Važniji faktori koji utiču na plodnost kod ovaca

Efficiency of sheep production is conditioned by fertility. According to some authors number of offspring obtained per lambing is more important than gain of weight. Genetic relationships involving reproductive traits were seldom studied. Reproductive traits have low heritabilities, a discrete phenotypic expression, and are expressed only in sexually mature ewes leading to low selection intensities and long generation intervals. Documentation of realized selection response is also often complicated by the low heritabilities of fertility traits. Existence of a major gene affecting prolificacy had been suggested and at that time there were many sceptics who strongly doubted that a trait as complex as reproduction could be profoundly influenced by a single gene. Major genes affecting prolificacy in sheep was founded. A mutation in the bone morphogenetic protein 15 gene (BMP15, also known as GDF9B) responsible for high prolificacy in Inverdale sheep had been discovered and evidence of segregating major genes was being reported from flocks around the world. Development of gene mapping techniques, and locating alleles that are responsible for the fertility of sheep began a new chapter in predicting and controlling the fertility of sheep. The beneficial effects of nutrition on reproduction in sheep are well known. This procedure is known as flushing. The effect of Body Condition Score (BCS), before mating, during mating and after mating period, on reproductive efficiency of different breeds of sheep in the different rearing systems were studied. The farm manager has the ability to control or at least to manipulate the factors that have an impact on fertility.Efikasnost proizvodnje ovaca je uslovljena plodnošću. Prema nekim autorima broja potomaka dobijenih po jagnjenju je važnije od prirasta i mase tela. Genetski uticaji koji uključuju reproduktivne osobine se retko izučavaju. Plodnost ovaca ima nizak heritabilitiet, diskretnu fenotipsku ekspresiju, a izražena je samo u seksualno zrelih ovaca, što dovodi do niskog intenziteta selekcije i dugih generacijskih intervala. Otkriće major gena koji utiču na plodnost je u to vreme otkrilo mnogo skeptika koji su snažno sumnjali da takav kompleks reprodukcije može biti duboko pod uticajem jednog gena. Glavne geni utiču na plodnost kod ovaca i ovnova. Mutacija u koštanoj morfogenetsko proteina 15 gena (BMP15, takođe poznatom kao GDF9B) otkrivena je kod mnogih ovaca širom sveta, kao dokaz segregacije major gena. Razvojem tehnika mapiranja gena i lociranja alela koji su odgovorni za plodnost ovaca, počelo je novo poglavlje u predviđanju i kontrolisanju plodnosti ovaca. Povoljni efekti ishrane na reprodukciju u ovaca su dobro poznati. Ovaj postupak je poznat kao flushing, pred oplodnju. Uticaj kondicije tela (BCS), pred parenje, tokom parenja i posle parenja na reproduktivnu efikasnost različitih rasa ovaca u različitim podizanju sistema su takođe proučavali mnogi ovde pomenuti autori. Farmer putem menadžmenta ima mogućnost da kontroliše, ili bar da manipuliše faktorima koji imaju uticaj na plodnostovaca, a što je takođe predstavljeno u ovom preglednom radu

Linearna povezanost osobina porasta jagnjadi šarplaninske rase u ekstenzivnim uslovima gajenja

The fastest phase of growth, observed in young animals, is often assumed to be linear, and linear regressions or ratios between BW gain and time are used to model growth. However, growth curves, due to their flexibility, are likely to be more suitable to describe even early growth. The research was performed in the region of Sharplanina Mountain in the population of the local Šarplanina breed of sheep. The following traits of lambs were considered: BWB, BW30, BW60 and BW90. Statistical analysis was conducted using the Pearson's correlation and multivariate linear regression model. This involved computing all possible and the best subset regression equation. Each equation was then assessed by its coefficient of determination (R2) and the constant based on the number of variable that used for the prediction. Results showed that weight of lambs from birth to weaning increased by about six times. Specifically lambs achieved an average total gain of 17.66 kg, or 196 g per day. There were a very significant correlation (P (lt) 0.01) between BWB and BW30, BW60 and BW90. Likewise, shown a very significant correlation (P (lt) 0.01) between BW30-BW60, BW30- BW90 and BW60-BW90. Also shown the coefficient of multiple determinations (R-squared R2) was 0.507 which means that 50.7% of the variance BW90, determined variance of the predictor variables represented in the model. Adjusted coefficient of multiple determination (adjusted R2) is 0.506 which means that 50.6% of the variance BW90, determined variance of the predictor variables that are in the model. Any increase in weight of lambs during the observed period of age is associated with an increase of dependent variable BW90. In particular, any increase in BW30 to 1 kg, is associated with an increase in BW90 to 1.928 kg.Istraživanje je sprovedeno u regionu Šar planine u populaciji lokalne šarplaninske rase ovaca. Sledeće osobine jagnjad su posmatrane: masa pri rođenju, sa 30,60 i 90 dana uzrasta (BWB, BW30, BW60 i BW90). Statistička analiza je sprovedena primenom SPSS paketa. Izračunate su Pearson korelacije i multivarijantna linearna regresija. To je značilo računanje svih mogućih i najboljih podskupova jednačina regresije. Svaka jednačina je ocenjena kao i njen koeficijent determinacije (R2). Rezultati su pokazali da je masa jagnjadi od rođenja do odbijanja povećana za oko šest puta. Konkretno jagnjad su ostvarila prosečan ukupan prirast od 17,66 kg, ili 196 g dnevno. Utvrđena je vrlo značajna korelacija (P (lt) 0,01) između BWB i BW30, BW60 i BW90. Isto tako, pokazala se veoma značajna korelacija (P (lt) 0,01) između BW30-BW60, BW30-BW90 i BW60-BW90. Takođe, dobijeni koeficijent višestruke determinacije (R-skuared R2) znači da je 50,7% varijanse BW90, determinisano varijansom prediktorskih varijabli predstavljenih u modelu. Korigovani koeficijent višestruke determinacije (R2 prilagođeni) je 0.506, što znači da je 50,6% varijanse BW90, uslovljeno varijansama prediktorskih varijabli koje su u modelu. Svako povećanje mase jagnjadi u toku posmatranog perioda života je povezano sa povećanjem zavisno promenljive BW90. Praktično, svako povećanje BW30 za 1 kg, je povezano sa povećanjem BW90 za 1.928 kg

Uticaj genetskih i faktora životne sredine na fenotipske karakteristike jagnjadi

The aim of this study was to determine the influence of environmental factors affecting body weight variability of lambs in two crossbreed groups: Pirot x Württemberg and Sjenica x Württemberg. Both populations were managed under the same farm conditions. The data were analyzed to determine the effect of age of the dam, weight of dam, birth type, sex, year and season, on the birth weight and weaning weight of crossbreed lambs. Statistical analysis was performed by GLM procedure using the SPSS statistical package program. The average birth weight of Pirot x Württemberg lambs was 3.56 kg while Sjenica x Württemberg lambs was slightly higher at 3.69 kg. The difference on birth weight between the two crosses was not statistically significant (P>0.05). The average weaning weight of Pirot x Württemberg lambs was 23.54 kg while Sjenica x Württemberg lambs had higher weight at 24.37 kg. The difference of 0.83 kg on weaning weight was statistically significant (P (lt) 0.05). Body weight, depending on the environmental factors, ranged from 3.17 to 3.96 kg at birth and from 22.12 to 24.18 kg at weaning in Pirot x Württemberg lambs. Body weight of Sjenica x Württemberg lambs ranged from 3.39 to 3.99 kg at birth and from 22.69 to 25.44 kg at weaning. Statistical analysis showed that the differences were statistically significant (P (lt) 0.05) and highly significant (P (lt) 0.01).Cilj ovog istraživanja je bio da se utvrdi uticaj faktora životne sredine na varijabilnost telesne težine jagnjadi u dve grupe meleza: pirotska x virtemberg I sjenička x virtemberg. Obe populacije su držane pod istim uslovima na farmi. Podaci su analizirani da se utvrdi uticaj starosti majke, njene težine, tipa rođenja, pola, godine i sezone, na težinu na rođenju i odbijanju jagnjadi meleza. Statistička analiza je izvedena pomoću GLM procedure, koristeći SPSS statistički program paket. Prosečna telesna masa meleza pirotska x virtemberg je 3,56 kg, dok sjenička x virtemberg jagnjad bila nešto veća - 3,69 kg. Razlika u težini na rođenju između dve grupe meleza nije bila statistički značajna (P>0,05). Prosečna težina na odbijanju jagnjadi meleza pirotska x virtemberg je bila 23,54 kg, dok su jagnjad melezi sjenička x virtemberg imala veću težinu - 24,37 kg. Razlika težine na zalučenju od 0,83 kg je statistički značajna (P (lt) 0,05). Telesna masa, u zavisnosti od faktora sredine, kretala se u rasponu od 3,17 do 3,96 kg na rođenju i od 22,12 do 24,18 kg na odbijanju u jagnjadi pirotska x virtemberg. Telesna masa jagnjadi sjenička x virtemberg kretala se u rasponu od 3,39 do 3,99 kg na rođenju i od 22,69 do 25,44 kg na odbijanju. Statistička analiza pokazala je da su razlike statistički značajne (P (lt) 0,05) i visoko značajne (P (lt) 0,01)

Povezanost između mase tela pri rođenju i karakteristika porasta jagnjadi

Research was carried out in population of R2 generation Pirot pramenka x Pirot improved sheep during period of three years. Lambs were divided into three groups: I from 2.5 kg to 3.5 kg; II from 3.6 kg to 4.5 kg; III from 4.6 kg to 5.5 kg. Weight of lambs was controlled at birth, with 30, 60 and 90 days of age. Average body weight at birth of the tested lambs was 3.35 kg in the first group, 4.30 kg in the second group and 5.06 kg in the third group. At 30 days of age, the body weight of the lambs was 10.19 kg in the first group, 11.39 kg in the second and 12.49 kg in the third group. All these differences in body weight of lambs at birth were statistically highly significant (P¬ 0.01). With 60 days of age, average body weight was 16.48 kg in the first group, 19.01 kg in the second and 20.49 kg in the third group. Differences between groups of lambs at this age were statistically very significant (P¬0.01).On the end of experiment at 90 days of lambs age, we have found the following values of the body weight of lambs: 26.35 kg in the first group, when the second 30.49 kg and 28.93 kg in the third group. Differences between groups of lambs at this age were statistically very significant (P¬0.01). At the age of 90 days maximum weight of the body was in the second group of lambs, or a group which body weight at birth occupied the mean of the population. Correlations between body weights of lambs vary from weak to midsized values. The highest values of correlation coefficients were found between body weight at birth and weight of lambs at 30 days of age.Istraživanja su sprovedena u populaciji R2 generacije Pirotska pramenka x Pirotska oplemenjena ovca tokom perioda od tri godine. Jagnjad su bila podeljeni u tri grupe: I od 2,5 kg do 3,5 kg; II od 3,6 kg do 4,5 kg; III od 4,6 kg do 5,5 kg. Masa jagnjadi je kontrolisana na rođenju, sa 30, 60 i 90 dana starosti. Prosečna telesna težina na rođenju testiranih jagnjadi bila je 3,35 kg u prvoj grupi, 4,30 kg u drugoj grupi i 5,06 kg u trećoj grupi . Sa 30 dana starosti ,telesna masa jagnjadi bila je 10,19 kg u prvoj grupi, 11,39 kg udrugoj i 12,49 kg u trećoj grupi. Sve ove razlike u telesnoj masi jagnjadi na rođenju su visoko statistički značajne (P¬0,01). Sa 60 dana starosti, prosečna telesna masa je bila 16,48 kg u prvoj grupi, 19,01 kg udrugoj i 20,49 kg u trećoj grupi. Razlike između grupa jagnjadi u ovom uzrastu su statistički vrlo značajne (P¬0,01). Na kraju eksperimenta sa 90 dana starosti, pronašli smo sledeće vrednosti telesne mase jagnjadi: 26.35 kg u prvoj grupi, 30,49 kg u drugoj grupi i 28,93 kg u trećoj grupi. Razlike između grupa jagnjadi u ovom uzrastu su statistički vrlo značajne (P¬0,01). U uzrastu od 90 dana maksimalna masa tela je registrovana u drugoj grupi jagnjadi, ili grupi čija telesna masa na rođenju zauzima srednju vrednost populacije. Korelacija između telesne mase jagnjadi variraju od slabe do srednje vrednosti. Najveće vrednosti koeficijenata korelacije su pronađene između telesne mase na rođenju i mase jagnjadi sa 30 dana starosti

Ispitivanje antioksidantnog potencijala herbe čestoslavice (Veronica officinalis L., Scrophulariaceae)

IV Kongres farmaceuta Srbije sa međunarodnim učešćem, 29. novembar – 2. decembar 2006 godine, Beogra