STRATEGIES FOR THE PREVENTION AND REDUCTION OF THE MAIN HEALTH PROBLEMS IN THE BEEF CATTLE REARING

Italian beef cattle\u2019s rearing is mainly based on fattening imported young animal from abroad. For animals, as occur also in the humans, the adaptation to new environment and social conditions gives rise to stress condition; this situation could drive the subject to severe physiologic and psychological reactions and compromise the health. To meet the consumer needs, at the present time farmer target is to obtain high quality meat as quick as possible in order to reduce the rearing cost and to improve the animal welfare. Therefore, nutritional level and sanitary condition must be the best to stimulate the greater growth than possible. Considering that, the italian typical beef cattle rearing needs to be based on diets characterized by high energy concentrations and on sanitary programs. The correct management of vaccination, antibiotic treatment and nutrition are important both in the fattening period and in the adaptation phase. The objective of the present doctoral study was to evaluate the incidence and the severity of the health problems in the italian beef cattle rearing focusing the attention on Bovine Respiratory Disease and parasitosis. With this aim, an important part of the study was dedicated to evaluate the effectiveness of drugs administration to reduce the incidence and severity of BRD and to understand how specifics plant extracts could reduce the parasitic infestation. As mentioned, the adaptation phase is the first important critical point of the entire breeding process and any problem that occurs during this phase can compromise the entire rearing period. BRD, nutritional diseases and parasitosis cause a decrease in productive performances, an increase in pharmacological costs, technical and veterinary assistance, convenience culling, mortality, and consequently the length of breeding process and financial liabilities. In the first study it has been enquired the incidence and the importance of the more important sanitary problems of the adaptation phase in imported beef cattle related with some animal\u2019s parameters. The enquired parameters were body weight, weight loss, incidence of pulmonary disease, incidence of locomotion disease due to traumatic and nutritional causes, incidence of animals moved in sick-bay pens due to pulmonary or locomotion diseases and finally mortality and the cause of it. To analyze the parameters listed above, the weight of the animals was divided in four classes ( 451 Kg), the weight loss was divided in four classes ( 7%), the breeds was charolaise, limousine and crossbreed, and finally it has been considered the two sex. The data collected showed that pulmonary disease is inversely proportional to the body weight while the locomotion system diseases are directly proportional to that. Subjects with a low weight loss (< 2%) had a high morbidity of pulmonary disease. Female have a morbidity of the pulmonary disease higher than the male subject, primarily because the female have a body weight lower than male and there are evidence that the body weight is directly related with the weight loss and the incidence of the problems. Conversely the males are more affected by locomotion disease, probably because those subject are more competitive than the female. Limousine breed is more affected by pulmonary disease than the others, but it\u2019s also to be considered that those animals arrive from France with a body weight lower than the other imported breeds. Charolaise breed manifested high rates of locomotion disease, both traumatic and nutritional, due to the higher body weight and the higher ruminal capacity that induce to speed up the adaptation program. After the evaluation of the incidence of the main disease and the factors related, a series of subtrials were conducted in feedlots Italy to investigate the efficacy of a long acting and slow release antibiotic (gamithromycin) in the prevention and treatment of bovine respiratory disease (BRD) in newly arrived cattle. Three studies were conducted on its preventive efficacy when compared to either an untreated control, a long-acting oxytetracycline formulation or tulathromycin. The therapeutic responses to tulathromycin and gamithromycin were also compared in the therapeutic study. Preventive treatment with gamithromycin significantly reduced the morbidity due to BRD by 86%, 86% and 35% compared to the untreated control group, the oxytetracycline group and the tulathromycin group respectively. In the therapeutic trial, the number of animals that required re-treatment during the 14 days following the initial medication was significantly reduced in the gamithromycin group, compared to the positive control group. These results suggest that the dual therapeutic and preventive action of gamithromycin provides a valuable addition to the veterinarians\u2019 armamentarium for the medical management of BRD. Other than BRD, parasitic infestation is considered one of the main problems related to an increase in morbidity and bad growing performance. Cattle usually do not show clinical signs of coccidiosis unless stressed by weaning, weather, shipping or other diseases. In any case the disease can compromise the animal homeostasis and nutritional up-take worsening the weight gain. Several natural substances have capability to improve physiological and health bred animal status and some of them have anti parasite properties. The trial was managed to verify the effects of some different commercial plant extracts on growth performance and coccidia infestation in 235 newly received Charolaise beef cattle, imported from France, during the adaptation period. This trial was divided in four subtrials to test four different plant extracts or mix of them (Subtrial 1: Calendula officinalis, Castanea sativa, Plantago major, Silybum marianum, Trigonella foenum-graecum; Subtrial 2: Castanea sativa, Vitis vinifera, Citrus spp, yucca shidigera; Subtrial 3 and 4: Origanum vulgare). Plant extract mix administered in the first subtrial showed to increase growth performance, reducing damages inducted by Eimeria coccidia acting as anticoccidial. In fact both number of animals infested and number of oocysts in feces were strongly decreased. The plant extract mix used in the second subtrial showed to decrease infested animals, but the same animals emitted with the feces a greater number of oocysts, denoting higher infestation and probably greater damages. Growing performances didn\u2019t show any difference. The administration of Origanum vulgare didn\u2019t show any difference, denoting no effects on coccidia. In conclusion, the present doctoral study showed that, for a correct management of the adaptation phase, but even of the entire rearing period, it should necessary to consider some of newly received cattle\u2019s characteristics like weight at the arrival, sex and breed because are often connected with an increase of morbidity. Furthermore, the study brings out the fact that it\u2019s also very important to choose the most appropriate protocol of vaccination and antibiotic treatment to reduce the incidence of infectious diseases and also to adopt specific nutritional strategies to promote a quickly reestablishment of the normal ruminal conditions after transport and to prevent coccidiosis