Genetic Relationships under Different Management Systems and their Consequences for Dairy Cattle Breeding

Advances in breeding and management resulted in a considerable increase of production traits in Austrian dairy cattle. Besides, low input systems were also established. Possible genotype by environment interactions (G x E) and genetic antagonisms dependent on production level might indicate the need for separate breeding programmes for dairy farms differing in management intensity. Thus, G x E and genetic correlations (ra) between milk yield and selected fitness traits were estimated for Upper Austrian Fleckvieh cattle under high and low production levels. Data of the current herdbook cow population and their dams were extracted. Two data sets were selected based on the herd average of milk; extensive (≤6,000 kg herd average) and intensive (≥9,000 kg herd average) farms. Yield deviations were used for the analysis of yield traits, functional longevity, reproduction traits and milking speed; raw data were used for somatic cell count (SCC). For yield deviations, a model including the effects year of birth (fixed) and animal (genetic, random) was applied, while a model close to the routine evaluation was run for SCC. The lowest ra between extensive and intensive farms was found for protein yield (ra = 0.89) while ra values close to unity were found for all functional traits. Genetic antagonisms between milk yield and functional traits were stronger in intensive systems, however, standard errors were large. Currently, separate breeding programmes for different management intensities do not seem to be necessary

Inbreeding and its Effect on Performance Traits in Austrian Meat Sheep

The aim of this study was to evaluate the level of inbreeding of meat performance tested herd book sheep in Austria and to evaluate the effect of individual inbreeding on growth and CT (computer tomography) scan carcass traits. Performance data (13,614 records, five breeds: Merinoland, Suff olk, Texel, German Blackheaded Meat sheep, Jura) were collected in the years 2000-2010. The traits analysed were live weight and average daily gain, as well as traits of body frame, back fat and eye muscle area, all measured on live animals with CT. Inbreeding coefficients (F) were calculated with the soft ware PEDIG. F was nested within breed and tested in a mixed model using ASReml. Levels of inbreeding were low with O F of 1.5-3.1%. Only few traits were significantly affected by inbreeding. Both positive and negative effects were found. The effects were small, most oft en nonlinear and vary across breeds. Inbreeding and its effects on performance traits do not seem to be an issue in Austrian meat sheep populations at the moment. However, monitoring and further analyses are recommended

Calving Performance in the Endangered Murboden Cattle Breed: Genetic Parameters and Inbreeding Depression

Calving is a key event on any cattle farm, with both economic and animal welfare consequences when complications arise. Although mostly reported in highly selected breeds, problematic calving performance is also a worry to the unselected dualpurpose Murboden breed, local to Austria. This study presents genetic parameter estimates for calving ease and stillbirth in Murboden cattle. Furthermore, a potential effect of inbreeding on the breeds’ calving performance is evaluated. Results show a moderate direct and maternal heritability (0.18±0.04; 0.11±0.02) and a significant negative direct-maternal genetic correlation for calving ease (-0.41±0.10). Heritabilities of stillbirth are low yet significant (0.048±0.01; 0.018±0.007). A significant effect of inbreeding was detected on maternal calving ease i.e. the ease with which a dam calves. By categorizing the inbreeding coefficients of the dam in six ascending classes it was shown that calving ease worsens as inbreeding coefficients become larger. Results of this study reveal significant genetic variation in calving performance of the Murboden breed which opens doors for genetic selection. An additional important aspect of this study is that its result on inbreeding depression gives counterweight to the general intuitive notion in literature that high selection for production traits is the major contributor to calving difficulty in dairy and beef cattle breeds worldwide

On the genomic regions associated with milk lactose in Fleckvieh cattle.

ABSTRACT Lactose is a sugar uniquely found in mammals' milk and it is the major milk solid in bovines. Lactose yield (LY, kg/d) is responsible for milk volume, whereas lactose percentage (LP) is thought to be more related to epithelial integrity and thus to udder health. There is a paucity of studies that have investigated lactose at the genomic level in dairy cows. This paper aimed to improve our knowledge on LP and LY, providing new insights into the significant genomic regions affecting these traits. A genome-wide association study for LP and LY was carried out in Fleckvieh cattle by using bulls' deregressed estimated breeding values of first lactation as pseudo-phenotypes. Heritabilities of first-lactation test-day LP and LY estimated using linear animal models were 0.38 and 0.25, respectively. A total of 2,854 bulls genotyped with a 54K SNP chip were available for the genome-wide association study; a linear mixed model approach was adopted for the analysis. The significant SNP of LP were scattered across the whole genome, with signals on chromosomes 1, 2, 3, 7, 12, 16, 18, 19, 20, 28, and 29; the top 4 significant SNP explained 4.90% of the LP genetic variance. The signals were mostly in regions or genes with involvement in molecular intra- or extracellular transport; for example, CDH5, RASGEF1C, ABCA6, and SLC35F3. A significant region within chromosome 20 was previously shown to affect mastitis or somatic cell score in cattle. As regards LY, the significant SNP were concentrated in fewer regions (chromosomes 6 and 14), related to mastitis/somatic cell score, immune response, and transport mechanisms. The 5 most significant SNP for LY explained 8.45% of genetic variance and more than one-quarter of this value has to be attributed to the variant within ADGRB1. Significant peaks in target regions remained even after adjustment for the 2 most significant variants previously detected on BTA6 and BTA14. The present study is a prelude for deeper investigations into the biological role of lactose for milk secretion and volume determination, stressing the connection with genes regulating intra- or extracellular trafficking and immune and inflammatory responses in dairy cows. Also, these results improve the knowledge on the relationship between lactose and udder health; they support the idea that LP and its derived traits are potential candidates as indicators of udder health in breeding programs aimed to enhance cows' resistance to mastitis

Assessment of viability of new born piglets using an adjusted APGAR score

Since decades pig breeding goals have mainly focused on prolificacy. However, large litters can have implications on piglets’ and sows’ welfare. Due to increased litter size viability of piglets may decrease, leading to a higher number of stillborn piglets and increased suckling piglet mortality. Piglet viability can be assessed using an adjusted APGAR score. This score measures in the new born piglet indicators crucial for the ability to survive. So the aim of this paper is to investigate the main effects on piglet viability by using an adjusted APGAR score. For this purpose, 25 sows and 404 born piglets were assessed using an adjusted APGAR scoring system. Every live born piglet was evaluated directly after birth regarding the parameters skin colour, umbilical cord condition, latencies to respiration, first movement, first attempt to stand up and first teat contact. Each parameter was scored from 0 (bad) to 2 (good) according to predefined categories and summed up to an overall APGAR score. The influence of provision of oxytocin or manual intervention during farrowing, care of the new born by the farmer and obstetrics on viability was investigated. It was found, that new born care and the condition of the umbilical cord had the highest influence on piglet viability. Oxytocin and obstetrics had no influence on the viability of piglets and therefore on the APGAR score

Relationships between resistance characteristics of honey bees (Apis mellifera) against Varroa mites (Varroa destructor)

Ectoparasitic mite, Varroa destructor, today is one of the main reasons for colony losses worldwide. This study deals with relationships between measurements of resistance characteristics and measurements of bee infestation. During the trial, 105 Apis mellifera carnica colonies were tested according to AGT (Arbeitsgemeinschaft Toleranzzucht) breeding program. Data of hygienic behavior and mite population growth development were obtained. Further, they were evaluated for the traits SMR (Suppressed Mite Reproduction), recapping behavior (REC) and brood infestation. Significant influences of hygienic behavior, SMR and REC on the mite infestation were considered. SMR and REC show relatively high coefficients of regression on mite infestation values. The results show, that SMR and REC might be suitable selection traits to decrease the mite population growth within the colonies

Forage particle size and forage preservation method modulate lying behaviour in dairy cows

It has been suggested that reducing forage particle size as well as feeding hay compared to silage may improve forage intake. Little is known, however, how such ration characteristics affect other aspects of cattle behaviour. Therefore, this study investigated the lying behaviour of cows in response to particle size reduction (LONG versus SHORT; Trial 1) and preservation method (SILAGE versus HAY; Trial 2) of forages which constituted ≥ 80% of the rations’ dry matter. Two feeding groups with 10 (Trial 1) and 9 Holstein cows each (Trial 2) received the experimental rations for approximately 5 weeks. Cows were housed in a free-stall barn with straw-bedded cubicles and rubberized floor in the alleys. Lying behaviour was recorded using HOBO Pendant® acceleration data loggers during the last 3 weeks of the experimental period as well as for 3 consecutive days during the week preceding the experiment, the latter serving as a baseline covariate to consider individual cow lying behaviour. SHORT-fed cows (Trial 1) had a longer daily lying time (+ 1.1 h/d; P = 0.003) and tended to have more lying bouts (+ 3.1; P = 0.090) than cows fed the LONG ration. In both groups, a preference towards the left lying side (57.4%) was observed. A similar pattern was observed for both groups with regard to rumination time while lying. Cows fed SILAGE or HAY (Trial 2) did not differ with regard to lying times (12.8 h/d). However, cows on HAY tended to lie less on the left side (- 1.1 h/d; P = 0.098) and had less lying bouts per day (- 2.5 bouts/d; P = 0.039). Consequently, these cows showed nearly an equal preference for the left and right lying side with 49.1% and 51.6%, respectively; whereas cows on SILAGE tended to prefer the left lying side (55.6%), also when ruminating. In contrast, cows on HAY tended to reduce rumination time on the left lying side (- 0.61 h/d; P = 0.079). Effects observed may be attributed to changes in eating behaviour as well as the amount of feed ingested in a given time period. Under the conditions investigated, time budgets for lying may be limited and changes of the forage characteristics (e.g. particle size reduction) could mitigate these constraints