Effect of Age at First Calving on the Reproduction Parameters, Metabolic Profile, and Fatty Acid Composition of Polish Holstein Friesian (PHF) and Crossbreds PHF × Swedish Red (SRB) Cattle.

Background: The high dairy production of Polish Holstein Friesian (PHF) cows determines high energy requirements in the early stages of lactation. Unfortunately, it is very often difficult to meet this demand through feedstuffs; therefore, homeostasis may be disturbed and metabolic diseases may occur, causing a majority of cows' health problems. Breeders are, therefore, looking for alternatives to the PHF breed using crossbreeding.

The quality and technological parameters of milk obtained from dairy cows with subclinical mastitis.

Mastitis is one of the most common diseases in dairy cattle. It significantly reduces milk quality and yield, thus incurring economic losses for farmers. This study investigates the impact of various bacterial pathogens on the somatic cell count, milk composition, and technological properties of milk samples from 302 clinically healthy Polish Holstein-Friesian cows kept under intensive rearing conditions.

Genotype-Dependent Variations in Oxidative Stress Markers and Bioactive Proteins in Hereford Bulls: Associations with , , and Genes.

The objective of this study is to assess the influence of genetic polymorphisms in , , and on the oxidative stress biomarkers and bioactive protein levels in Hereford bulls. A total of sixty-eight bulls were analyzed at 22 months of age to assess growth metrics and carcass quality, with a focus on polymorphisms in these genes. The key markers of oxidative stress, including malondialdehyde (MDA), and the activities of antioxidant enzymes such as glutathione reductase (GluRed), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were measured, alongside bioactive compounds like taurine, carnosine, and anserine.

Genetic Markers Related to Meat Quality Properties in Fattened HF and HF x Charolaise Steers.

This study involved 45 Holstein and 60 Holstein-Charolaise steers, tailored with specific diets according to breed and rearing systems. DNA genotyping was conducted for DGAT1, LEP, SCD1, SREBF1, and TG genes to investigate their impact on carcass conformation traits, beef quality traits, and sensory quality traits. The results showed associations between the genetic variants and the analyzed traits.

Relationship between Beef Quality and Bull Breed.

The beef industry in Poland heavily relies on the Polish Holstein-Friesian (PHF) breed, known for its primary use in dairy production, but which also contributes significantly to the beef supply. In contrast, the Limousine (LM), Hereford (HH), and Charolaise (CH) breeds have gained popularity due to their ideal specialized characteristics for beef production. As PHF continues to dominate the beef market, a thorough comparison of its beef quality and nutritional attributes with the three most popular beef breeds in Poland is essential.