Browsing Animal & Bioscience by Author "Black, Alistair D"
Peripheral and gastrointestinal immune systems of healthy cattle raised outdoors at pasture or indoors on a concentrate-based rationLejeune, Alexandre; Monahan, Frank J; Moloney, Aidan P; Earley, Bernadette; Black, Alistair D; Campion, Deirdre P; Englishby, Tanya; Reilly, Petrina; O'Doherty, John V.; Sweeney, Torres (Biomed Central, 2010-03-31)Background: Despite an increasing preference of consumers for beef produced from more extensive pasture-based production systems and potential human health benefits from the consumption of such beef, data regarding the health status of animals raised on pasture are limited. The objective of this study was to characterise specific aspects of the bovine peripheral and the gastrointestinal muscosal immune systems of cattle raised on an outdoor pasture system in comparison to animals raised on a conventional intensive indoor concentrate-based system. Results: A number of in vitro functional tests of immune cells suggested subtle differences between the animals on the outdoor versus indoor production systems. There was a decrease in the number of neutrophils and monocytes engaged in phagocytosis in outdoor cattle (P < 0.01 and P < 0.05, respectively) in comparison to those indoors. Following mitogen stimulation, a lower level of interferon-γ was produced in leukocytes from the outdoor animals (P < 0.05). There was evidence of a gastrointestinal nematode infection in the outdoor animals with elevated levels of serum pepsinogen (P < 0.001), a higher number of eosinophils (P < 0.05) and a higher level of interleukin-4 and stem cell factor mRNA expression (P < 0.05) in the outdoor animals in comparison to the indoor animals. Lower levels of copper and iodine were measured in the outdoor animals in comparison to indoor animals (P < 0.001). Conclusion: Despite distinctly contrasting production systems, only subtle differences were identified in the peripheral immune parameters measured between cattle raised at pasture in comparison to animals raised on a conventional intensive indoor concentrate-based production system.
Studies of Autumn calving suckler cows, bulls at pasture and winter grazingBlack, Alistair D; O’Riordan, Edward G.; Weldon, B.; French, Padraig (Teagasc, 2010-09)Most beef and dairy cows are spring calving leading to distinct seasonality of supply. Calving a proportion of the beef herd in the autumn would lead to a more uniform annual supply of cattle for slaughter and potentially increase the proportion of grazed grass in the diet of the suckler progeny. Autumn calving sucklers also facilitate the use of AI, which should enhance the product quality. This project aimed to address the technical aspects of autumn calving sucklers, which differ from those of spring calvers. The currently available international energy models were evaluated for autumn calving lactating suckler cows using the type of cow typically found in Irish suckler herds (Experiment 1). The winter accommodation of the suckler cow and calf unit and its impact on cow reproductive performance was evaluated (Experiment 2). The final part of the project evolved into component studies to determine the effect of supplementary feed on the performance of grazing bulls (Experiment 3), and the consequences of weanling cattle grazing pasture in winter as an alternative to housing them in winter (Experiments 4 to 7).