NUTRITION AND MANAGEMENT STRATEGIES TO IMPROVE HEALTH AND MEAT QUALITY OF INTENSIVELY REARED RUMINANTS
Tesi di Dottorato
Data di Pubblicazione:
2015
Citazione:
NUTRITION AND MANAGEMENT STRATEGIES TO IMPROVE HEALTH AND MEAT QUALITY OF INTENSIVELY REARED RUMINANTS / G. Baldi ; tutor: V. Dell'Orto ; coordinator: G. Savoini. DIPARTIMENTO DI SCIENZE VETERINARIE PER LA SALUTE, LA PRODUZIONE ANIMALE E LA SICUREZZA ALIMENTARE, 2015 Dec 18. 28. ciclo, Anno Accademico 2015. [10.13130/g-baldi_phd2015-12-18].
Abstract:
Nowadays meat quality perception is multifactorial and, especially for red meat, consumers are becoming more and more critics about sensory traits and concerned about psychological and ethical aspects, such as sustainability, animal welfare, antibiotics utilization, safety and healthiness. Address to these topics is fundamental for red meat industry, in order to counteract the decreasing consumption in western countries and to improve production efficiency to fulfill the growing demand from developing countries.
Improving all the aspects related to perceived quality will lead to meet consumer satisfaction, with positive impact on demand, and to increase production efficiency and profitability. The following trials aimed to evaluate specific dietary supplements and on farm and post farm strategies to improve animal health, strictly connected with sustainability, animal welfare and production efficiency, and meat appearance and eating quality.
8.1. Trial 1
Bovine respiratory disease (BRD) represents a concern for veal industry, as it causes economic losses, reduces animal welfare and increases antibiotics utilization. A field study to evaluate the effects of multivalent vaccination on veal calves’ health and performance was carried out. 944 healthy calves were randomly allotted into two separate barns. One group was vaccinated 7 days after arrival with quadrivalent vaccine against IBR, PI3, BRSV and BVDV Type 1 viruses plus booster administration 21 days apart (VAC; 675 calves), while the second group was not treated (CON; 269 calves). Vaccination did not affect overall mortality (P=0.75) and mortality due to BRD (P=0.28), while it reduced BRD morbidity (P=0.009). VAC group showed better average daily gain (ADG; P=0.03) and carcass weight (P<0.001). Vaccination delayed the peak of BRD by nearly two weeks (P<0.001) and represented a protective factor against BRD (OR 0.55; P=0.001). BRD increased mortality (P=0.01), lowered ADG (P<0.001) and carcass weight (P<0.001), increased the amount of discounted carcasses (P<0.001). Lung lesions and pleuritis and/or consolidations increased with BRD (P=<0.001) but were unaffected by vaccination (P=0.40 and P=0.43 respectively). In conclusion, BRD impaired veal calves’ health, growth and carcass value and vaccination reduced BRD morbidity, thus improving carcass value.
8.2. Trial 2
Selenium (Se) is involved in several biological functions and its supplementation is necessary for farm animals. Se can be provided in organic or inorganic forms, the former characterized by a higher bioavailability. Despite organic supplementation generally increased the meat Se, inconsistencies in the effects on meat quality have been reported and only one short–term supplementation study has been performed. The study aimed to compare the effects of switching the Se source in the last 60 days of fattening on growth performance, beef quality and Se content. Charolaise beef heifers supplemented since the beginning of the fattening period with sodium selenite (162 heads; 517±61 days of age) were divided into two groups, fed the same diet, in which Se (0.2 mg Se/kg DM of feed) was provided as sodium selenite (SS; 82 heads, 450.36±33.69 kg BW) or selenium-enriched yeast (Se-Y; 80 heads, 454.60±41.70 kg BW). Live weight was measured at the beginning and at the end of the trial and meat samples were collected from 30 homogeneous carcasses/group 48 hours post mortem to evaluate centesimal composition, Se content, shear force and cooking loss. Colour, pH, water holding capacity and appearance were evaluated daily for 8 consecutive days of aerobic storage. The Se source did not affect growth performance, meat centesimal composition, thawing loss, cooking and drip loss and pH during 8 days of aerobic stora
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
G. Baldi
Link alla scheda completa:
Link al Full Text: