Klemen Potočnik

Fatty acid composition and sensory analysis in Boer kids meat

Abstract. This study was undertaken to characterize the fatty acid profile and sensory properties of longissimus dorsi (LD) muscle of Boer kids as affected by sex (17 male, 15 female) and slaughter weight (pre-weaned 20 kg, post-weaned 30 kg). Regarding sex differences, higher percentage amounts of lauric, myristic, pentadecanoic, linolenic and docosapentaenoic acids were found in LD muscle of male compared to female kids, whereas greater amounts of oleic acid were detected in LD muscle of female kids. Also, LD of male kids contained higher percentage amounts of saturated (SFA), polyunsaturated (PUFA) and n-3 polyunsaturated fatty acids (n-3 PUFA) while higher amounts of monounsaturated fatty acids (MUFA) were detected in LD of female kids. Regarding slaughter weight, percentage amounts of lauric, myristic, margaric, pentadecanoic, linolenic, linoleic, arachidonic and docosapentaenoic acids significantly decreased with age (P≤0.001), while percentage amounts of heptadecenoic and oleic acids significantly increased (P≤0.001). LD muscle from lighter kids contained higher percentage amounts of SFA and PUFA, while heavier kids had higher percentage amounts of MUFA and n-3/n-6 fatty acid ratio. Except meat colour, sensory traits (marbling, off-odour, flavour, juiciness and tenderness) were neither significantly affected by sex nor slaughter age.

Differences in response to heat stress due to production level and breed of dairy cows

The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

Test-day records as a tool for subclinical ketosis detection.

The prevalence, as well as the effect of subclinical ketosis on daily milk yield, was observed using 1.299, 630 test-day records collected from January 2000 to December 2005 on 73, 255 Slovenian Holstein cows. Subclinical ketosis was indicated by the fat to protein ratio (F/P ratio) higher than 1.5 in cows that yielded between 33 to 50 kg of milk per day (Eicher, 2004). The ketosis index was defined in relation to the timing of subclinical ketosis detection to the subsequent measures of test-day milk yields. The effect of subclinical ketosis on test day milk yields were studied separately for each parity using the mixed model analysis. The statistical model included the fixed effect of ketosis index, calving year-month, lactation stage and random effect of animals included in the study. The prevalence peak of subclinical ketosis occurred in the first month of lactation. Subclinical ketosis had a significant negative effect on daily milk yield. Decrease in milk yield in the amount of 4.21 kg/day, 2.73 kg/day ; 2.78 kg/day ; 2.83 kg/day ; and 3.72 kg/day in each parity were determined within 35 days after the detection of subclinical ketosis. The decrease continued in subsequent milk controls. The research results show that test-day records could be a useful tool for early detection of subclinical ketosis.

11. Effect of Heat Stress on Metabolic Disorders Prevalence Risk and Milk Production in Holstein Cows in Croatia

Abstract The objectives were to evaluate the effect of heat stress on daily milk traits (yield, fat and protein content, F/P ratio) as well as to determine the differences in metabolic disorders (acidosis, ketosis) prevalence risk regarding the heat stress conditions. For statistical analysis 1,187,781 test-day records of milk, fat, and protein from 89,030 Holsteins reared on 6,388 farms provided by the Croatian Agricultural Agency, were used. Based on the results it could be concluded that heat stress condition causes decline of daily milk yield and components as well as increase of acidosis risk regardless of the lactation stage and increase of ketosis risk during mid-lactation. The research results point out that the test-day records and environmental measurements collected in regular milk recording could be used as a tool for dairy herd monitoring enabling the early detection of unfavourable environmental conditions and the subclinical disorders. Since environmental conditions significantly affect daily milk yield and components, and consequently F/P ratio, further research with the purpose of detailed formulation of metabolic disease risk in relation to the environmental conditions is needed.

Physicochemical properties of horse meat as affected by breed, sex, age, muscle type and aging period

The effects of breed, sex, age, muscle type (longissimus thoracis; LT vs semitendinosus; ST) and post mortem aging period (14 vs 28 days) on the physicochemical properties of horse meat were investigated. A total of 53 horses (21 females and 32 males) categorised into three groups (cold-blooded, CB; Posavje, P; crossbred, CS) were involved in this study. ST muscles showed a higher pH value, a greater intensity of lightness (L*) and yellowness, higher cooking losses and shear force values, and lower thawing losses than LT muscles. The breed affected only muscle redness, whereas sex had a minor effect on drip loss. An extended aging period was associated with higher thawing and cooking losses. An increase of age was followed by a decrease in pH value and L* value, and an increase in cooking loss and Warner–Bratzler shear force. An investigation of the interaction between muscle and aging showed that ST muscle with an aging period of 14 days had the lowest thawing losses. Among the numerous factors that can influence horse meat quality, the most important ones are age at slaughter and muscle type; these factors must be considered in the routine slaughtering practice and in further research.

The effect of sex and age at slaughter on some carcass and meat quality traits of Boer kids

This study investigated some carcass and meat quality traits of Boer kids (17 male and 17 female) at two different average slaughter ages (83 and 139 days). Jointed cuts of half carcasses arranged from the greatest to the smallest were: hind leg (28.5%), rib and flank (21.2%), shoulder (19.3%), back (8.5%), loin (7.9%), neck (7.6%) and chuck (3.4%). Male kids had significantly higher percentage of the neck cuts (p≤0.001) while females had significantly higher percentage of rib and flank cuts (p≤0.05). At higher slaughter ages neck (p≤0.05) and chuck (p≤0.001) percentages significantly decreased and rib and flank (p≤0.001) percentage significantly increased. On average, hind leg had 72.2 % of muscle, 8.6 % of fat and 18.8 % of bone. Female kids had higher muscle and lower bone hind leg content than males (p≤0.01). Hind leg bone content significantly decreased at higher slaughter age (p≤0.01). Meat from male kids displayed significantly higher cie L*(p≤0.001) and b*(p≤0.05) values than females. At higher slaughter age L* values significantly decreased (p≤0.01) while a* and b* values significantly increased (p≤0.001; p≤0.01).

Analysis of inbreeding in Slovenian Haflinger population

Abstract The pedigree information of 3613 animals registered in the Slovenian Haflinger stud book from birth year 1905 to 2008 were analysed using PROC INBREED in SAS/ STAT with the purpose of analysis of inbreeding level in Slovenian Haflinger population. Relationship (R) analysis was restricted to possible mating partners that had offspring born between 2004 and 2008 (i.e., 323 mares and 58 stallions). An increasing trend of inbreeding coefficients (F) was observed in recent years, although a generally low F was detected. Mean values of R between possible mating partners were mostly around zero, while maximum values ranged up to 0.63. The development of application that would ease the calculations of F and R could help breeders to prevent related mating in the future.