Gaļas šķirņu liellopu nobarošanas rezultātu, liemeņu kvalitātes un gaļas sastāva izvērtējums = Assessment of fattening results, carcass quality and meat composition of beef breed cattle: promocijas darbs zinātnes doktora grāda (Ph.D.) iegūšanai lauksaimniecības, meža un veterinārajās zinātnēs

The scientific work was developed from 2017 to 2021 based on three studies. The information necessary for the development of the work was obtained from the database of the Latvian Agricultural Data Centre, the Lithuanian Beef Breeders Association, and the certified slaughterhouse “Agaras”. The selection of cattle for determining the chemical composition of the meat was carried out on farms in Latvia and Lithuania in 2018 and 2019. The research for the doctoral thesis was partially implemented with the financial support of the research programme of the Latvia University of Life Sciences and Technologies “Strengthening the science capacity of Latvia University of Life Sciences and Technologies” under scientific project No. 3.2.-8/57 “Suitability of Beef Breeds and Their Crossbreeds for Fattening with Grass Forage” and the European Social Fund project No. 8.2.2.0/20/I/001 “LLU Transition to a new funding model of doctoral studies”. Work hypothesis – Aberdeen Angus, Hereford, Limousin, and Charolais cattle are suitable for fattening under Latvian conditions, ensuring the production of high-quality carcasses and meat. The aim of the thesis – to analyse the situation of the beef cattle sector in Latvia, to explain the influence of cattle breed and sex on fattening results and carcass quality, and to determine the chemical composition of the beef. Research tasks: 1. To analyse the development of the beef cattle sector based on changes in the number of cattle in Latvian herds. 2. To determine the number of cattle slaughtered in slaughterhouses in Latvia and exported live from the country, and evaluate the quality of carcasses from cattle slaughtered in Latvian slaughterhouses. 3. To analyse and explain the impact of breed and sex on cattle fattening results and carcass quality. 4. To calculate the revenue from the sales of cattle carcasses depending on the breed and sex. 5. To assess the effect of the sex and breed of cattle on meat pH. 6. To analyse the chemical composition of bull meat, focusing on unsaturated omega-6 and omega-3 fatty acids. The structure of the thesis: Chapter 1 – The literature review includes four subsections. This chapter provides an overview of the development and market situation of beef cattle breeding in Latvia. It also examines factors influencing cattle fattening and carcass quality, and compiles information on the composition, quality, and influencing factors of beef. Chapter 2 – Materials and methods includes four subsections. These subsections provide information on the methodology of the scientific work, including data sources, structuring, implementation process, and methods for mathematical data processing. Chapter 3 – The results and discussion chapter includes three subsections, each presenting the results of one study: the first study provides insight into the changes in the number of purebred and crossbred beef cattle in Latvian herds, the number of cattle slaughtered in Latvia and exported live from the country, and the quality of carcasses obtained in Latvian slaughterhouses; the second study describes the impact of breed and gender on the fattening results and carcass quality of Aberdeen Angus, Hereford, Limousin, and Charolais cattle. It evaluates the interaction of these factors and analyses the obtained fattening results and carcass quality; the third study analyses the differences in meat pH based on the gender and breed of cattle, including Aberdeen Angus, Hereford, Limousin, and Charolais bulls and heifers. It also examines the chemical composition of the longissimus dorsi muscle in bulls from three breeds (Aberdeen Angus, Hereford, Limousin). The conclusions include answers to the tasks. The paper contains 14 tables, 27 figures, 18 annexes, 246 scientific source references, 31 footnotes.