Subject: Describe modification of livestock reproduction or plant propagation to improve productivity (90453)

Transcription

1 Assessment Schedule 2011 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 1 of 8 Subject: Describe modification of livestock reproduction or plant propagation to improve productivity (90453) vidence Statement SCTION A: AGRICULTURAL SCINC ON Scanning Techniques Describes equipment associated with a scanning technique. xplains how equipment is used to provide accurate readings. Scanning of dairy cows Cows are held in a confined space and the vet / technician uses a long, flexible hose containing the probe on the end that is inserted into the rectum. The transponder on the probe sends an image to a monitor that is interpreted by the operator. Lubricating fluid is applied to the probe. Scanning of sheep The scanning probe is applied between the back legs and forward of the udder, so that there is minimal distance and tissue between probe and foetus, thereby maximising the electronic response to the probe. Water spray from the probe improves skin contact, and maintaining dark conditions allows for increased accuracy when reading images on the monitor screen. Describes the stage of pregnancy. Scanning is usually performed during the earlier stages of pregnancy 6 to 8 weeks into the pregnancy. xplains the scanning of dairy cows OR the benefits of scanning. Scanning allows farmers to determine which cows are dry and therefore should be culled to avoid them eating valuable feed supplies at a time when pasture growth is limited. Knowing the stage of foetal development will allow farmers to programme the calving season to maximise survival rates and make best use of labour. They may consider other management practices such as inductions or culling, depending on the result of individual scans, in order that pregnant cows have a relatively tight calving pattern to ensure that calving coincides with the flush of pasture growth and higher milk production. All these aspects have financial implications. Justifies the increased use of scanning of dairy cows. Scanning gives advanced warning of which cows will calve or be late calving, and therefore allows time for the farmer to consider options. A dry cow is not an economic option unless it is due to unusual circumstances, eg good quality cow, but faulty insemination practice. The driving force will be for all cows to calve within one month in order that lactation coincides with maximum pasture growth and disruptions to milk pecking orders are minimal. Scanning usually results from this. In dry seasons with limited feed supplies, a choice often has to be made between a late calving cow being culled or being induced. While it is argued that inductions are inhumane, farmers will argue that it is better for the cow than being sent to the works for slaughter. Depending on the attitude of the

2 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 2 of 8 farmer, either the slaughter rates increase or the induction rates increase during drought conditions.

3 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 3 of 8 TWO we and Ram Selection Describes actions wool production Record the ear tag number, then make notes on overall body size, wool coverage, eg around head, down legs. Wool quality could be observed by parting fleece at strategic points, eg mid-side, and recording details on micron, colour, and evenness of crimp. xplains why visual assessment is unreliable. The production potential for all characteristics is determined by genetic factors. Whether this potential is reached is determined by environmental factors such as nutrition, disease, climate, etc. Unfortunately the genetic makeup of the animal cannot be seen, and basing selection on visual appearance could result in environmental factors rather than the genotype dominating selection. A heavy ewe may be selected over a lighter-weight ewe, but the lightweight ewe could be that way because she has reared triplets, whereas the heavy ewe was dry. Describes important factors: days from birth to killing, to achieve grading PX eye muscle area. xplains why factors are important. Days to kill will reflect, to some extent, the ability to impart growth rates and produce a carcass of low fat cover. A quick turnover means more feed available for other uses. ye muscle area impacts on the cut size that is available for processors, and the variety of different cuts that can be produced by processors for consumer use. A higher eye muscle area gives an ability to satisfy a range of end uses. Justifies the use of ram 65/06. On the basis of all information provided, this ram has the best data for all the important attributes and is on par with the reliability of the data provided. MA data relates to the highvalue meat cuts, while the fast turnover does have a real economic advantage in the summer period and when producing early lambs with price premiums. While the dressing percentage is similar to other breeds, it represents a very small amount of boned out cuts. The reliability of the data is relatively high, because of a higher number of progeny (lambs) tested. The other rams may have a higher value for one item, but the item has a lesser impact on commercial value.

4 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 4 of 8 THR Use of CIDRs Describes the design and method of use. CIDRs are T-shaped silicon elastomer devices with springback wings and a plastic draw tag. They are inserted into the vagina with a simple applicator. xplains how CIDRs work. Once inside the vagina, they slowly release progesterone through the vaginal wall. Sufficient progesterone in the bloodstream prevents cycling. On removal, the level of progesterone falls, stimulating visible heat 2 4 days after withdrawal. Describes the timing of use of CIDRs. xplains importance of use. Comparison of importance of CIDRs for two techniques. embryo transfer At the beginning of the process CIDRs are placed in both the donor and recipient animals. embryo transfer Successful transplantation of embryos depends on close synchronisation of the oestrous cycles of donor and recipient animals, because the growth of the embryo is determined by its requirements being met by the uterine secretions of food. The production and chemical nature of this food changes. If timing is wrong, implantation will not be successful. The use of CIDRs for embryo transfer is essential to the success of a relatively expensive technique. Provided that CIDRs are used correctly, a 90% conception rate can be expected, whereas if the oestrous cycles are out of phase by one day the conception rate falls to about 50%. This is a significant difference and represents a high cost for the embryos that do implant successfully. In the case of artificial insemination, the use of CIDRs is not critical to the overall success of this technique, provided that quality semen used by skilled technicians is used on cows that have been accurately assessed as being on heat. The use of CIDRs is mainly a timing issue that allows for easier management at the time of insemination, and later at calving. There are many farmers who use AI but do not use CIDRs. No technician would contemplate an embryo transfer without the use of CIDRs. Judgement Statement Achievement Achievement with Merit Achievement with xcellence

5 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 5 of 8 SCTION B: HORTICULTURAL SCINC ON Sexual Propagation Seed Treatment Describes the effect sandpaper has on the hard seed. The sandpaper scarifies the seed, breaking the hard coat and allowing water to enter. This makes the hard seed coat permeable to water. xplains how the action of the sandpaper assists in breaking the dormancy of the seed. The hard seed coat inhibits germination by preventing the entrance of water into the seed. The sandpaper weakens the seed coat, allowing water to enter and start chemical processes that encourage germination. (c) Describes how the treated seeds affect crop establishment. ncourages more even seed germination and therefore more even growing, which is more useful when establishing a crop. Seeding rates can be at a lower rate. Plants are ready for transplanting at the same time. xplains the effect of treated seeds on crop production. Seedlings produced are likely to be of similar size and can be managed in the same way before selling when of a similar standard. Few seeds need to be sown, with the knowledge that all seeds could germinate given correct conditions. Having a known time frame for reaching maturity allows the farmer to plan the establishment of plants, so that they are ready to be transplanted when needed. Therefore they are able to plan ahead. xplains the financial outcomes for the farmer of using treated seeds. The grower would have a much greater financial outlay for the treated seeds, but would get a better guarantee that a crop will be produced that is of uniformly higher yield and quality. When producing crops for sale, a higher-yielding crop will produce a higher return than a lower-yielding crop of the same quality. The costs of production are similar for both a high- and low-yielding crop. ven seed germination and growth leads to easy planning and less plant wastage. Must link breaking of dormancy to higher returns for farmer.

6 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 6 of 8 TWO Scion and Rootstock Selection Describes characteristics (TWO) of a rootstock suitable for grafting with a scion. xplains why a knowledge of plant tissues is essential for a successful graft. Select healthy, disease-free rootstock that shows good plant vigour. Select material in early spring when buds are beginning to swell, but before active growth. Healthy, disease-free plant tissue ensures there is no transmission of diseases, particularly those caused by viruses. Cambium layer is an actively growing group of cells between the xylem and phloem. They are responsible for secondary growth. The cambium layers must line up to be able to fuse and grow together. This increases the possibility of a successful take, leading to an increased number of mature plants being produced. Describes management practices affected by the use of dwarfing rootstock. xplains the impact of management practices on production. xplains how the use of dwarf rootstock results in higher returns and greater income. xamples: pruning training thinning spraying harvesting Harvesting lower trees reduce need for ladders to pick fruit, so harvesting is quicker and less costly for the grower. Spraying less equipment is needed to reach the growing areas of the plants, so there is less cost involved and hence higher returns to the grower. Thinning excess fruit can be removed by hand, which is less costly to the grower. Smaller canopy allows better light penetration to the fruit and leaves, increasing photosynthesis and speeding up ripening. Harvesting or strip-picking of the fruit will be easier and quicker, as most of it can be picked from the ground. The pickers will not be required to spend much time up on ladders, and accuracy when picking will increase. This reduces the risk of bruising. Additionally, the lack of tree height will improve apple colour, as sunlight will be able to get through the tree to the lower fruit. The resulting higher-quality fruit will have more value. Spraying is easier to carry out from ground level, and coverage is easier. Ladders are not needed and penetration of the canopy is easier. This reduces the risk of mis-spraying and damage to fruit. More even coverage of spray leads to a higher quality of fruit and therefore a higher return. Answer may count towards.

7 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 7 of 8 THR Asexual Propagation Tissue Culture Describes how the chosen technique is used in propagation by tissue culture. stablishment and sterilisation quipment and materials to be used for tissue culture preparation should be sterilised, using bleach or alcohol solution. These include: petri dishes knives and forceps culturing media gloves, masks, aprons, goggles and other protective gear. Growth regulators: Different auxins and cytokinins are added to growth media to promote growth, ensuring the successful development of plantlets. Acclimatisation Acclimatisation is the process by which species grown in vitro become used to different conditions in order to ensure that a sufficient number of plants survive and grow vigorously when transferred to soil. xplains how the chosen technique ensures success when using tissue culture as a method of propagation. stablishment and sterilisation The proper sterilisation of samples and the instruments to be used for tissue culture preparation is important, particularly because contamination from dust, dirt, fungi and microbes can ruin the samples and affect the outcome. Materials that will touch the tissue samples must be sterilised during the preparation process. The tissue samples must also be rinsed following recommended procedures, to ensure that they are free from contamination. A clean area will also limit the number of contaminants that might find their way into the tissue culture. Acclimatisation A substantial number of micropropagated plants do not survive transfer from in vitro conditions to a greenhouse or field environment. Acclimatisation is important to ensure that quality plants can be produced in a commercial setting. (c) Describes how growth regulators affect production of plantlets. Plantlets grown with growth regulators introduced to growing media show significantly more successful growth into plantlets than those grown on untreated media. xplains how growth regulators would impact on establishment and acclimatisation. Growth regulators Auxin for enhancement of callus growth and root initiation in vitro. Cytokinin is for stimulation of shoot production. Acclimatisation A larger number of roots and shoots will be produced. Because of the increased root surface area, and the ability to absorb water and nutrients, the supply of these important Justifies the use of growth regulators as the method that produces a higher financial return. By applying the appropriate growth regulator in the concentration required in the growth medium, a larger number of roots and shoots will be produced. Because of the increased ability of the roots to absorb water and nutrients, and better anchorage in the growing media, along with increased potential for photosynthesis from larger shoots, larger and

8 NCA Level 2 Agricultural and Horticultural Science (90453) 2011 page 8 of 8 growth factors is increased, and provided that temperature conditions are appropriate, the growth rates of the plantlets are enhanced. stronger plants will be produced, and there will be a reduction in the time required for plants to reach market suitability. A greater survival rate will result, especially if the plants are transplanted, therefore ensuring a larger number of plants for sale, thus increasing financial returns. This reduced time required to produce plants means that more can be produced in a given time period, and at different times of the year, thus increasing financial returns. Judgement Statement Achievement Achievement with Merit Achievement with xcellence