A survey of beef cattle farmers in New Zealand,examining management practices of primiparous breeding heifers

AIM: To obtain an estimate of the incidence of assistance at calving in primiparous (first-calving) beef heifers and the prevalence of breeding heifers at 15 months of age in New Zealand in 2006,and to identify factors contributing to farmers' decisions regarding breeding strategies for heifers, using a survey of beef cattle farmers.

METHODS: A questionnaire was sent to farmers listed in a Massey University database and to members of selected breed societies, as well as published in an industry newspaper; 331 valid responses were received. Information was gathered on the age and number of primiparous heifers, number of heifers assisted, and the importance of various reasons for and against breeding heifers at 15 months of age. Respondents were also required to outline the criteria used for selecting bulls to join with heifers, and the strategies used to manage dystocia in primiparous heifers.

RESULTS: Sixty-five (95% CI=58–71)% of respondents had only 2-year-old primiparous heifers in 2006, whilst a further 11 (95% CI=8–16)% had both 2- and 3-year-old primiparous heifers. The mean reported incidence of assisted calving was 7.0 (95% CI=6.4–7.5)% for 2-year-old primiparous heifers and 1.7 (95% CI=1.2–2.2)% for 3-year-old primiparous heifers. The reported incidence of assistance at calving within individual herdsranged from 0 to 100% for 2-year-old heifers. Respondents with bull-breeding herds most commonly observed their primiparous 2-year-old heifers twice daily, whilst respondents with commercial herds most commonly observed them once daily during calving. The most important reason for breeding heifers at 15 months of age was “increased profit”, whereas the most important reason for not breeding them at that age was “concern about rebreeding performance of 2-year-old heifers”. Estimated breeding value (EBV) for birth weight was the factor considered most frequently when selecting bulls to join with maiden heifers; age of bull and body shape of bull were the next most frequently considered factors. Selection of an appropriate bull was the most common strategy used to manage dystocia in 2-year-old beef heifers.

CONCLUSIONS: The majority of respondents calved their heifers at 2 years of age, and “increased profit” was the primary motivator. Concern about the rebreeding performance of 2-year-old heifers was the most important reason among the remainder of respondents for not breeding heifers at 15 months of age. Dystocia in 2-year-old heifers was “not a problem” or “a minorproblem” in most herds, but there was much variation amongst herds.     

The physiological and physical status of single calves at birth in a dairy herd in New Zealand

AIM: To determine the physiological status of calves at birth and the perinatal factors that might predispose newborn calves to debility and death, using criteria previously established for newborn lambs.

METHODS: Friesian mixed-aged cows and heifers on a dairy farm in New Zealand that were close to calving were separated from the main herd and observed 24 h a day until they calved. Cows in which labour did not progress for over 1 h or which were in distress were assisted. About 12–13 min after birth, rectal temperature was measured and a blood sample was taken from each calf. The packed cell volume (PCV) and plasma lactate, glucose and fructose concentrations were determined. The time to stand for each calf and the air temperature and weather conditions at birth were recorded.

RESULTS: The parameters measured were within normal ranges for newborns for the majority of calves. Calves sired by an Angus bull and born to heifers (AngusX) had significantly higher plasma lactate and fructose concentrations than Friesian calves born to cows, but there were no significant differences between the two breeds in any of the other parameters measured. Calves of both breeds born with assistance had significantly higher plasma lactate concentrations than those born without. Friesian calves that were assisted at birth had significantly lower PCvs and took significantly longer to stand than calves born without assistance. Assisted AngusX calves were significantly heavier than their unassisted counterparts. Calves born during windy and wet weather and when air temperatures were below 10°C had lower rectal temperatures, took longer to stand and had higher plasma glucose concentrations than those born in dry weather and when air temperatures were above 10°C.

CONCLUSIONS: Calves with physiological parameters outside the normal range had experienced difficult labour and/or intrapartum hypoxaemia. Placental insufficiency and maternal undernutrition during late pregnancy did not apparently contribute to neonatal problems in the present study.     

Successful Management of a Case of Pregnancy Failure in a Degu (Octodon degus)

A 3-month-old female degu (Octodon degus) was presented because blood was noticed in its cage. On physical examination, firm masses were palpable within the caudal abdomen and traces of blood appeared to be coming from the patient’s vaginal opening. Radiographic images showed areas of ill-defined mineralization within the uterus, consistent with fetus formation. Three fetuses could be identified. Ultrasound examination of the degu failed to confirm viable fetal heartbeats. Pregnancy failure with fetal death was suspected. Overnight 1 fetus was passed, but medical therapy with oxytocin failed to induce delivery of the 2 remaining fetuses by the following morning. The degu was therefore anesthetized, an ovariohysterectomy was performed, and the patient made an uncomplicated recovery. Histopathological examination of the fetuses failed to identify any abnormalities. In the uterus, histology confirmed a minimal to mild diffuse, chronic active endometritis. The definitive cause of fetal death was not identified.     

上市公司高管腐败对经营业绩的危害及鉴证研究

选取2013~2014年发生高管腐败的49家上市公司作为相关样本和未发生高管腐败的49家上市公司作为配对样本,运用二元逻辑回归模型和多元线性回归模型进行实证研究后发现：高管腐败对经营业绩有显著危害。CEO权力强度、股权分散性、股权流动性与高管腐败显著正相关,股权制衡度与高管腐败显著负相关,董事会规模、独立董事占比与高管腐败低度正相关,股权集中度、监事会规模、CEO相对薪酬与高管腐败低度负相关。     

内生型农民合作组织的发展与运行机制研究——基于A村牛联合放养组织的实证研究

文章采用实证研究方法,通过对A村牛联合放养组织发展的三个阶段,即牛联合放养组织雏形的出现、牛联合放养组织的快速发展和牛联合放养组织的稳定发展进行分析,从治理、风险保障、自我服务和信誉四个方面对内生型农民合作组织的运行机制进行了深入研究,并提出了需求、乡土文化和农民主体能动性在内生型农民合作组织发展过程中的作用,以期为农民合作组织的发展提供一定的借鉴。     

基于解析法的管道清灰机器人操作臂分析及仿真

以管道清灰机器人为研究对象,建立了该机器人操作臂机构简图。利用解析法对机器人操作臂位置、速度、加速度进行了分析,给出了末端操作器的位置、速度、加速度解。利用Matlab编制计算程序,基于Simulink建立了仿真模型,对管道清灰机器人进行了动态仿真,验证了运动分析的正确性。     

超声波农机作业深度测量装置设计与试验

介绍一种超声波式农机作业深度测量装置,该装置在探头结构、参数选择、超声波发射、回波接收电路及单片机测量控制系统的设计等方面,充分考虑了田间作业环境的特点,采用低声频、单探头、回波信号延迟接收、放大器增益按指数规律增大、重复采集、数字滤波等措施,提高了测量装置的稳定性、可靠性。试验表明该装置的测量精度明显优于电阻应变式耕深测量装置。     

我国海洋捕捞渔业经营机制实证研究

选择全国海洋渔业重点市——浙江省舟山市作为典型,运用经济模型对我国海洋捕捞渔业经营机制的改革与海洋捕捞渔业生产力发展的关系进行了实证分析,并结合目前我国海洋捕捞渔业经营机制中的个体独资经营、股份合作经营和股份制公司存在的制度缺陷,对经济模型分析的结论进行了现实层面的探讨,并提出了进一步完善和创新海洋捕捞渔业经营机制的基本思路。     

Comparison and Analysis of Service Modes on Mobile Libra~

随着科技的进步和时代的发展,结合移动互联网技术、WAP技术、数字图书馆技术的移动图书馆应用研究应运而生。论述了多种移动图书馆服务方式的理论概念及其应用,探讨智能手机操作系统在数字图书馆移动信息服务方式中的优势。