酵母铬与L-肉碱对蛋鸡生产性能及脂质代谢的影响

选用21周龄海兰褐壳蛋鸡288只,随机分为9组,每组32只,采用3×3(铬×L-肉碱)2因子3水平有重复交叉试验设计,预试2周后,在玉米-豆粕型日粮的基础上添加不同水平的酵母铬(以铬计:0、400、600μg/kg)与L-肉碱(0、50、100mg/kg),以饲喂基础日粮组为对照组,用以研究二者对蛋鸡生产性能及脂质代谢的影响,并初步探讨二者的互作效应,试验期7周。结果表明:600μg/kg铬或100mg/kgL-肉碱对脂质代谢多数指标效果显著(P<0.05或0.01);二者同时添加对蛋黄胆固醇、肝脏甘油三酯及腹脂率等均产生显著互作效应(P=0.0003～0.0500),且400μg/kg铬和100mg/kgL-肉碱混合添加对降低蛋黄胆固醇比其它各组均表现出优势,400μg/kg铬和50mg/kgL-肉碱混合添加对降低腹脂率比其它各组均表现出优势。铬或(与)L-肉碱在降低蛋鸡肝脂、腹脂及蛋黄胆固醇的同时并未影响蛋鸡的生产性能。     

Anoda cristata control with glyphosate in narrow- and wide-row soyabean

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.     

植物育种的物理学方法

介绍了草原生态恢复中选育优良牧草种子的一些物理学方法,包括电场、磁场、物理辐射、激光、离子束和交变应力等在植物的生物学效应、诱变育种和转基因技术中的应用.     

以催乳素受体基因作为撒坝猪部分生产性能候选基因的研究

此文运用PCR-RFLP技术检测催乳素受体(PRLR)基因在撒坝猪群体中的多态性分布,并采用最小二乘分析模型初步统计分析基因多态性与部分生产性能的相关性。结果表明,PRLR基因等位基因B及其基因型BB在群体中占优势,频率分别为0.6594和0.4438;PRLR基因在群体中处于Hardy-Weinberg平衡状态;头胎繁殖性状有利等位基因B对生长性状无不利影响。     

日粮中添加牛至油对河西绒山羊育肥性能的影响研究

牛至精油对家畜生产性能和免疫力的提高有重要的影响。通过在日粮中添加牛至精油育肥河西绒山羊,研究其对河西绒山羊生长性能、屠宰性能及胴体品质的影响。对照组饲喂基础日粮,试验组在饲喂的基础日粮中分别添加4和7 g宜生饲宝(含牛至精油的添加剂),4和7 g宜生饲宝中牛至精油的含量分别为52和91 mg。对照组和试验组均为同月龄、同体重的河西绒山羊羯羊,试验组和对照组均设3个重复,每个重复5只羊。育肥期为90 d,每30 d为1个阶段。试验结果表明:育肥全期,对照组、4 g组和7 g组河西绒山羊平均日增重分别为96.30、172.22和169.82 g·d^-1,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05);屠宰性状,胴体重对照组、4 g组和7 g组分别为20.24、24.18和23.90 kg,无显著差异(P>0.05),屠宰率对照组、4 g组和7 g组分别为48.86%、51.21%和51.56%,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05),胴体净肉重对照组、4 g组和7 g组分别为12.90、16.27和15.99 kg,4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05);肉质性状,大理石纹4 g组和7 g组分别显著高于对照组(P<0.05),4 g组和7 g组无显著差异(P>0.05),pH、熟肉率、失水率、嫩度、蒸煮损失对照组、4 g组、7 g组间均无显著差异(P>0.05)。日粮中添加牛至油可以显著提高河西绒山羊的育肥性能,本试验日粮中添加4 g宜生饲宝(含牛至精油52 mg)效果最佳。     

Assessing exterior egg quality indicators using machine vision

ABSTRACT

1. The objective of this study was to develop a machine vision method for analysing exterior parameters of chicken eggs to automate the stage of primary sorting.

2. The developed algorithm based on predetermined thresholds calculated egg quality indicators, including geometric dimensions, shape index and the mottling grade. The algorithm was implemented with an experimental setup that combined the image-based and the candling methods. A total of 400 egg samples were analysed.

3. Comparison of results of the algorithm with those obtained using the traditional manual method showed that mean value of radii values difference was 0.095 ± 0.058 mm for the sharp and 0.080 ± 0.047 mm for the blunt end of the egg, with standard deviations of 0.58 mm and 0.49 mm, respectively.

4. The correlation coefficient between the shape index values determined by the two methods was 0.93; the standard deviation of absolute differences between corresponding values was 1.05%.

5. The results of mottling grade estimation were compared using F-measure and confusion matrix.

6. The results allow the possibility to perform the assessment of egg exterior quality factors in an automatic mode, independent of the expertise of a grader.     

In situ provision of drinking water to grazing dairy cows improves milk production

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.     

Innovative layer genetics to handle global challenges in egg production

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.     

The effect of dietary supplementation with Aurantiochytrium limacinum on lactating dairy cows in terms of animal health,productivity and milk composition

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.