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Full-Text Articles in Life Sciences
Application Of Simulation Modelling In Broiler Integration: Is It A Necessary Nutritional Tool?, Peter Chrystal
Application Of Simulation Modelling In Broiler Integration: Is It A Necessary Nutritional Tool?, Peter Chrystal
Proceedings of the Arkansas Nutrition Conference
Modelling techniques have been used in many industries globally to illustrate to others an understanding of the way processes work. Also, engineers and scientists employ models to predict the consequences of various courses of action. Simple pictorial models, such as the diagram of the chicken digestive system, are useful in education and may be more suitable than a photograph for the purposes of explaining how the animal converts ingested feed into components that can be assimilated, leaving residue that is excreted. Complex, predictive models seek to quantify a specified outcome based on defined inputs. Many attempts have been made over …
A Dynamic Approach To Feed Formulation, Rob Gous
A Dynamic Approach To Feed Formulation, Rob Gous
Proceedings of the Arkansas Nutrition Conference
The objective of this paper is to demonstrate that the opportunity cost of using fixed tables of nutrient requirements when formulating feeds for broilers can be considerable, and that nutritionists should consider a more dynamic approach to defining the lower bounds of amino acids in particular, in line with the objective of the business, which is to maximise profit. In order to do this, it is necessary to consider the potential growth rate of the broiler, the cost of feed and amount of feed consumed, and the income generated from the sale of product.
Effects Of An Injectable Zinc Solution At Weaning As An Alternative Castration Method In Beef Cattle, Reagan Nicole Cauble
Effects Of An Injectable Zinc Solution At Weaning As An Alternative Castration Method In Beef Cattle, Reagan Nicole Cauble
Graduate Theses and Dissertations
Two experiments were conducted to investigate a 1 mL intratesticular zinc (100 mg Zn) injection administered into each testicle at weaning (Z) and its effects on growth, health, behavior and testosterone. In the first experiment, beef bulls were assigned randomly to treatment at birth: 1) surgically castrated at birth (S; n = 37) or 2) Z (n = 37). Testicular thickness differed by day (P < 0.01) for Z. Testosterone concentrations were greater in Z by d 77 and remained so through d 280 (P = 0.02) compared to S. Zinc injected calves were heavier at the trail’s conclusion (P ≤ 0.04), had greater ADG overall (P < 0.01), heavier hot carcass weight (P = 0.01), and greater lean muscle area (P = 0.01) compared to S; but a lower marbling score (P < 0.01). Yield Grade, dressed carcass yield and fat thickness were similar (P ≥ 0.14). Zinc injected calves had greater haptoglobin (Hp) concentrations (P < 0.01). Zinc injected calves had greater concentrations of white blood cells on d 1 and 2 and greater concentrations and proportions of neutrophils on d 1, 2 and 3 (P < 0.01). Conversely, S had a greater percentage of lymphocytes on d 1, 2 and 3 and a lower ratio of neutrophils to lymphocytes during that same time (P < 0.01). Zinc injected calves spent more time on their side or sternum on d 1 and more time on their side on d 2 while S spend more time standing during that time (P < 0.01). During d 3, 4, 5, and 6, Z stood more while S laid on their sternum (P < 0.01). In trail 2, beef bulls were allocated randomly to treatment one week post weaning: 1) banded (B; n = 42) or 2) Z (n = 39). Body weights were similar (P ≥ 0.39) but ADG improved for Z compared to B (P = 0.05). Testosterone concentrations were greater in Z compared to B (P ≤ 0.02). Testicular width in Z differed by d (P < 0.01). Zinc castrated calves spent more time on their side compared to B one day post castration (P = 0.03) until d 3 and 4 where B spent more time on their side (P ≤ 0.02). Banded calves stood more the first two days (P ≤ 0.01). On days 3, 4, 5, and 6, Z stood more (P ≤ 0.01) while B were on their sternum (P ≤ 0.03). Banded calves had lower Hp concentrations compared to Z (P ≤ 0.01). Total white blood cell concentrations, proportions and concentrations of neutrophils, and proportion of lymphocytes were greater in Z compared to B on d 1, 2, and 3 (P ≤ 0.01). There was no interaction between treatments over time for IL1β, IL6, and TNFα expression (P ≥ 0.83). The findings in both studies indicate that intratesticular Zn injections at weaning can improve growth performance and some carcass attributes but produce a heightened inflammatory and immune response and cause discomfort. Injecting zinc, as formulated and administered in these trails, does not result in complete castration of beef calves at this age and therefore cannot be considered a true castration alternative.