Influence of birth type on body weight of lambs from birth to weaning in various strains of sheep Pramenka

The dynamics of increasing of bodyweight of lambs is conditioned by genetic factors, environmental factors and their interaction. The aim of this work was study variability of bodyweight of lambs related to type of birth of lambs in sheep genotype of four different strains of pramenka type and four growth stage: at the birth time, at the 30, 60 and 90 days of age after birth. For this investigation used lambs of four strains (Svrljiški, Pirotski, Sjeniĉki, Šarplaninski) of sheep type Pramenka (450 lambs per strain) for study dinamics of bodyweight at the time of birth, 30, 60 and 90 days after birth during three years of experiment (2011-2013). The results showed that the bodyweight of lambs born singles was higher than bodyweight of lambs born twins in studied four sheep genotypes i.e. Pirotski (4.00 kg : 3.40 kg), Svrljiški (3.90 kg : 3.79 kg), Sjeniĉki (3.73 kg : 3.61 kg), Šarplaninski (3.81 kg : 3.74 kg). The differences of bodyweight between lambs born singles and twins was significant for genotypes Pirot pramenka and Svrljig pramenka, on the level of significance for Sjenica pramenka and was not significant in Šarplanina pramenka. At the age of 30 days, the influence of birth type on the bodyweight of lambs was not statistically significant in any of the examined strains. The difference of bodyweight between singles and twins was statistically significant at the 60 days old of lambs in Svrljig pramenka and in lambs at 90 days old of Svrljig pramenka. On the base of results is established that type of born associated with significant differences of bodyweight at the birht time expressed later at the 60 and 90 day old lambs

SOME ASPECTS OF INBREEDING AND ITS EFFECT ON GROWTH TRAITS OF LAMBS –A REVIEW

Inbreeding seems to be a useful tool to improve the population by increasing the frequency of desirable genes, but the first result of inbreeding is inbreeding depression. Inbreeding depression implies the reduction of additive genetic variance and phenotypic values for efficiency traits in inbred animals. The kinship degree is measured by the inbreeding coefficient and expressed in percentage (%) from 0 to 100, that as the percentage higher, the higher the kinship. Nevertheless, one thing is for sure, practice in sheep breeding has shown that the use of inbreeding causes undesirable consequences like reduction of body shape or abnormal development, developmental delay, resistance to external influences and diseases, poor fertility or infertility, metabolic disorders, negative characteristics in fattening, albinism and the appearance of degenerative traits, loss of instinct, psychophysical defects and so on. Inbreeding is an inevitable companion of livestock production. No matter how hard we try to avoid it, in practice, it is almost impossible. It could not completely eliminate, but with proper breeding and selection management, it can be kept under control

BIODIVERSITY, SEASONAL DYNAMICS AND GEOGRAPHICAL DISTRIBUTION OF SHEEP AND GOAT TICKS IN SERBIA

The paper examines the results of the research on the tiny fauna of tiny ruminants in the territory of the Republic of Serbia, made in the period 1989-2019. The research covered all the regions from Vojvodina to Kosovo and included long term-tropical biodiversity studies, full dimorphism and seasonal dynamics of occurence. During our study we established presence of Ixodes ricimus, I. persucatus, Rhipicephalus sanguineus, R. bursa, R. (Boophilus) annulatus, Boophilus calcaratus, Dermacentor marginatus, D. recticulatus, Haemophysalis punctata, Ha. inermis Ha. Sulcata, Hyalomma savignyi, Hy. Marginatum marginatum and Hy.detritium. The sex ratio of ixodid species was in favor of females and was 61.02%: 38.98%. More males than females ( 65.08%: 34.92%) were observed only in the species Rhipicephalus bursa. For the most commonly found species of Rhipicephalus sanguineus and Ixodes castor, this ratio was 69.50%: 30.50 and 63.42%: 36.58%, in favor of females

COCCIDIOSIS IN LAMBS IN NORTHERN SERBIA (VOJVODINA)

The paper examines the results of the research on the coccidiosis in lambs in Vojvodiina. The present study was conducted in 90 sheep flocks from the all territory of Vojvodina in the period from March 2014 to January 2015. Sheep of both sexes (320 males and 580 females, for a total of 900) were randomly chosen. There were 610 adults (one-year-old and above) and 290 lambs. Colected faeces samples were examined using routine coprological methods. During our examination coccidiosis were found at 32.22% (29/90) flocks. We usally occured mixed infection with 2-3 coccidia species. At sheep most abundant species were E.ovinoidalis found at 87.1%, followed by E faurei (42%), Eimeria ahsata (37%), E. granulosa (31%), E. intricata (19%), and E. pallida (8%). Oocyst were found at adult ant young animals, but clinical sign of disease were present only at young animals. The number of excreted oocysts was higher in lambs than in adult sheep

GENETIC STRATEGY OF HOMOZYGOUS AND HETEROZYGOUS BALANCE IN SHEEP POPULATIONS

The main farmers goal is breeding of pure sheep breed outside the kinship. That way they want to preserve and improve qualities of the breed, such as high production of meat, milk or wool, strong construction, high fertility, length of productive life, health, etc. It is a challenge for breeders because it represents a management planning balance between homozygosity and heterozygosity. Breeding sheep in a purebred requires a certain level of genetically predictable homozygosity to promote desirable traits. Balancing is appropriate to avoid inbreeding depression. A particular problem arises in small populations, which have only hope in the line breeding system. This review paper discusses iptions to overcome this situation

PHENOTYPIC AND MOLECULAR PREDICTION AND SELECTION OF DOMESTIC ANIMALS

Environmental factors are always present, it is difficult to reliably determine the value of an animal's genotype. The fact that genotypes are not passed from generation to generation, but numerous genes that exhibit average effects in relation to the mean value of the population also complicated genotype assessment. In order to estimate the genotype of an individual as accurately as possible, we must apply a series of procedures that collectively at the end of the journey can give us a clearer picture of what we are looking for. The basis of selection work is the assessment of the breeding value of domestic animals on the basis of which the selection of individuals or groups for further reproduction and use in production. With the development of computer technology, statistical software was obtained, which enabled faster and more reliable data processing and assessment of breeding value, using linear models. From the first ideas of DNA molecule analysis for that purpose until today, many procedures have been applied and improved and many genetic markers and methods have been discovered, so that in practical terms it is necessary to accept a common platform called genomic selection. Genomic selection - is a powerful tool for future use. Currently, the efficiency of genomic selection is limited by various interactions between the locus of quantitative traits, the variability of quantitative traits, and the influence of environmental factors. However, research results in many countries have confirmed that the use of standard statistical methods together with genomic selection increases reliability in predicting the breeding values of animals