35. The estimates of total heritability values in flocks of 12 and 18 weeks of age were in the range of 0.23-0.45 and 0.07-0.18, respectively. In the Lleyn scheme, the estimates of the ratio of temporary environmental variance over the total variance, and the direct and maternal heritability values ranged from 0.15 to 0.39, 0.03 to 0.31, and 0.04 and 0.23, respectively. The estimates of the total heritability values in individual flocks of the scheme ranged from 0.07 to 0.33. The differences in heritability values between the flocks, reflected the differences in the model of analysis fitted, and size and structure of the data available for individual flocks of the scheme. It is concluded that group breeding schemes are a viable means of improving the production of traits of a breed, but that more attention should be paid in the setting up of the schemes, to a scoring system which will accurately reflect the market value of the stock. The application of group breeding schemes in Iran would require taking account of the differences in the social and climatic environments. Much greater attention would be needed to determine the selection objectives and these would need to be properly included in the selection index.

The phenomenon of seasonability of reproduction restricts the ewe to only one lambing around the same time every year, which in turn prevents an even supply of lamb meat to the market. The long term objective of the current study was to develop two systems of early and summer lambing using alternative techniques for the manipulation of sheep production in an attempt to produce high quality lamb throughout the year. In recent years, major advances in our knowledge of seasonality of reproduction have been the recognition of the integral role of the pineal gland and its indoleamine melatonin in the timing of reproductive activity and the use of the pattern of reproductive behaviour in sheep in the manipulation of reproductive processes. Therefore, the current study aimed at examining the use of melatonin and/or the 'ram effect' in early and summer lambing systems in order to report on their effectiveness in advancing the breeding season and/or enhancing fecundity. Also, the concern over the seasonal variation in libido and semen quality in the ram made it necessary to examine ways of eliminating the seasonal depression in the mating performance and capcity of the ram. Experiments 1, 2 and 3 examined the effectiveness of the intraruminal device of melatonin administration and/or the 'ram effect' in advancing the breeding season of the ewes. Also the effects of duration and methods of 'teasing' were assessed.