Evaluation of chromosomal instability in somatic cells of farmed foxes

The micronucleus (MN) test is a common tool used to evaluate cellular genetic instability at the chromosomal level. It determines the effect of physical, chemical and environmental factors on DNA, and thus the body's individual resistance to harmful substances. The karyotypes of blue and silver foxes and their interspecific hybrids are characterized by morphological and structural variation. This variation is partly attributable to the presence of chromosomal polymorphism, which may significantly influence the stability of genetic material in the cells of these species. The objective of the study was to evaluate genetic material stability in selected Canidae species. To this end, analyses using the MN test were performed. Binucleated cells (BNCs) were analysed in microscopic preparations, and the number of micronuclei was determined within these cells. For the proportions of both MN and BNCs, highly significant differences were observed between the fox species. The interspecific hybrids differed from the other fox species in MN percentage. The lowest average was noted in blue foxes (3.33) and the highest in interspecific hybrids (15.21).</p

Estimation of daily milk yield based on morning and evening milking

Celem pracy było porównanie kilku metod szacowania dobowej wydajności mleka na podstawie jednego udoju: porannego lub wieczornego, krów ocenianych metodą AT4. Materiał stanowiły dane z robotów udojowych udostępnione przez Polską Federację Hodowców Bydła i Producentów Mleka (PFHBiPM). Wybrano 43 309 udojów wykonanych między 5. a 305. dniem doju dla krów z jednym lub dwoma udojami w ciągu doby. Odstęp między danym dojem a poprzednim podzielono na klasy (MIC), a laktacje podzielono na 10 miesięcznych faz. Wydajności dobowe szacowano na podstawie równań regresji liniowej. Porównano 3 równania: w obrębie laktacji pierwszych i pozostałych (wariant 1, modele 1-3) lub łącznie dla wszystkich laktacji (wariant 2, modele 4-6). Współczynniki dla modelu 1. wyznaczono w obrębie pory doju, klasy MIC i fazy laktacji. Współczynniki modelu 2. obliczono w obrębie pory doju, a odstęp między danym dojem i poprzednim uwzględniono jako dodatkową współzmienną. Współczynniki dla modelu 3. wyznaczono w obrębie pory doju, klasy MIC, a fazę laktacji zastąpiono regresją na dzień doju. Rekomendowany do wdrożenia jest model 1., który stanowi prosty model regresji, łatwy do implementacji w praktyce. Wyznaczenie współczynników w obrębie laktacji podzielonych na pierwsze i pozostałe pozwoli na dokładniejsze szacowanie wydajności dobowej.The aim of the study was to compare several methods for estimating daily milk yield on the basis of one milking – morning or evening – of cows evaluated by the AT4 method. The material consisted of data from milking robots, obtained from the Polish Federation of Cattle Breeders and Dairy Farmers (PFCBDF). A total of 43,309 milkings carried out between the 5th and 305th day of milking in cows milked once or twice a day were selected. The intervals between a given milking and the previous one were assigned to classes (MIC), and the lactations were divided into 10 one-month stages. Daily yield was estimated on the basis of linear regression equations. Three equations were compared: for first and later milkings (variant 1, models 1-3) or for all lactations combined (variant 2, models 4-6). The coefficients for model 1 were determined for time of milking, MIC and stage of lactation. The coefficients for model 2 were calculated for time of milking, while the interval between a given milking and the previous one was taken into account as an additional covariate. The coefficients for model 3 were determined for time of milking and MIC, while stage of lactation was replaced with day of milking. Implementation of model 1 is recommended, as it is a simple regression model that is easy to implement in practice. Determination of coefficients for lactations divided into first and later lactations allows for more precise estimation of daily milk yield

Genetic relationships of body condition score and locomotion with production, type and fertility traits in Holstein-Friesian cows

New traits are sought to add in breeding goals to prevent worsening health and fertility of Polish Holstein-Friesian cows. The objectives of this study were to estimate genetic parameters for body condition score (BCS) and locomotion (LOC) and their relationship with other type traits, milk and fertility traits, and to show genetic trends for BCS and LOC in Polish Holstein-Friesian population. Data on 317 028 Holstein-Friesian cows, born from 2010 through 2015 in 11 792 herds, were collected. All cows were scored for BCS and 43% of them for LOC. All records comprised lactational yields of milk, fat and protein, content of fat and protein and somatic cell count from the first three lactations, stature, five composite and 16 linear conformation traits, and four fertility traits. Genetic parameters were estimated using a Bayesian method with Gibbs Sampling, generating 100 000 samples in each of four steps: BCS and LOC with five composite conformation traits, BCS and LOC with 16 linear conformation traits, BCS and LOC with production traits, and BCS and LOC with four fertility traits. The linear model for BCS and LOC contained fixed effects of herd-year-season-classifier and lactation stage, fixed linear and quadratic regressions on age at calving, fixed linear regression on the percentage of Holstein-Friesian genes, and random additive genetic effect. Breeding values for BCS and LOC were calculated using the same model as used for estimation of genetic parameters. Genetic trends for BCS and LOC, defined as regression coefficients of mean breeding value on birth year, were examined. BCS was a moderately heritable trait (0.19) and was genetically correlated with non-return rate until 56 days after first insemination for cows (−0.32) and with days open (−0.22), so selection for BCS might have a favourable correlated effect on fertility. LOC, lowly heritable (0.06), was relatively strongly genetically correlated with feet-and-legs traits (from 0.48 to 0.93, ignoring sign) and could be included in a selection subindex for feet-and-legs. The positive trend for LOC indicated substantial progress towards the highest genetic value (optimum at the end of the scale), while the small trend for BCS showed a tendency to stabilise the average value in the middle of the scale (optimum for BCS). The estimates of the genetic parameters for BCS and LOC indicate that both traits could contribute to more effective selection to improve fertility (BCS) and legs health (LOC) in the Polish dairy cattle population

Relationships between meat quality traits of Popielno White rabbits

The purpose of the study was to determine the phenotypic correlations between meat quality traits in Popielno White rabbits. The experimental material consisted of 93 Popielno White rabbits (49♀; 44♂). From weaning at 35 days of age until 84 days of age, the animals were housed in a battery system and fed ad libitum with a complete feed containing 10,2 MJ of metabolic energy, 16,5% total protein and 14% crude fibre. The rabbits were slaughtered at 84 days of age with a body weight of about 2,6 kg. The research material was the meat of longissimus lumborum muscle. Meat quality characteristics, i.e. meat acidity, meat colour, shear force, meat texture and cooking loss, were examined. The results were analysed using the SAS package (2014). Many statistically significant relationships were found between the meat quality characteristics of Popielno White rabbits. The results indicate that potential selection towards a change in pH value may adversely affect the meat texture of Popielno White rabbits. Selection to improve the colour of the meat of this breed may have a negative effect on its shear force, hardness and cooking loss. Selection to improve shear force will improve the other texture profile parameters. An improvement in the meat texture parameters of Popielno White rabbits will lead to an improvement in the cooking loss value. Dependencies among meat quality traits in Popielno White rabbits are high enough to be useful in selecting an appropriate breeding method

The effect of breed on litter size and milk yield in rabbits

Celem badań było określenie wpływu rasy na liczebność miotu oraz współczynnik mleczności królic. Materiał badawczy stanowiły samice rasy: kalifornijskiej czarnej (n=16), nowozelandzkiej białej (n=19), popielniańskiej białej (n=24), termondzkiej białej (n=36) oraz belgijskiego olbrzyma szarego (n=14), wraz z potomstwem. Badania obejmowały 3 kolejne mioty samic. W celu obliczenia współczynnika mleczności samic ważono mioty do 24 godzin od wykotu oraz w 21. dniu życia. Z przeprowadzonej analizy wynika, że największą liczebnością charakteryzowały się mioty samic rasy belgijski olbrzym szary (9,09 szt.), natomiast najmniejszą – rasy nowozelandzkiej białej (6,47 szt.). Dla samic rasy termondzkiej białej, kalifornijskiej czarnej i popielniańskiej białej średnia liczebność miotu wynosiła, odpowiednio: 7,78, 7,50 i 7,46 sztuk. Największym współczynnikiem mleczności charakteryzowały się samice rasy termondzkiej białej (3,76), natomiast najmniejszym – samice rasy belgijski olbrzym szary (3,18).The aim of the study was to determine the influence of breed on litter size and milk yield in rabbits. The following breeds were analysed in the study: Californian Black (n=16), New Zealand White (n=19), Popielno White (n=24), Blanc de Termonde (n=36) and Belgian Giant Grey (n=14). The study was conducted on three consecutive litters. The litters were weighed up to 24 hours from birth and at 21 days of age to calculate the milk yield. The Belgian Giant Grey females were found to have the largest litters (9.09 pups), while the litters of the New Zealand White rabbits were the smallest (6.47). In the case of the Blanc de Termonde, Californian Black and Popielno White females, the mean litter size was 7.78, 7.50 and 7.46, respectively. The Blanc de Termonde rabbits had the highest milk yield (3.76) and the Belgian Giant Grey females had the lowest (3.18)

The effect of breed and sex on the texture of rabbit meat

Celem pracy było określenie wpływu rasy i płci na teksturę mięsa króliczego. Materiał badawczy stanowiły króliki rasy belgijski olbrzym szary (n=30; 18♂, 12♀), kalifornijski czarny (n=26; 18♂, 8♀), nowozelandzki biały (n=19; 12♂, 7♀), popielniański biały (n=64; 31♂, 33♀) oraz termondzki biały (n=39; 17♂, 22♀). Zwierzęta ubijano w 12. tygodniu życia. Po 24-godzinnym dojrzewaniu mięsa w warunkach chłodniczych pobierano do badań próbki mięśnia najdłuższego lędźwi (m. longissimus lumborum). Pomiar siły cięcia i profilowej analizy tekstury (TPA) wykonano za pomocą teksturometru TA.XTplus (Stable Micro Systems). Mierzono takie parametry, jak: siła cięcia (kg), twardość (kg), sprężystość, spójność, żujność (kg). Wszystkie parametry tekstury mięsa oraz siły cięcia obliczono automatycznie, przy pomocy programu Exponent for Windows ver. 6.1.10.0 (Stable Micro Systems). Na podstawie przeprowadzonej analizy wykazano, że rasa ma istotny wpływ jedynie na twardość mięsa. Mięso królików termondzkich białych było najtwardsze (12,06 kg), natomiast najmniejszą twardością charakteryzowało się mięso belgijskich olbrzymów szarych (8,87 kg). Płeć nie różnicowała parametrów tekstury mięsa.The aim of this study was to determine the influence of breed and sex on texture parameters of rabbit meat. The study was conducted on rabbits of the breeds Belgian Giant Grey (n=30; 18♂, 12♀), Californian Black (n=26: 18♂, 8♀), New Zealand White (n= 19: 12♂, 7♀), Popielno White (n=64; 31♂, 33♀) and Blanc de Termonde (n= 39; 17♂, 22♀). The animals were slaughtered at 12 weeks of age. After 24-hour ageing under refrigeration, samples of the loin (m. longissimus lumborum) were collected for analysis. Texture Profile Analysis (TPA) was performed using a TA.XTplus texture analyser (Stable Micro Systems). Shear force (kg), hardness (kg), springiness, cohesiveness and chewiness (kg) were measured. All texture parameters were calculated automatically using Exponent for Windows ver. 6.1.10.0 (Stable Micro Systems). The analysis showed that the breed significantly influenced only the hardness of the rabbit meat, which was highest for Blanc de Termonde (12.06 kg) and lowest for Belgian Giant Grey (8.87 kg). Sex had no significant influence on texture parameters