The aim of this study was to obtain unbiased estimates of the diversity parameters, the population history, and the degree of admixture in Cika cattle which represents the local admixed breeds at ...risk of extinction undergoing challenging conservation programs. Genetic analyses were performed on the genome-wide Single Nucleotide Polymorphism (SNP) Illumina Bovine SNP50 array data of 76 Cika animals and 531 animals from 14 reference populations. To obtain unbiased estimates we used short haplotypes spanning four markers instead of single SNPs to avoid an ascertainment bias of the BovineSNP50 array. Genome-wide haplotypes combined with partial pedigree and type trait classification show the potential to improve identification of purebred animals with a low degree of admixture. Phylogenetic analyses demonstrated unique genetic identity of Cika animals. Genetic distance matrix presented by rooted Neighbour-Net suggested long and broad phylogenetic connection between Cika and Pinzgauer. Unsupervised clustering performed by the admixture analysis and two-dimensional presentation of the genetic distances between individuals also suggest Cika is a distinct breed despite being similar in appearance to Pinzgauer. Animals identified as the most purebred could be used as a nucleus for a recovery of the native genetic background in the current admixed population. The results show that local well-adapted strains, which have never been intensively managed and differentiated into specific breeds, exhibit large haplotype diversity. They suggest a conservation and recovery approach that does not rely exclusively on the search for the original native genetic background but rather on the identification and removal of common introgressed haplotypes would be more powerful. Successful implementation of such an approach should be based on combining phenotype, pedigree, and genome-wide haplotype data of the breed of interest and a spectrum of reference breeds which potentially have had direct or indirect historical contribution to the genetic makeup of the breed of interest.
Istrian dairy sheep is a local breed essential for the identity and development of the Northern- Adriatic karstic region through high-quality products, primarily the hard sheep artisanal cheese. ...Border changes fragmented the initial Istrian dairy sheep population in three genetically isolated sub-populations in Italy (1000 animals), Slovenia (1150 animals) and Croatia (2500 animals). Due to the drastic reduction of their population sizes and fragmentation, the populations in Croatia and Slovenia are included in governmentally supported conservation programs. The initial subpopulation in Italy was restored after near extinction with stock from Slovenia, and is used today in meat production. The aim of this study was to provide an initial understanding of the current genetic structure and distribution of the genetic variability that exists in Istrian sheep by analysing individuals sampled in two regional groups of Istrian sheep from Croatia and Slovenia. Cres island sheep and Lika pramenka sheep were used as out-groups for comparison. Genetic differentiation was analysed using factorial correspondence analysis and structure clustering over 26 microsatellite loci for a total of 104 sheep belonging to three breeds from Croatia and Slovenia. Factorial correspondence analysis and clustering-based structure analysis both showed three distinct populations: Lika pramenka sheep, Cres island sheep and Istrian sheep. We did not find a marked genetic divergence of the regional groups of Istrian sheep. Istrian sheep regional group from Slovenia showed lower genetic variability compared to the one from Croatia. Variability and structure information obtained in this study considered alongside with socio-cultural-contexts and economic goals for the Istrian sheep reared in Croatia and Slovenia indicate that the cross-border exchange of genetic material of animals carrying private alleles among populations would maintain these alleles at low frequencies and minimize the inbreeding rate.
Production data of Bovec and Improved (with East-Friesian) Bovec sheep born between years 1989 and 2006 were used for the analysis of culling dynamics and lifetime production. Lifetime production was ...calculated as the sum of production at each lambing (number of born and liveborn lambs and litter birth weight), weaning (number of weaned lambs and litter weaning weight) or during each lactation (milk yield, fat (6.5 %) and protein (5.8 %) corrected milk yield (FPC; Pulina et al., 2005.), and fat and protein yield) for culled sheep. Animals with any missing records from the first till the last lambing, weaning or lactation were removed from the analysis. Animals that left the system of animal recording alive, due to selling or the cancellation of recording by a breeder were also excluded. Dataset included records for 2254 sheep: 1734 of Bovec and 520 of Improved Bovec breed. Data preparation and statistical analysis were performed with the use of a statistical program R (R Development Core Team, 2007.) and additional packages Zelig (Imai et al., 2007; Bailey and Alimadhi, 2007; Imai et al., 2008) and lme4 (Bates and DebRoy, 2004; Bates, 2007). Results have shown that in the period ≤1996 Bovec breed had on average 4.4 lactations in their lifetime, which was almost one lactation more than in Improved Bovec breed. In the period after the year 1996 the highest proportion of animals were culled in the first lactation (as expected due to culling dynamics), with slightly higher proportion in Improved Bovec breed than in Bovec breed. Lifetime number of born, liveborn and weaned lambs was higher for about one lamb in Improved Bovec breed. Lifetime lamb weight gain did not differ between breeds, due to the high frequency of early weaning in Improved Bovec breed. During lifetime, Improved Bovec sheep produced around 200 kg (~34 %) more milk, around 190 kg (~32 %) more FPC milk, around 12 kg (~32 %) more milk fat, and around 10 kg (~34 %) more milk protein than Bovec breed. However, if the mean metabolic weight of breeds is taken into account the difference in milk production amounts to only ~6 % (~2 % for FPC milk). These results show that Bovec breed has satisfactory milk production, but too low body weight for intensive milk production. On the other hand, low body weight makes this breed suitable for extensive farming in hill and mountain areas. Improved Bovec breed has good results in Slovenian conditions, due to the similarity of environmental conditions with East Friesian’s country of origin.
Different AT milk recording schemes, with purpose of detection of scheme with the highest lactation milk yields prediction accuracy as well as with simplest practice application, were compared in ...this study. Analysed data were collected from November 2004 till November 2006 on 15 family farms in Croatia according to A4 milk recording scheme by the field assistants of the Croatian Livestock Centre. Measuring at test-day included measurement of milk yield and taking one sample for milk composition analysis at each milking (evening and morning). During research, total of 769 cows were included in research. More than 50 % of all cows were Holstein breed (58.9 %), while the rest of the cows belonged to the Simmental breed. For prediction of daily milk yields two methods were used: M I. = linear regression of daily on partial values with taking into account the interval between successive milkings; M II. = doubling of partial values. The Test Interval Method (TIM) was used for prediction of lactation values. As evaluation criteria for comparison of schemes, correlation and difference between estimated and true milk yields were used. Scheme S II., that is use of first morning, then evening test-day record, in case of doubling the partial yields, showed as scheme with the highest prediction accuracy. Regardless of milk recording scheme, use of method M I. in daily milk yields prediction, resulted in high accuracy and low milk yields, milk fat and protein bias prediction in standard lactation. Research results implicate the use of method M I. in daily milk yields prediction, as well as possibility of different AT milk recording schemes combination in practice.
Thirteen improved Jezersko-Solčava lambs (JSR) and 16 crossbreds with Charollais (JSRxCH) were used to evaluate the effect of genotype and sex on carcass traits. Lambs were weaned at around 60 days ...of age. They were fed with commercial concentrate and hay ad libitum and slaughtered at 30 kg of average live weight at 103 days of age. Crossbred lambs had at the same live weight at slaughter better conformation (9.19 on 15 points scale) than JSR lambs (7.58). Carcasses of crossbred lambs had lower proportion of fat in hind leg and lower proportion of kidney fat. Female lambs had better dressing proportion (46.25%) than male lambs (42.72%). Females had also higher scores for both internal and subcutaneous fatness and higher percentage of kidney fat. They had higher proportion of fat and lower proportion of bone in hind leg.
The study was conducted on 51,154 Holstein primiparous cows. The purpose of the study was to estimate the impact of time elapsed from last milking until scoring on the properties of udder ...conformation traits (fore udder attachment, rear udder height, rear udder width, udder depth, and central ligament). The purpose was also to consider the benefits of including this effect in statistical models for estimation of genetic parameters in dairy cattle. A significant (P<0.001) positive linear relationship between scores of udder traits and the time of the scoring was determined. Rear udder height (b = 0.088) and rear udder width (b = 0.091) were affected the most, with the prolongation of time of scoring regarding previous milking. The investigated effect only affected the residual component of variance. Other components of variance did not change considerably when the time from milking to scoring was fitted into a basic statistical model. Estimated heritabilities ranged from 0.15 to 0.27. Slightly higher estimates of heritabilities for all traits, except for the central ligamentum, were determined when this effect was fitted into the model. Udder depth was found to be in strong negative genetic correlation with fore udder attachment (r = -0.436). An almost negligible negative genetic correlation between udder depth and rear udder width was determined (r = -0.086). Genetic correlations between all other traits were positive and low to moderate (r = 0.15-0.54). The investigated effect did not noticeably affect estimates of genetic correlations between udder conformation traits. Key words: udder conformation traits, time interval, model, genetic evaluation Istrazivanje je provedeno na 51154 krava holstajn-frizijske pasmine. Cilj je bio istraziti utjecaj vremena proteklog od posljednje muznje do ocjenjivanja na linearne ocjene vimena (vezanost prednjeg vimena, visinu straznjeg vimena, sirinu straznjeg vimena, dubinu vimena i izrazenost centralnog ligamenta). Cilj je takoder bio razmotriti prednosti ukljucivanja spomenutog utjecaja u statisticki model za procjenu genetskih pokazatelja. Preliminarnom analizom su utvrdene vece prosjecne ocjene svih svojstava koja su ocijenjena kasnije u odnosu na prethodnu muznju. Utvrdena je statisticki znacajna (P<0,001) linearna regresija svih ocjena vimena na vremenski interval izmedu muznje i ocjenjivanja. Vrijeme proteklo od muznje do ocjenjivanja najvise je utjecalo na ocjene visine (b = 0,088) i sirine (b = 0,091) vimena. Ukljucivanjem spomenutog ucinka u statisticki model za genetsko vrednovanje zivotinja smanjila se rezidualna varijanca dok se ostale komponente varijance nisu znacajno promijenile. Procijenjeni su heritabiliteti u rasponu od 0,15 do 0,27. Heritabiliteti procijenjeni prosirenim modelom bili su veci za sva istrazivana svojstva osim za centralni ligament. Utvrdena je znacajna negativne genetska korelacije dubine vimena s vezanosti prednjeg vimena (r = -0,436) te gotovo zanemariva (r = -0,086) negativna genetska korelacija dubine vimena sa sirinom straznjeg vimena. Ostala istrazivana svojstava bila su pozitivno genetski korelirana (r = 0,15-0,54). Istrazivani ucinak nije znacajno utjecao na procjene genetskih korelacija. Kljucne rijeci: konformacijska svojstva vimena, vremenski interval, model, genetsko vrednovanje
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