Association of Length of Pregnancy with Other Reproductive Traits in Dairy Cattle

Nogalski, Zenon,Piwczynski, Dariusz Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.1

The experiment involved observations of 2,514 Holstein-Friesian cows to determine the effects of environmental factors (cow's age, calving season, weight and sex of calves, housing system) and genetic factors on gestation length in dairy cattle and the correlation between gestation length and other reproductive traits (calving ease, stillbirth rates and placental expulsion). Genetic parameters were estimated based on the sires of calved cows (indirect effect) and the sires of live-born calves (direct effect). The following factors were found to contribute to prolonged gestation: increasing cow's age, male fetuses and growing fetus weight. Optimal gestation length was determined in the range of 275-277 days based on calving ease and stillbirth rates. The heritability of gestation length was estimated at 0.201-0.210 by the direct effect and 0.055-0.073 by the indirect effect. The resulting genetic correlations suggest that the efforts to optimize (prolong) gestation length could exert an adverse influence on the breeding value of bulls by increasing perinatal mortality and calving difficulty. The standard errors of the investigated parameters were relatively high, suggesting that any attempts to modify gestation length for the purpose of improving calving ease and reducing stillbirth rates should be introduced with great caution.

The Effect of Body Energy Reserve Mobilization on the Fatty Acid Profile of Milk in High-yielding Cows

Nogalski, Zenon,Wronski, Marek,Sobczuk-Szul, Monika,Mochol, Magdalena,Pogorzelska, Paulina Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.12

We investigated the effect of the amount of body condition loss in the dry period and early lactation in 42 high-yielding Holstein-Friesian cows on milk yield and the share of fatty acids in milk fat. Energy reserves were estimated based on the body condition scoring (BCS) and backfat thickness (BFT). Milk yield and milk composition were determined over 305-d lactation. From d 6 to 60 of lactation, the concentrations of 43 fatty acids in milk fat were determined by gas chromatography. Cows were categorized based on body condition loss from the beginning of the dry period to the lowest point of the BCS curve in early lactation into three groups: low condition loss group (L) ${\leq}0.5$ points (n = 14); moderate condition loss group (M) 0.75 to 1.0 points (n = 16) and high condition loss group (H) >1.0 points (n = 12). Cows whose body energy reserves were mobilized at 0.8 BCS and 11 mm BFT, produced 12,987 kg ECM over 305-d lactation, i.e. 1,429 kg ECM more than cows whose BCS and BFT decreased by 0.3 and 5 mm, respectively. In group H, milk yield reached 12,818 kg ECM at body fat reserve mobilization of 1.3 BCS and 17 mm BFT. High mobilization of body fat reserves led to a significant (approx. 5%) increase in the concentrations of monounsaturated fatty acids-MUFA (mostly $C_{18:1}$ cis-9, followed by $C_{18:1}$ trans-11), a significant decrease in the levels of fatty acids adversely affecting human health, and a drop in the content of linoleic acid, arachidonic acid and docosahexaenoic acid in milk fat. In successive weeks of lactation, an improved energy balance contributed to a decrease in the concentrations of unsaturated fatty acids (UFA) and an increase in the conjugated linoleic acid (CLA) content of milk fat.

The effect of gender status on the growth performance, carcass and meat quality traits of young crossbred Holstein-Friesian×Limousin cattle

Pogorzelska-Przybylek, Paulina,Nogalski, Zenon,Sobczuk-Szul, Monika,Momot, Martyna Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.5

Objective: The objective of this study was to compare growth performance, carcass traits and meat quality in young bulls, steers and heifers produced by crossing Limousin bulls with Holstein-Friesian cows, fattened semi-intensively and slaughtered at 18 months of age. Methods: Thirty-one young calves were reared in a conventional production system, and were fed milk replacer, hay and concentrate. At 6 months of age, the animals were divided into groups based on gender, and were fed a total mixed ration composed of grass silage, concentrates I and II in a semi-intensive production system. At the end of the fattening period (18 months), the animals were slaughtered, carcass quality was evaluated, and samples of musculus longissimus thoracis were collected to determine the proximate composition and quality of meat. Results: Bulls were characterized by the highest percentage share of the most valuable cuts in the carcass, and three-rib sections from bull carcasses had the highest lean meat content with low intramuscular fat content (0.93%). No significant differences in carcass conformation, dressing percentage or the percentage share of round in the right half-carcass were found between bulls vs. steers and heifers. Heifers and steers had higher carcass fat content than bulls, which had a positive influence on the sensory properties of beef. In comparison with the meat of bulls, the meat of steers and heifers was characterized by more desirable physical properties and sensory attributes (water-holding capacity, shear force, color lightness, aroma, juiciness, tenderness, flavor). Conclusion: Under the semi-intensive production system, heifers and steers had higher carcass fat content than bulls, which had a positive effect on the sensory properties of beef. Bulls are better suited for intensive systems, which contribute to improving the quality of their meat. The results of this study may encourage producers to breed steers and heifers for beef.

The effects of age and gender (bull vs steer) on the feeding behavior of young beef cattle fed grass silage

Natalia Puzio,Cezary Purwin,Zenon Nogalski,Ireneusz Bialobrzewski,Lukasz Tomczyk,Jacek P Michalski 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.8

Objective: The objective of this study was to determine the effects of age and gender (bull vs steer) on feeding behavior parameters in young beef cattle fed grass silage. Methods: The study was conducted on 180 young beef cattle at 7 to 18 mo of age. The experimental materials comprised 90 bulls produced by commercial crossing of Polish Holstein-Friesian cows with Charolais, Limousin and Hereford bulls (30 animals of each breed) and 90 steers of the same genotypes. The animals had ad libitum access to grass silage; the concentrate was fed separately, in feed stations. They received 28 g dry matter of concentrate per kg of metabolic body weight per day. Bunk visit data and silage intake for all experimental animals were recorded individually using the Roughage Intake Control system (5 feed bunks per 15 animals). Results: Age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle. The frequency of bunk visits and meal frequency decreased, whereas the feeding rate of silage, and the average duration and size of a single meal increased with age (p<0.01). Bunk attendance and meal frequency were higher (p<0.01) in steers than in bulls (49.1 vs 37.4 visits/d, and 8.63 vs 7.99 meals/d, respectively). Daily feeding time was longer in steers than in bulls (102.3 vs 100.3 min/d, respectively), but the feeding rate of silage was lower in steers, and their meals were smaller in size and shorter in duration (p<0.01). Daily silage dry matter intake was higher (p<0.01) in bulls than in steers (4.62 vs 4.47 kg/d, respectively). Conclusion: The results of this study indicate that age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle.

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

Sobczuk-Szul, Monika,Wronski, Marek,Wielgosz-Groth, Zofia,Mochol, Magdalena,Rzemieniewski, Arkadiusz,Nogalski, Zenon,Pogorzelska-Przybylek, Paulina,Purwin, Cezary Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.2

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${\times}$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 ($p{\leq}0.01$) and conjugated linoleic acid ($p{\leq}0.05$). There was an interaction between the slaughter season and fat type for the content of C20:4 ($p{\leq}0.01$) and C20:5 ($p{\leq}0.05$). 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.