高温高湿条件下添加功能性油脂对奶牛生产性能、瘤胃发酵和生理状态的影响

文章旨在评估功能性油脂替代莫能菌素对高温高湿环境下奶牛生产性能、瘤胃发酵和生理状态的影响。试验选择产奶期(200±50)d,平均体重(600±75)kg的荷斯坦奶牛36头,将其随机分为3组,每组12个重复,每个重复1头牛,进行为期6周的试验(1周适应期,5周试验期),试验共设计3种日粮,对照组饲喂基础日粮,处理1组在基础日粮添加20mg/kg莫能菌素,处理2组在基础日粮添加0.05%功能性油脂。试验期间环境温度、湿度和温湿度指数分别是(25±0.55)℃、(82.0±1.20)%和74.5±0.30,表明奶牛处于高温高湿环境。结果:处理1组较对照组和处理2组显著降低了干物质和有机物的摄入量(P<0.05),较对照组显著降低了粗蛋白质摄入量(P<0.05)。试验时间显著影响有机物、蛋白质摄入量及养分表观消化率(P<0.05),同时显著影响瘤胃pH、氨氮和挥发性脂肪酸含量(P<0.05)。对照组较处理2组显著降低了血清尿素含量(P<0.05),处理和时间对血清尿素含量的影响具有显著交互效应(P<0.05)。处理1组较处理2组显著降低了脂肪产量和乳脂肪含量(P<0.05)。试验时间显著影响乳成分含量及产量(P<0.05)。结论:在本试验条件下,功能性油脂增加了乳脂产量,并且可以代替莫能菌素而不影响奶牛在高温高湿环境下的采食量、养分消化率、瘤胃发酵和生理状态。     

种公牛的饲养管理技术

种公牛是提高牛群质量最关健的因素,一头种公牛自然交配,与配母牛一年大约几百头。利用人工授精技术每年比本交能增加几倍。而用牛冷冻精液结合人工授精技术进行冷配每年配种母牛数量少则上万头,多则几万头。本文从饲养种公牛的基本要求出发,对种公牛的特性,营养与日常饲养管理、防疫和疾病防治,以及安全生产多方面做了整理介绍,以供同行参考。     

天然黄色茧蚕品种实验室比较与生产应用试验

经过对新育成的黄色茧品种与生产应用白色茧品种秋丰×白玉的对比试验及丝质鉴定,秋丰×黄,正反交、秋丰×HJ,正反交这两对黄色茧品种具有龄期短、抗病力强、虫蛹率高的优点;黄色茧品种的产茧量与对照种相比差距不显著;两对黄色茧品种的鲜茧出丝率等茧丝质指标略低于对照,解舒丝长达到750m左右,解舒率均在65％以上,净度优良,符合缫丝业对茧质的基本要求。对其中的秋丰×HJ7在农村进行规模化中秋蚕饲养与缫丝应用试验,符合生产应用要求。     

肉牛母牛生产瘫痪的防治

[目的]为了掌握张掖肉牛母牛生产瘫痪的发生与治疗方法。[方法]对一例产前瘫痪母牛和一例产后瘫痪母牛进行药物治疗。[结果]两例生产瘫痪母牛经过准确诊断和及时合理治疗得到康复。[结论]生产瘫痪是发生于高产奶牛的代谢性疾病,但近年来张掖肉牛母牛偶有发生,对张掖肉牛母牛生产瘫痪的治疗,只要诊断正确,治疗及时,合理用药,定能取得满意的治疗效果。     

不同播种方式对岷山红三叶草产量的影响

通过在海拔2 450 m的岷县南部高寒阴湿地区进行岷山红三叶Trifolium pratense cv.Minshan干草丰产栽培试验,得到以下结论：条播为岷山红三叶进行干草生产的最佳播种方式,行距以20 cm最为理想,该行距下生长速度快,而且产草量最高。播种当年A组（行距20 cm）鲜草产量比对照组(撒播)高出4 987.5 kg/hm2,是对照组的1.27倍,差异极显著（P＜0.01）;A组鲜草产量比B组（行距40 cm）高101 kg/hm2,差异显著（P<0.05）。生长第2年,A组鲜草产量均高于对照组和B组,是对照组的1.16倍,差异极显著（P＜0.01）,是B组的1.02倍,差异显著（P＜0.05）。不同播种方式对岷山红三叶鲜干比无影响。     

批次化生产在猪场疫病净化中的重要作用

随着中国养猪业规模化、集约化发展步伐的加快,养猪生产正在从劳动密集型的连续生产方式过渡到智能化、批次化养猪的管理新模式,与之相伴而来的是猪新旧疫病的不断发生,其仍然是养猪生产面临的重大挑战,尤其是近两年非洲猪瘟防控形势非常严峻,猪场在疾病防控、生物安全方面遇到了新挑战。批次化生产模式可以使传统连续饲养方式造成的疫病传播得到阻断,在养猪生产中具有重要的实践意义。文章综述了批次化生产的概念、批次化生产在猪场疫病净化中的重要作用。     

Identification of potential genomic regions for egg weight by a haplotype-based genome-wide association study using Bayesian methods

ABSTRACT

1. Theoretically, haplotype blocks might be a more suitable alternative to SNP genotypes as they are usually better at capturing multi-allelic QTL effects, compared to individual SNP genotypes in genome-wide association studies. The objectives of this study were to identify genomic regions related to egg weight traits by Bayesian methods (BayesA, BayesB, and BayesN) that fit fixed-length haplotypes using GenSel software.

2. Genotypes at 294,705 SNPs, that were common on a 600K Affymetrix chip, were phased for an egg-laying hen population of 1,063 birds. Recorded traits included first egg weight (FEW) and average egg weight at 28, 36, 56, 66, 72 and 80 weeks of age.

2. Fitting 1Mb haplotypes from BayesB resulted in the highest proportion of genetic variance explained for the egg weight traits. Based on the trait, the genetic variance explained by each marker ranged from 27% to 76%.

3. Different haplotype windows associated with egg weight traits only explained a small percentage of the genetic variance.

4. The top one 1-Mb window on GGA1 explained approximately 4.05% of total genetic variance for the FEW. Candidate genes, including PRKAR2B, HMGA2, LEMD3, GRIP1, EHBP1, MAP3K7, and MYH were identified for egg weight traits.

5. Several genomic regions, potentially associated with egg weight traits, were identified, some of which overlapped with known genes and previously reported QTL regions for egg production traits.     

Evaluation of feeding spray-dried bovine plasma protein on production performance of laying hens exposed to high ambient temperatures

The purpose of this study was to evaluate feeding 2 levels of spray-dried bovine plasma protein (SDP) on production performance of laying hens subjected to high ambient temperatures. Two groups of 96 Hy-Line W-98 hens (38 wk of age) were housed in each of 2 environmentally controlled chambers. At 40 wk of age, all hens were fed 3 diet treatments consisting of (1) a control diet (0% SDP); (2) the control diet supplemented with 0.75% SDP; and (3) the control diet supplemented with 1.50% SDP. Hens in each chamber (8 cages of 4 hens per cage) were ad libitum fed 1 of each diet for 5 wk. The heat stress (HS) chamber was maintained at 21°C (wk 1), 29°C (wk 2), and 35°C (wk 3 to 5). The thermoneutral chamber was maintained at 21°C during wk 1 to 5. A significant main effect of week was observed for hens maintained in the HS chamber for egg production, egg weight, egg mass, and feed consumption, which resulted in acute heat stress causing a reduction in these parameters. Hens fed the 1.50% SDP diet in the HS chamber produced greater (P < 0.05) egg mass on average than hens fed the control or 0.75% SDP diet (wk 1 to 5). During the second week of acute HS (wk 4), hens fed the control and 1.50% SDP diets had greater (P < 0.05) egg production than those fed the 0.75% SDP diet. During wk 5, hens in the HS chamber that were fed the 1.50% SDP diet produced more (P < 0.05) eggs than those fed the control diet. Therefore, based on the results of this study, acute HS negatively affected short-term production performance. In addition, feeding hens an SDP-supplemented diet may have a slight positive effect on production performance when maintained in acute HS conditions.     

环峡南苜蓿种子生产技术研究

对影响环峡南苜蓿种子产量的磷肥、钾肥、浇水和地膜条件4个因素进行正交组合试验,结果表明: 磷肥、钾肥、磷钾肥互作对种子产量的影响较大,其次为地膜条件、磷肥浇水互作,浇水的影响最小。试验结果和生产成本综合考虑,最适宜的处理组合为:钙镁磷450 kg/hm2+硫酸钾150 kg/hm2+不铺地膜+不浇水。     

超临界萃取技术及其在蜂产品加工中的应用

本文简要介绍了超临界萃取技术及其在蜂产品提取中的应用。