Experiments evaluated the effect of glyphosate rate and Anoda cristata density, on crop and weed biomass and weed seed production in wide (70 cm) and narrow rows (35 cm) glyphosate‐resistant soyabean (Glycine max). Soyabean density was higher at 35 cm row spacing as an increase in planting rate in narrow‐row soyabean is recommended for producers in Argentina. Soyabean biomass at growth stage V4 (four nodes on the main stem with fully developed leaves beginning with the unifoliate leaves) was higher when grown on narrow than in wide‐rows but was not affected by the presence of A. cristata. At growth stage R5 (seed initiation – seed 3 mm long in a pod at one of the four uppermost nodes on the main stem, with a fully developed leaf and full canopy development), crop biomass was greater in narrow rows compared with wide rows with 12 plants m?2 of A. cristata. In narrow‐row soyabean, a single application of a reduced rate of glyphosate maintained soyabean biomass at R5 and provided excellent weed control regardless of weed density. In wide‐row soyabean control was reduced at the high weed density. Regardless of row spacing, A. cristata biomass and seed production were severely reduced by half of the recommended dose rate of glyphosate but the relationship between biomass and seed production was not altered. Glyphosate rates as low as 67.5 g a.e. ha?1 in narrow rows or 540 g a.e. ha?1 in wide rows provided excellent control of A. cristata. To minimize glyphosate use, planting narrow‐row soyabean are effective where A. cristata density is low. 相似文献
AIMS: To determine the effect of providing water within the area grazed by dairy cows on milk yield and quality, compared to requiring cows to walk to a distant water trough, on a dairy farm in the Pampa region of Argentina during summer.
METHODS: Holstein dairy cows were allocated to two herds with similar parity, days in milk and milk production. They were grazed in one paddock that was divided in two, with a fixed water trough at one end. Cows were moved twice daily to grazing plots within the paddock. Control cows (n=66) could only access water from the fixed trough, whereas supplemented cows (n=67) also received water from a mobile trough within the grazing plot. Milk production of each cow, and water consumption of the two herds were measured daily over 62 days. Milk composition for each herd was determined weekly from Days 18 to 60 of the study, and grazing behaviour was observed between 08:00 and 16:00 hours on Days 11–15, 19–22 and 39–43.
RESULTS: Over the 62 days of the study, supplemented cows produced 1.39 (SE 0.11) L/cow/day more milk than Control cows (p=0.027). Estimated mean daily water intake was 50.4 (SE 2.1) L/cow/day for supplemented cows and 58.2 (SE 2.7) L/cow/day for Control cows (p=0.004). Percentage total solids in milk was higher for supplemented (12.5 (SE 0.06)%) than Control (12.4 (SE 0.04)%) cows (p=0.047). During the periods of behavioural observation, a higher percentage of cows in the water supplemented than the Control herd were observed in the grazing area (p=0.012).
CONCLUSIONS AND CLINICAL RELEVANCE: This preliminary study demonstrated that provision of water to dairy cows within the grazing plot was beneficial for milk production and composition, and may be associated with longer periods spent within the grazing area, during hot weather in the Pampa region of Argentina. 相似文献
1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.
2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.
3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.
4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.
5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile. 相似文献
The aim of this study was to investigate the effect of dietary supplementation with the docosahexaenoic acid (DHA )‐rich microalgae, Aurantiochytrium limacinum (AURA ), on a variety of health and productivity parameters in lactating cows. Twenty‐four cows were blocked by parity and number of days in milk and then randomly assigned to a control (CON ; n = 12) group with no algal supplementation, or a treatment group (AURA ; n = 12) provided with 100 g AURA cow?1 day?1 or 16 g DHA cow?1 day?1. A variety of health and productivity measurements were taken, and results indicated that supplementation had no negative effects on animal health in terms of somatic cell count, haematological and biochemical blood parameters, while body condition was marginally improved by algal supplementation. No differences were found for the various production parameters measured; however, a tendency towards increased milk production was observed for the AURA group during the final stage of the study (+4.5 kg cow?1 day?1, day 78–84). The fatty acid profile of milk was improved by supplementation, with significantly lower saturated fatty acids, significantly higher omega‐3 fatty acids and an improved omega‐3/omega‐6 ratio observed when compared to the control group. The amount of DHA in the milk of cows provided 105 g AURA head?1 day?1 was 4.7 mg/100 g milk with a peak transfer efficiency from feed to milk at day 49 of 8.3%. These results indicate that supplementation with 105 g AURA head?1 day?1 resulted in the successful enrichment of milk with DHA without negatively impacting the health or productivity of the animals. 相似文献
Efficient red deer supplementary feeding depends on estimations of the nutritive value of offered feeds, frequently estimated with the use of equations derived from domestic ruminants. The aim of this study was to compare the 24‐hour in vitro true dry matter degradability (ivTD24), in vitro gas production (GP) kinetic parameters, GP in 24 hr of incubation (GAS24) and short‐chain fatty acid (SCFA) and microbial biomass (MBS) produced after 24‐hour incubation of feeds in inoculum prepared from sheep and red deer rumen fluid. Eleven feeds, frequently consumed by red deer in Slovenia, which occur either naturally (two fresh grasses, chestnut fruits and common and sessile oak acorns) or are fed as winter supplemental feeds (two grass hays, two grass silages, apple pomace, fresh sugar beetroot), were investigated. The in vitro GP kinetic parameters, GAS24 and ivTD24, did not differ between animal species. Amounts of SCFAs were greater (p < 0.05) when feeds were incubated in sheep inoculum, while molar proportions of acetic and propionic acids did not differ. Molar proportions of butyric acid produced during incubation of high fibre feeds did not differ between animal species, but were higher (p < 0.05) when feeds high in starch or sugar were incubated in red deer inoculum. Greater production of SCFA by sheep rumen microbes suggests better coverage of host animal with energy precursors, while greater production of MBS by red deer rumen microbes suggests better coverage of host animal with protein. Results also suggest that rumens of sheep and red deer are inhabited by different microbial communities, which did not affect the extent of in vitro GP and degradation of feeds used in the present experiment. However, the possibility exists that the divergent nutrient use could be a consequence of different priming by different feeds of the donor animal diets. 相似文献
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