Zofia Wielgosz-Groth

The effect of carcass conformation class (EUROP system) on the slaughter quality of young crossbred beef bulls and Holstein-Friesians.

Abstract The objective of this study was to determine the effect of genotype and carcass conformation class on the slaughter quality of 200 young bulls, including 108 crossbred beef bulls and 92 Holstein- Friesians (HF), aged 21-22 months, selected in the lairage. The lean meat content was estimated and body measurements were taken before slaughter. After slaughter, the carcasses were graded according to the EUROP system, and carcass quality parameters were determined. Intramuscular fat was extracted from samples of m. longissimus dorsi, and the fatty acid profile of extracted fat was determined by gas chromatography. 61.11% carcasses of crossbred beef bulls were graded in the conformation class R, and 56.53% carcasses of Holstein-Friesians were classified as O. The majority of carcasses belonged to fat class 2, which was not consistent with intramuscular fat content. Within the same conformation classes, crossbred beef bulls were characterized by higher slaughter quality than Holstein-Friesian bulls. Meat from hybrid beef bulls had a higher (by 0.42% on average) content of fat with a more desirable composition. Since the population size of beef cattle will probably not increase in the nearest future, efforts should be continued to optimize the production of high-quality beef from dairy cattle herds. Streszczenie Badano wpływ genotypu i klasy uformowania tuszy na wartość rzeźną 200 buhajków. W magazynie żywca wybrano sztuki w wieku 21-22 miesięcy, z czego 108 były to mieszańce mięsne a 92 holsztyno- fryzy (ho). Przed ubojem oceniano ich umięśnienie i wykonano pomiary zoometryczne ciała. Po uboju sklasyfikowane tusze według systemu EUROP poddano szczegółowej ocenie wartości rzeźnej. Z próbki mięśnia najdłuższego grzbietu wyekstrahowano tłuszcz śródmięśniowy, w którym metodą chromatografii gazowej określono udział kwasów tłuszczowych. W klasyfikacji EUROP tusze buhajków mieszańców mięsnych w 61,11% uzyskały klasę uformowania R, a tusze holsztyno-fryzów w 56,53% oceniano jako O. W ocenie otłuszczenia dominowała klasa 2. i ocena otłuszczenia nie była zbieżna z zawartością tłuszczu śródmięśniowego. W obrębie jednakowych klas uformowania, mieszańce mięsne charakteryzowały się wyższą wartością rzeźną, w porównaniu z holsztyno-fryzami. Ponadto mięso ich zawierało średnio o 0,42% więcej tłuszczu o korzystniejszym składzie procentowym. Wobec braku realnych perspektyw na szybkie zwiększenie się wielkość populacji bydła ras mięsnych, należy prowadzić badania w kierunku opracowania metod optymalnej produkcji wołowiny o podwyższonej jakości w oparciu o stada mleczne.

The Effect of Slaughter Weight and Fattening Intensity on Changes in Carcass Fatness in Young Holstein-Friesian Bulls

The objective of this study was to determine the effect of body weight (BW) at slaughter and fattening intensity on carcass fatness and meat fatty acid profile in young Holstein-Friesian bulls. One-hundred bulls fattened on two levels of intensity a semi-intensive (SI) and an intensive (I) were used. Fattening was carried out to BW of 500, 550, 600, 650 and 700 kg. Live ultrasound measurements were performed to determine back fat thickness. Carcass dressing percentage, carcass conformation and fatness, intramuscular fat content of m. longissimus dorsi and fatty acid profile (by gas chromatography) were determined after slaughter. Intensively fattened bulls were characterised by a greater carcass dressing percentage – by 1.17% on average, greater carcass conformation scores, greater external fat thickness and a greater intramuscular fat content than bulls SI fattened. Fat from intensively fattened bulls contained higher levels of polyunsaturated fatty acids (PUFAs) – by 0.96/100 g on average. Semi-intensive fattening contributed to a decrease in the n-6/n-3 PUFA ratio and to a significant increase in the concentrations of C18:2 and C20:4 fatty acids. Regardless of the fattening intensity, the n-6/n-3 ratio was greater in heavier animals. The best results were achieved when young Holstein-Friesian bulls were fattened intensively to BW of 650 kg.

The Effect of Slaughter Season on the Fatty Acid Profile in Four Types of Fat Deposits in Crossbred Beef Bulls

The objective of this study was to determine the effect of slaughter season on the fatty acid profile in four types of fat deposits in crossbred (Polish Holstein Friesian Black-and-White×Limousine) beef bulls. The percentage share of fatty acids was determined by gas chromatography and were divided into the following categories of fatty acids: saturated (SFAs), unsaturated (UFAs), monounsaturated (MUFAs), polyunsaturated (PUFAs), desirable hypocholesterolemic (DFAs) and undesirable hypercholesterolemic (OFAs), n-3 and n-6. Perinephric fat was characterized by the highest SFA concentrations (59.89%), and subcutaneous fat had the highest MUFA content (50.63%). Intramuscular fat was marked by a high percentage share of PUFAs and the highest PUFA/SFA ratio. The slaughter season had a significant effect on the levels of C18:3, C20:4 (p≤0.01) and conjugated linoleic acid (p≤0.05). There was an interaction between the slaughter season and fat type for the content of C20:4 (p≤0.01) and C20:5 (p≤0.05). The results of this study show that beef from cattle slaughtered in the summer season has a higher nutritional value and more health-promoting properties.

Fatty acid profiles of intramuscular, intermuscular, external and internal fat in Polish Holstein-Friesian × Hereford bulls and steers fed grass silage-based diets supplemented with concentrates

This paper determined the impact of gender and feeding intensity on the profile of fatty acids in different types of fat deposits. The studies were conducted with 20 young bulls and 20 steers, which were Polish Holstein-Friesian and Hereford crossbreds fattened intensively – grass silage ad libitum and concentrate covered 50% of the net energy requirement in fattened cattle or semi-intensively – concentrate covered 30% of the net energy. The fatty acid profile in intramuscular, intermuscular, external and internal fat was determined. The content of intramuscular fat was lower (P < 0.001) in the longissimus muscle in the bulls (1.74%) than in the steers (3.71%). In fat of steers, the proportion of monounsaturated fatty acids was higher whereas in fat of bulls, the content of polyunsaturated fatty acids was higher. Generally the impact of the location of fat depots on the profile of fatty acids was statistically significant (P < 0.001) but there was no effect of feeding intensity.

Prediction of the carcass value of young Holstein-Friesian bulls based on live body measurements.

Abstract The aim of this study was to determine the suitability of ultrasound and zoometric measurements and visual muscle scoring for predicting the carcass value of 167 young Holstein-Friesian (HF) bulls. Zoometric and ultrasound measurements were performed and live muscle scoring was estimated before slaughter. After slaughter, hot carcass weight (HCW) was determined and carcasses were assigned to conformation and fat classes according to the EUROP system. Multiple regression equations were derived to estimate the weight, conformation and fatness of carcasses. HCW was estimated using the following equations: Ŷ = 1.507x1 + 1.103x2 + 4.043x3 + 5.53x4 + 0.379x5 + + 8.076x6 - 678.93 (R2=0.892; Sy = 16.28) and Ŷ = 2.525x4 + 0.579x7 + 0.451x8 - 134.17 (R2=0.943; Sy = 11.84); independent variables x1 - height at sacrum (cm); x2 - chest girth (cm); x3 - pelvic width (cm); x4 - pelvic length (cm); x5 - thickness of M. gluteo-biceps (mm); x6 - intravital muscle scoring (points); x7 - thickness of M. longissimus dorsi (mm); x8 - live weight (kg). Validation of the first regression equation revealed overestimation of HCW by 1.25% on average, while validation of the second equation revealed its underestimation by 1.85% on average. It was found that intravital muscle scoring and selected ultrasound and zoometric measurements of HF bulls can be used in formulating regression equations for predicting the carcass value of live animals. The proposed models enable predicting the carcass value of young bulls with satisfactory accuracy, thus contributing to an objective live beef cattle assessment

Fattening performance of crossbred (Polish Holstein-Friesian x Hereford, Limousin or Charolais) bulls and steers offered high-wilted grass silage-based rations

7 CHILEAN JOURNAL OF AGRICULTURAL RESEARCH 76(1) JANUARY-MARCH 2016 3 ULY-SEPTEMBER In Poland beef cattle are usually fed high-wilted grass silage offered ad libitum and supplemented with concentrate, whereas ‘Limousin’, ‘Charolais’ and ‘Hereford’ bulls are the most frequently crossed with dairy cows to produce beef hybrids. The aim of this study was to determine the fattening performance of hybrids produced by crossing ‘Polish Holstein-Friesian’ (PHF) cows with ‘Hereford’ (HH), ‘Limousin’ (LM) and ‘Charolais’ (CH) bulls, fed silage made from high-wilted grass and supplemented with a small amount of concentrate, depending on sire breed and category. The experimental materials comprised 24 bulls and 24 steers, including 8 PHF × HH, 8 PHF × LM and 8 PHF × CH crosses with initial body weight of approximately 300 kg in each group. The animals were fed grass silage with a DM content of 417 g kg-1, supplemented with concentrate at 35 g DM kg-1 W0.75, for 250 d. Steers were characterized by higher total DM intake per unit of metabolic body weight (P < 0.05): 92.8 vs. 87.0 g; 94.1 vs. 84.6 g; 88.6 vs. 87.0 g (PHF × HH; PHF × LM; PHF × CH, respectively) and bulls – by higher average carcass weight gains (P < 0.01): 700 vs. 631 g; 654 vs. 579 g; 633 vs. 574 g and carcass dressing percentage (P < 0.01): 60.0 vs. 56.4%; 60.2 vs. 58.9%; 60.2 vs. 56.6% (PHF × HH; PHF × LM; PHF × CH, respectively) and better (P < 0.01) silage DM, total DM, crude protein, and net energy utilization. Sire breed had no significant effect on the analyzed parameters of fattening performance but numerically PHF × HH crosses had the highest productivity parameters.

Impact of early castration and health status on the performance of Holstein-Friesian and beef crossbred calves

Abstract Introduction: This article presents the analysis of the correlation between the category and health status of calves and the results of their rearing and levels of selected blood parameters. Material and Methods: The study included 105 Polish Holstein-Friesian and beef (Limousine, Charolaise and Hereford) crossbred calves. Young bulls were purchased at the age of two to four weeks. The animals underwent quarantine, were dehorned, and 46 young bulls were castrated. The germ horns were removed by burning out. Castration was carried out with a bloodless method using a rubber band. The calves were kept in groups and fed a milk replacer administered via teats from automated milk-feeding stations. After the period of milk feeding, the calves were fed grass silage ad libitum and a concentrate at 2.5 kg/animal/day. The calves were weighed every two weeks. Blood for analyses was sampled at 43 d of age. Results: After the rearing period finished at the age of six months, young bulls and steers had similar body weights (176.17 and 176.55 kg) and approximate average daily weight gains from birth (0.756 and 0.767 g/day). The healthy calves at six months of age weighed 180.47 kg, whereas the animals which at least once suffered from some diseases during rearing were lighter by approx. 30 kg (P ≤ 0.01). A statistically significant (P ≤ 0.01) difference was found for the count of red blood cells and white blood cells. In comparison with healthy individuals, the diseased animals had less RBC (8.33 and 9.42 1012/L respectively) and more WBC (27.03 and 12.26 109/L respectively). Conclusion: Castration of young bulls did not have any impact on the results of rearing and health status of the calves. The magnitude of the analysed parameters depended on the health status of the calves. Thus RBC and WBC parameters may be used to predict the health status of calves during rearing.