Photo AI
Give scientific explanations for any four of the following: (a) The reduced incidence of liver fluke (Fasciola hepatica) infestation in cattle grazed on well-drained pasture - Leaving Cert Agricultural Science - Question 9 - 2016
Question 9
Give scientific explanations for any four of the following: (a) The reduced incidence of liver fluke (Fasciola hepatica) infestation in cattle grazed on well-draine... show full transcript
Worked Solution & Example Answer:Give scientific explanations for any four of the following: (a) The reduced incidence of liver fluke (Fasciola hepatica) infestation in cattle grazed on well-drained pasture - Leaving Cert Agricultural Science - Question 9 - 2016
Step 1
(a) The reduced incidence of liver fluke (Fasciola hepatica) infestation in cattle grazed on well-drained pasture.
Answer
The reduced incidence of liver fluke infestation in cattle is largely due to the environmental conditions that affect the snail host, which is necessary for the lifecycle of Fasciola hepatica. Well-drained pastures reduce the presence of standing water, which is essential for the survival of the larval stages of the fluke. In such dry conditions, the snails (intermediate hosts) are less likely to thrive, thus diminishing the lifecycle of the parasite and lowering the risk of infection in the cattle.
Step 2
(b) The movement of water from the soil through a plant and into the atmosphere.
Answer
Water movement in plants occurs via a process called transpiration, which involves several steps. Initially, water is absorbed by the roots through root hairs via osmosis. It then travels through the root xylem and into the stems and leaves. The water subsequently evaporates from the stomata in the leaves, creating a negative pressure that pulls more water up from the roots through capillary action. This process not only transports vital nutrients but also helps maintain cell turgor and temperature regulation in the plant.
Step 3
(c) The use of cross-breed sows in pig production.
Answer
Cross-breeding sows involves mating two different breeds to combine their desirable traits. This can result in offspring that exhibit hybrid vigor, meaning they can have enhanced growth rates, better feed conversion ratios (FCR), superior meat quality, and improved reproductive performance. By leveraging the genetic strengths of each breed, producers can enhance productivity while promoting resilience and health in the pigs.
Step 4
(d) The use of acid as an additive in silage making.
Answer
The addition of acids such as sulphuric or formic acid during the silage-making process is critical for controlling pH levels. These acids inhibit undesirable bacterial activity that can lead to spoilage. By lowering the pH, they create an environment that favors lactic acid fermentation, ensuring that the silage preserves its nutritional quality. This preservation is crucial for maintaining feed quality during the winter months when forage may be scarce.
Step 5
(e) An increase in the yield of crops exposed to higher levels of carbon dioxide in a greenhouse.
Answer
Higher levels of carbon dioxide (CO₂) enhance the photosynthetic capacity of plants. During photosynthesis, CO₂ is absorbed by the leaves and converted into glucose, which is vital for energy and growth. With elevated CO₂, the rate of photosynthesis increases, leading to more glucose production. This facilitates greater biomass accumulation and, consequently, an increase in crop yield. Additionally, more CO₂ can enhance water use efficiency, allowing plants to thrive under greenhouse conditions.