Objective of the research - to evaluate, using up-to-date statistical–genetic methods, the reproductive characteristics of pig breeds bred in Lithuania, to determine correlation of the characteristics with productivity traits, and to develop an optimised system of pigs genetic evaluation by BLUP method. Tasks of the research was: to determine influence of genetic and non-genetic factors in pigs reproductive characteristics, to evaluate the additive-genetic heritability parameters, and co-response of reproduction traits; to evaluate influence of reproductive characteristics on productivity traits, phenotype and genetic co-response; to develop an optimised pigs genetic evaluation system employing BLUP method, estimating pigs reproductive and productive characteristics, using the integrated multivariate model; to evaluate tendencies of pigs genetic improvement. Novelty of the research: using the method of unifactor and multifactor dispersion analysis, leverage of genetic and non-genetic factors on reproductive characteristics of pigs, breed in Lithuania, was determined; heritability parameters of reproductive characteristics were determined, using modern software; genetic and phenotype co-response of the reproductive characteristics was estimated; genetic correlation between reproductive characteristics and productivity traits was evaluated, using statistical-genetic methods, for the first time in Lithuania; optimised multivariate model for determination of reproductive and... [to full text]

Darbo tikslas : Įvertinti karvių produktyvumo, somatinių ląstelių skaičiaus piene ir reprodukcinių savybių rodiklius ir nustatyti jų tarpusavio ryšius. Darbo uždaviniai: 1. Įvertinti: a) Karvių pieno kiekio ir sudėties (riebumo, baltymingumo) rodiklius; b) Somatinių ląstelių skaičių karvių piene; c) Karvių reprodukcines savybes. 2. Nustatyti karvių pieno kiekio bei sudėties, somatinių ląstelių skaičiaus ir reprodukcinių savybių tarpusavio ryšius. 3. Apskaičiuoti koreliacijos koeficientus tarp karvių pieno kiekio bei sudėties, somatinių ląstelių skaičiaus ir reprodukcinių savybių rodiklių. Išvados: 1. Įvertinus karvių pieno kiekio ir sudėties rodiklius nustatyta, kad iš visų tirtų karvių vidutiniškai primelžta 5176,442 kg pieno, gauta 223,08 kg riebalų ir 175,07 kg baltymų. Geresniu produktyvumu išsiskyrė karvės, kurios buvo laikomos B ūkyje. Iš šių karvių vidutiniškai daugiau buvo primelžta 912,99 kg pieno, gauta 29,30 kg riebalų ir 31,74 kg baltymų nei A ūkyje laikomų karvių. 2. Įvertinus SLS karvių piene nustatyta, kad tirtų karvių piene vidutinis SLS buvo 307,946 tūkst./cm3. Tai atitinka tinkamo supirkimo pienui keliamus ES reikalavimus. Tirtų karvių, laikomų A ūkyje SLS piene buvo 15,05 tūkst./cm3 mažesnis. 3. Įvertinus tirtų karvių reprodukcines savybes nustatyta, kad karvės buvo vidutiniškai 3,5 laktacijų skaičiaus, laktacija vidutiniškai truko 225,6 dienas, neveršingumo laikotarpis – 155,6 dienas, trukmė tarp apsiveršiavimų – 470,4 dienos ir vidutinis sėklinimų... [toliau žr. visą tekstą] / Aim of work: To evaluate cow productivity, somatic cell count in milk and reproduction traits and to determine correlation between them. Place of research: The work was carried out in the Department of Animal Breeding and Genetics of Veterinary Academy and also in the dairy cow‘s farm during 2011 – 2013 years of studies. The Results of Survey: Evaluation of cow milk amount and composition showed that average amount of milk from all analyzed cows was 5183.442 kg, 223.08 kg of fat was obtained, as well as 175.07 kg of proteins. Cows in farm B were more productive. 912.99 kg more milk, 29.30 kg more fat and 31.74 kg proteins were obtained from these cows on an average, in comparison to cows in farm A. Evaluation of SCC in cow milk showed that average SCC( somatic cells count) in analyzed cow milk was 307.946 thousand/cm3. It corresponds to EU requirements established for milk for production. SCC in milk of analyzed cows in farm A was 15.05 thousand/cm3 less. Evaluation of reproduction traits of analyzed cows showed that lactation of cows occurred 3.5 times on an average, average duration of lactation was 225.6 days, dry period lasted 155.6 days, number of days between parturitions was 470.4 and average number of seminations was 1.9. The research allowed to determine statistically reliable negative phenotypic correlation between SCC in milk and amount of milk (p<0.05). As productivity of cows increased, SCC in milk increased as well, it caused more frequent udder inflammation to... [to full text]

Darbo tikslas: Įvertinti genetinių veiksnių įtaką karvių produktyvumo, melžimo ir reprodukcinių savybių rodikliams pieninių galvijų ūkyje. Tyrimo rezultatai: Iš viso buvo ištirtos 475 karvės, iš kurių iš kurių 29 Airšyrų, 12 Anglerų, 89 Holšteinų, 71 Lietuvos juodmargių, 240 Lietuvos žalujų, 19 Vokietijos juodmargių, 15 Žalmargių holšteinų veilės karvės. Tyrimo metu buvo nagrinėta karvių produktyvumo, karvių melžimo ir reprodukcinės savybės. Įvertinus tirtų karvių produktyvumą nustatyta, kad vidutinis tirtų karvių pieno kiekis per laktaciją 4974,78 kg, pieno riebumas - 4,69 proc., pieno baltymingumas – 3,53 proc., somatinių ląstelių skaičius piene – 567,52 tūkst./ml. Vidutinis melžimo greitis 1,80 kg/min., vidutinė melžimo trukmė – 4,98 min. Tirtos karvės sėklintos vidutiniškai 2,36 karto, neveršingumo periodas truko 150,19 dienų, vidutinė veršingumo trukmė 283,33 dienos, vidutinis pirmo sėklinimo amžius - 25,61 mėn. Įvertinus karvių veislės įtaką tirtiems rodikliams, didžiausias produktyvumas nustatytas Anglerų veislės karvių (5772,67 kg, P>0,05), mažiausias SLS buvo Žalmargių holšteinų veislės karvių piene (209,29 SLS tūkst./ml, P<0,005). Geriausios melžimo savybės buvo Holšteinų veislės karvių (melžimo greitis 1,98 kg/min., P>0,05, trukmė 4,85 min., P>0,05). Geriausiomis reprodukcinėmis savybėmis išsiskyrė Žalmargių holšteinų veislės karvės (sėklinta 1,15 kartų, P<0,001 neveršingumo periodas 83,67 d. P<0,001). Įvertinus skirtingų bulių dukterų įtaką tirtiems rodikliams... [toliau žr. visą tekstą] / The aim of the work: To evaluate the influence of genetic factors on productivity, milkability and reproduction traits of dairy cattle. The Results of Survey: The analysis was based on 475 dairy cows from different breeds, in which 29 Ayrshire, 12 Angler, 89 Holstein, 71 Lithuanian Black and White, 240 Lithuanian Red, 19 Germany Black and White, 15 White Holstein. During the study, some data have been analysed influence of the genetic factors on cows’ productivity, milkability and reproduction traits. The evaluation of the productivity of cows showed that the average amount of milk cows during lactation 4974.78 kg, of milk fat - 4.69 percent milk protein - 3.53 percent. Somatic cell count in milk - 567.52 thousand/ml. The average of milking speed of 1.80 kg/min., the average of milking time - 4.98 min. Cows inseminated an average of 2.36 times, servis period lasted 150.19 days, the average of gestation period 283.33 days, the average age at the first insemination - 25.61 months. The statistical analysis of genetic factors showed, that the highest productivity was of Angler cows (5772.67 kg, P>0.05). The lowest SCC was in White Holstein cows’ milk (209.29 thousand/ml, P<0.005). The best milkability traits were of Holstein cows (milkikin speed 1.98 kg/min., P>0.05; time 4.85 min., P>0.05). The best reproduction traits was estimated of White Holstein cows (insemination 1.15 times, P<0.001, servis period 83.67 d. P<0.001). The evaluation of different bulls daughters studied... [to full text]

Records of the La Rochelle S.A. Mutton Merino stud were analysed to determine the importance of possible contributing non-genetic sources of variation on growth and reproductive traits. Growth traits analysed were pre-weaning weight (42dW), weaning weight (100dW), 205d weight, ADG's and Kleiber Ratio's (KR) for both 42d and 100d. All the included effects, i.e. year, sex, birth status, season, age of dam and the year x sire interaction, were highly significant (P<0.001) for the growth traits. Reproduction traits measured were mean number of lambs born per ewe per year, mean Kg lamb weaned per ewe per year, percentage twins and fecundity. Year was the only significant effect (P<0.001) for all four reproduction traits. Data of records between 1974 and 1995 were used to estimate additive direct and additive maternal heritabilities for seven growth traits. The estimates of the direct heritabilities varied between 0.166 for 42dW and 0.513 for 205dW. The estimates of the maternal heritabilities were within the 0.042 (42dW) to 0.370 (100dADG) range. Estimates of the covariance between the direct additive and maternal additive components were generally negative and of a substantial size (-0.215 to -0.674). Additive direct and additive maternal heritabilities for four reproductive traits were also estimated. The estimates for direct additive heritabilities varied between 0.039 for fecundity and 0.177 for Kg lamb weaned per ewe per year. Estimates for the maternal additive heritabilities were correspondingly low, varying from 0.007 for lambs born per ewe per year to 0.197 for percentage twins. Estimates of covariance between the additive direct and additive maternal components were negative. Genetic trends of the flock were studied. The main objective of the breeder was to improve the reproductive efficiency of the flock, whilst decreasing the incidence of very large lambs. Selection pressure on reproductive performance hasn't yet attained the desired effect as three of the four reproductive traits measured, showed very little or no improvement. Lambs do however have lower body weights, while the 100dADG and 100dKR have improved. / Dissertation (MSc(Agric))--University of Pretoria, 2004. / Animal and Wildlife Sciences / unrestricted