A survey of northern Victorian dairy farmers to investigate dairy calf management: colostrum feeding and management

Objectives

To describe colostrum management practices carried out in northern Victorian dairy herds and to identify weaknesses in these areas that may affect calf health and welfare by comparing the results with the current industry recommendations

Methods

A questionnaire to obtain information about colostrum management and calf‐rearing practices was sent to commercial dairy farming clients of Rochester Veterinary Practice between June and September 2013. The questionnaire consisted of a general herd overview and colostrum harvesting practices.

Results

The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) time of removal calf from the dam, (2) relying on calf suckling colostrum from the dam to achieve adequate passive transfer, (3) failing to supplement calves with colostrum, (4) feeding inadequate volumes of colostrum, (5) delayed colostrum harvesting, (6) pooling of colostrum, (7) failing to objectively assess colostrum quality or relying on visual assessment and (8) storing colostrum for a prolonged periods of time at ambient temperatures.

Conclusion

The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.

     

Improved milk production through PG–PL system by provision of in‐house shelter management in lactating Murrah buffaloes during winter season

Comprehensive information on the role of β‐casein and plasminogen–plasmin (PG–PL) system in milk secretion of Murrah buffaloes during winter season is lacking, although effects of cold stress can be ameliorated to an extent by altering microclimate at farm level. Hence, this study was aimed to determine the changes in productivity along with PG–PL system of milk, plasma hormones and metabolites of buffaloes during winter (December–January) season under two different management systems. Average minimum temperature and wind chill index during this season were 7.02 and 12.74 °C respectively. Buffaloes were divided in two groups of six animals each: control and treatment, where treatment group animals were placed in‐house with floor bedding of paddy straw and the control group animals in loose housing system without straw bedding. Physiological responses were recorded, and milk and blood samples were collected at weekly intervals for six‐week experimental period. Under in‐house management system, buffaloes experienced better comfort by alleviating environmental stress as their physiological responses such as respiration rate and pulse rate were significantly reduced (p < 0.01) as compared to the control, which subsequently resulted higher milk yield by 9.92% (p < 0.05). Analysis of milk samples revealed higher concentration of plasminogen (10.6 vs. 8.05 μg/ml; p < 0.01) and β‐casein (p < 0.05), and lower plasmin level (0.299 vs. 0.321 μg/ml; p < 0.05) in buffaloes under treatment group. It was also found that plasma cortisol, glucose and non‐esterified fatty acids levels were higher (p < 0.01) in control group as compared to the treatment animals by 13.6%, 8.14% and 12.6% respectively. However, milk composition, growth hormone, epinephrine and norepinephrine level in plasma were similar in both the groups. Hence, it may be concluded that provision of in‐house shelter management with floor bedding of paddy straw during winter was effective to minimize environmental stress and improved milk production through manipulation of PG–PL system in buffaloes.     

Using the indicator amino acid oxidation technique to study threonine requirements in horses receiving a predominantly forage diet

Threonine has been reported to be the second limiting amino acid in typical equine diets, but its actual requirement has not been determined in horses. To evaluate amino acid metabolism and requirements, the indicator amino acid oxidation (IAAO) method has been successfully used in other species. The objective of this research was to estimate threonine requirements in mature horses fed timothy hay and concentrate in 4:1 ratio using the IAAO method. Six Thoroughbred mares (579.9 ± 46.7 kg) received each of 6 levels of threonine intake, 41, 51, 61, 70, 80 and 89 mg/kg BW/day, in a randomly determined order. Each study period was 7‐day long, and on day 6, blood samples were collected before and 90 min after feeding to measure amino acid concentrations using HPLC. On day 7, horses underwent IAAO procedures, which included a 2‐hr primed, constant intravenous infusion of [¹³C]sodium bicarbonate to measure total CO₂ production and a 4‐hr primed, constant oral administration of [1‐¹³C]phenylalanine to estimate phenylalanine oxidation to CO₂. Blood and breath samples were collected to measure blood [¹³C]phenylalanine, using GC‐MS analysis and breath ¹³CO₂ enrichment, using an infrared isotope analyser. Increasing threonine intake levels did not affect plasma phenylalanine oxidation by the ANOVA test (p > 0.05) but resulted in a linear decrease in phenylalanine oxidation (p = 0.04) without a breakpoint by the orthogonal linear contrast. This study is the first attempt to evaluate threonine requirements in horses by the IAAO method; however, threonine requirements are still unknown in mature horses at this time.     

Impact of cold-season grazing and supplementary feeding on rumen metabolic parameters and micro-organisms in the ewes of Gansu Alpine Fine Wool Sheep北大核心CSCD

An experiment was conducted to scientifically identify the appropriate feed for Gansu Alpine Fine Wool ewes in order to change the animals' breeding mode, which currently can only be mated at the age of 2.5 years due to insufficient nutritional supply. The experiment selected 48 12-month-old ewes and randomly divided them into group a (Diet 1), group b (Diet 2), group c (Diet 3), and a control group with no supplementary feeding. The feed test was run for 90 days. The rumen pH of groups a and b were very significantly higher (P<0.01) or group c significantly lower (P<0.05) than control group. The rumen ammonia nitrogen, protein nitrogen and total nitrogen of groups a, b and c were all higher than control group (P<0.01). The total volatile fatty acids of group a and b were all higher than the control group (P<0.01), group b significantly higher than group c (P<0.05). The molar ratio of acetic acid and propionic acid in group a was very significantly higher than control group (P<0.01), group b and c were significantly higher than control group (P<0.05). The molar ratio of butyric acid in group a was very significantly higher than group c (P<0.01). The ratio of acetic acid and propionic acid in group b was significantly lower than control group (P<0.05). The number of several rumen fiber-degrading bacteria and protozoa in groups a, b and c were very significantly (P<0.01) or significantly (P<0.05) higher than the control. In conclusion, this study shows that supplementary feeding can positively affect the rumen metabolic parameters and the number of several rumen microorganisms in Gansu Alpine Fine Wool ewes. In general, the effects of Diet 1 were the strongest, while Diet 2 also produced notable improvements. © 2018, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

新型冠状病毒肺炎疫情下武汉市粮食应急管理经验与启示——基于权变理论视角的分析

阐析新型冠状病毒肺炎疫情对粮食安全的冲击及其诱发危机的特征,引入权变理论,分析粮食应急管理中的权变思想,构建权变理论下的粮食应急决策模型和应急管理框架.在此基础上,从监测预警机制、应急管理体制、应急保障机制,以及常态化疫情防控机制等体制机制层面探析武汉市粮食应急管理经验.融合权变理论,从管理者的权变素质、应急组织的敏捷...     

长江口南支水域刀鲚仔稚鱼资源量的年度变化

为了进一步探明长江口南支刀鲚(Coilia nasus)仔稚鱼的分布和丰度变化,2018年6-10月在长江口南支设置8个站点,采用大型仔稚鱼网(口径1.3m,网目0.5mm)在每月大潮期间按月进行表层水平拖网调查,研究结果与2014年、2015年同水域和同期的研究结果比较,旨在揭示长江口南支刀鲚仔稚鱼资源的年度变化。本研究共拖网58网次,采集刀鲚仔稚鱼4611尾,平均密度0.123 ind./m3,体长范围3.1～61.74mm,发育阶段从前弯曲期到稚鱼期,其中前弯曲期仔鱼(3.1～18.12mm)最多,占总数86.19%,其次是弯曲期仔鱼(4.9～24.05mm),占8.5%,后弯曲期仔鱼(9.75～30.36mm)和稚鱼(24.22～61.7mm),分别占4.6%和0.72%。白天涨潮采集刀鲚仔稚鱼4271尾,平均体长11.18mm,平均密度0.169 ind./m3,退潮时采集336尾刀鲚仔稚鱼,平均体长10.52mm,平均密度(0.029 ind./m3)低于涨潮密度;St.8夜间涨退潮调查显示,涨潮密度(0.005 ind./m3)大于退潮密度(0.002ind./m3)。三年间刀鲚仔稚鱼发育阶段组成,2014年以卵黄囊期仔鱼为主,2015年和2018年均以前弯曲期仔鱼为主。各年刀鲚仔稚鱼出现的持续时间和高峰期基本相似,主要在6-8月出现,9-10月出现量极少。三年仔稚鱼密度分布表明,各站位点以及各月平均密度差异均不显著(P＞0.05)。     

根际生命共同体：协调资源、环境和粮食安全的学术思路与交叉创新

植物营养学研究近年来在植物养分高效分子机理、植物-微生物互作、根际互作与微生态调控、农田养分管理等研究领域取得了一系列原创性进展。然而,当前如何协调粮食安全、资源高效和环境可持续性仍面临巨大挑战。针对这一重大问题,本文提出"根际生命共同体(Rhizobiont)"学术思路,围绕"根际互作与养分高效"这一重大科学命题,构建"植物-根系-根际-菌丝际-土体及其微生物"根际生命共同体理论体系,突破植物-微生物、微生物-微生物关键界面互作机制,阐明根际生命共同体结构、功能及其在养分活化、吸收与利用中的作用机制,建立共同体多界面互作增效的生物学调控新途径,开辟植物-土壤-微生物交叉创新领域,根际生命共同体理论创新有助于破解粮食安全、资源高效、环境保护多目标协同的难题,支撑我国农业绿色发展。文章指出了根际生命共同体与养分高效研究的重点方向与内容,尤其是深入揭示和调控植物第二基因组——微生物组的作用正成为农业科学的研究前沿。     

植物寄生线虫效应蛋白调控寄主防卫反应分子机制研究进展

在植物寄生线虫与寄主互作过程中,线虫分泌器官如食道腺细胞分泌的效应蛋白在寄主细胞壁修饰和调控寄主免疫反应以及取食位点形成和维护中发挥着关键作用。解析植物寄生线虫关键效应蛋白的功能及其与寄主互作机制将为探索植物寄生线虫防控新策略提供重要的理论基础。本文从效应蛋白降解寄主细胞壁、调控寄主基础免疫反应、诱导免疫反应机制和介导翻译后修饰调控寄主免疫反应以及植物激素代谢途径的调控机制等方面进行了概述。     

基于粮食安全保障体系的经济管理与政策效应分析

探讨了粮食安全保障体系,即粮食安全的基本概念、保障体系的结构、经济管理机制以及政策效应。粮食安全概念包含四个方面：粮食获取、可达性、利用效率及供应稳定性,其不仅关乎总体生产规模,还涉及资源分配与市场运作。生产力、储备、运输、分配、消费以及政策与管理等多个环节构成了保障体系的架构。经济管理机制的核心关注点包括宏观经济政策、市场调控以及应对市场波动的策略。通过跨国案例研究,揭示了政策在推动农业产出、加强市场稳健性和提升农民生活品质等方面的具体作用。