Measuring teat dimensions using image analysis

The interaction between teat and teatcup liner can strongly affect the milking characteristics and udder health. Therefore teat morphology is an important parameter in choosing the most appropriate liner. Nevertheless, teat morphology is rarely considered in choosing a teatcup liner. Gathering information on teat morphology on large scale with current techniques is time consuming, subjective and not always accurate. However, the ability to measure teat shape parameters in an easy way and on large scale has many applications. This study presents a new vision based measuring system that uses a camera to obtain a 2D image of the teat and image processing analyses to determine teat length and diameters. The technique is proven to be accurate (error less than 6%), repeatable and reproducible for both teat length and diameters

Repeatability of dispersal behaviour in a common dwarf spider: evidence for different mechanisms behind short- and long-distance dispersal

Abstract: 1. The response of dispersal towards evolution largely depends on its heritability for which upper limits are determined by the trait's repeatability. 2. In the Linyphiid spider E. atra, we were able to separate long- and short-distance dispersal behaviours (respectively ballooning and rappelling) under laboratory conditions. By performing repeated behavioural trials for females, we show that average dispersal trait values decrease with increasing testing days. By comparing mated and unmated individuals during two periods (before and after mating for the mated group, and the same two periods for the unmated group), we show that mating has no effect on the mean displayed dispersal behaviour or its within-individual variation. Repeatabilities were high and consistent for ballooning motivation, but not for rappelling. 3. Ballooning motivation can be regarded as highly individual-specific behaviour, while general pre-dispersal and rappelling behaviours showed more individual variation. Such difference in repeatability between long-and short-distance dispersal suggests that short-and long-distance dispersal events are triggered by different ecological and evolutionary mechanisms

Variance components of teat dimensions in dairy cows and associated factors

Traditionally, all cows within a herd are milked with the same teat cup liner, although it is hypothesized that considerable variation in teat dimensions exists between cows and quarters within cows. To study at which level (herd, cow, or quarter) most variation in teat dimensions resides, and to identify factors explaining (part of) this variation, both a cross-sectional (n = 2,715) and a longitudinal study (n = 8,678) were conducted. Using an objective and easy-to-use measuring device, teat length and teat diameters were determined In both studies, most variation in teat dimensions was present at the cow or within-cow level, and not at the herd level, indicating that choosing a teat cup liner that is identical for all cows in a herd is far from optimal. Quarter position (front versus hind), parity and lactation stage were identified as factors associated with teat length and teat diameters. Generally, front teats were longer and broader than hind teats. Teat length and diameters increased with parity, although the increase in teat length was not significant from second parity onwards in front teats, based on observations from the longitudinal study. After the first 30 d in milk, teat length substantially and significantly increased, whereas teat diameters decreased. We conclude that better results in teat condition, and eventually in udder health, might be yielded when different teat cup liners are chosen for front versus hind teats or for cows of different parity or lactation stage, with special attention to the first 30 d in milk. However, the biological relevance of these differences should be examined first

Thermal conditions during juvenile development affect adult dispersal in a spider

Abstract: Understanding the causes and consequences of dispersal is a prerequisite for the effective management of natural populations. Rather than treating dispersal as a fixed trait, it should be considered a plastic process that responds to both genetic and environmental conditions. Here, we consider how the ambient temperature experienced by juvenile Erigone atra, a spider inhabiting crop habitat, influences adult dispersal. This species exhibits 2 distinct forms of dispersal, ballooning (long distance) and rappelling (short distance). Using a half-sib design we raised individuals under 4 different temperature regimes and quantified the spiders' propensity to balloon and to rappel. Additionally, as an indicator of investment in settlement, we determined the size of the webs build by the spiders following dispersal. The optimal temperature regimes for reproduction and overall dispersal investment were 20 °C and 25 °C. Propensity to perform short-distance movements was lowest at 15 °C, whereas for long-distance dispersal it was lowest at 30 °C. Plasticity in dispersal was in the direction predicted on the basis of the risks associated with seasonal changes in habitat availability; long-distance ballooning occurred more frequently under cooler, spring-like conditions and short-distance rappelling under warmer, summer-like conditions. Based on these findings, we conclude that thermal conditions during development provide juvenile spiders with information about the environmental conditions they are likely to encounter as adults and that this information influences the spider's dispersal strategy. Climate change may result in suboptimal adult dispersal behavior, with potentially deleterious population level consequences

Dust drift during seed drilling – output of a 4 year study

Bee mortality incidents observed in several countries placed a spotlight on a new pathway through which pesticides could get into the environment and cause problems: the emission of pesticide laden dust particles during drilling operations. In 2011, the authors started to look at this relatively new phenomenon and the risks related to it in perspective to current agricultural practices in Flanders. To achieve this objective, an integrated experimental and modelling approach was used. The data and models resulting from this 4 year study could be helpful for risk assessments in other countries as well or to better understand the dust drift phenomenon in general. Some of the first results were already shown at previous IAPA conferences. This paper gives an update with the current knowledge.status: publishe