Ocular complications of oak processionary caterpillar setae in the Netherlands; case series, literature overview, national survey and treatment advice.

During early summer 2019, the Netherlands experienced an outbreak of the exotic oak processionary caterpillar. The vast number of caterpillars, which live in large nests on oak trees before they turn into moths, possess thousands of small, barbed hairs (setae) that are disseminated with the wind. The hairs cause a range of primarily dermatologic problems. However, Dutch ophthalmologists started reporting patients with ophthalmologic complaints caused by the penetrating hairs of the oak processionary caterpillar. This paper focuses on the ophthalmologic complications caused by the caterpillar hairs. We collected a series of four cases with reports ranging from a corneal erosion with hairs lodged into the cornea, to a sterile endophthalmitis in which hairs were found in the vitreous. A literature review for similar cases was performed using the PubMed and Embase database. Together with the Dutch Ophthalmic Society (Nederlands Oogheelkundig Gezelschap, NOG), a national survey was issued to determine the scale of this new problem. This showed that oak processionary caterpillar related complaints are primarily limited to the south of the Netherlands. Suggested ophthalmic treatment guidelines are presented. With the next summer at the doorstep, and limited preventative measures against the caterpillar hairs, we expect a new wave of ophthalmologic complaints coming year as well.

Effect of natural infection with minor pathogens on susceptibility to natural infection with major pathogens in the bovine mammary gland.

OBJECTIVE: To evaluate the effect of natural udder infection with minor pathogens on subsequent natural infection with major pathogens. SAMPLE POPULATION: 7 dairy herds with low bulk milk somatic cell count. PROCEDURE: During a 20-month prospective study, milk samples were collected from diary cows at regular intervals and from quarters with clinical signs of mastitis. Incidence of intramammary infection was calculated in uninfected quarters and in quarters infected with minor pathogens. A within-cow, matched case-control analysis was used to evaluate the effect of minor pathogens on subsequent infection with major pathogens. RESULTS: Quarters infected with minor pathogens had higher somatic cell count than did uninfected quarters. In quarters infected with Corynebacterium bovis, the rate of infection with major pathogens was lower, whereas in quarters infected with coagulase-negative Micrococcaceae, the rate of infection with major pathogens was higher than that in uninfected quarters. From the within-cow comparison, it appeared that, in quarters infected with minor pathogens, infection with major pathogens was significantly lower than that in comparable control quarters not infected with minor pathogens. CONCLUSIONS: Minor pathogens have a protective effect against infection with major pathogens. The protective effect of C bovis against subsequent infection with major pathogens appears to be greater than the effect of coagulase-negative Micrococcaceae.

Detection of oestrus in dairy cows: a new approach to an old problem.

Fertility indices, such as non-return rate and number of services per conception, have worsened significantly over the past few years. Because oestrus detection is one of the major factors influencing these indices, this study was performed to determine whether, how long, and at what time dairy cows show signs of oestrus in their behaviour. Two high producing herds with about 40 open cows were observed for 30 minutes every 2 hours for 6 weeks. The various signs of oestrus were recorded. The milk progesterone concentration was monitored daily to detect ovulation. A scale (Table 2) was composed according to the frequency of these symptoms during and between oestrous periods. This scale was used in order to determine which cows were in oestrus. Each oestrous symptom was given a score and the scores were summed for a 24-hour period. If a score of > 100 points was reached within a 24-h period, the cow was considered to be in oestrus. As used, the oestrus detection scale proved to be very convenient. Because standing oestrus was observed in only 37% of the oestri, this criterion had a very low sensitivity for oestrus detection. With the use of this scale and 12 observations per day, we reached a detection rate of 100%. If a more practical observation scheme would have been used (e.g. observing the herd twice daily, for 30 min) lower threshold values would have been obtained. This observation scheme resulted in a detection rate of 74% with no incorrect assessments.

The effect of discontinuation of postmilking teat disinfection in low somatic cell count herds. I. Incidence of clinical mastitis.

Results are described of a split-udder trial on the effect of discontinuation of postmilking teat disinfection on the incidence of clinical mastitis in seven dairy herds with a low bulk milk somatic cell count and a high incidence of clinical mastitis. Overall incidence of clinical mastitis was non-significantly lower (18%), whereas the incidence of the most prevalent pathogen associated with clinical mastitis, Escherichia coli, was significantly lower in quarters for which postmilking teat disinfection was discontinued. We concluded that discontinuation of postmilking teat disinfection may decrease the incidence of clinical Escherichia coli mastitis in herds for which standard mastitis prevention measures are executed adequately, bulk milk somatic cell count is low, and incidence of clinical mastitis is high. However, because an increase in intramammary infections with contagious pathogens may occur, care is recommended when advising discontinuation of postmilking teat disinfection.

The effect of discontinuation of postmilking teat disinfection in low somatic cell count herds. II. Dynamics of intramammary infections.

Results of a 20 month split-udder trial on the effect of discontinuation of postmilking teat disinfection on intramammary infections (IMI) with major and minor pathogens in seven dairy herds with a low somatic cell count are described. The incidence of Escherichia coli IMI was found to be significantly lower, whereas the incidence of IMI with Staphylococcus aureus and minor pathogens was significantly higher in quarters for which postmilking teat disinfection was discontinued than in disinfected quarters. It was concluded that discontinuation of postmilking teat disinfection decreased the incidence of E. coli IMI, accompanied by a, from a practical point of view, acceptable rise in somatic cell count. However, the possible increase in the incidence of S. aureus IMI calls for careful monitoring of the dynamics of IMI with contagious pathogens, when postmilking teat disinfection is discontinued in an attempt to reduce E. coli mastitis.

[Udder disinfection and mastitis in cattle: a literature review]. / Tepeldesinfectie en mastitis bij het rund: een literatuuroverzicht.

Postmilking teat disinfection is accepted as an important part of standard preventive measures against mastitis in dairy cattle. The efficacy of postmilking teat disinfection against infections with contagious pathogens such as Staphylococcus aureus and Streptococcus agalactiae is beyond doubt. However, the efficacy of teat disinfection against infections with environmental pathogens such as Escherichia coli is disputed, and a negative effect has even been described in some situations. This article reviews the practice of teat disinfection in dairy cattle. Premilking and postmilking teat disinfection are discussed, as is the efficacy, different ways of teat disinfection, and different disinfectants. It is concluded that post-milking teat disinfection is an effective management measure in most herds. Selection of teat disinfectants should be based on proven efficacy, which is required for registration of the preparation as a veterinary medical product in the Netherlands.

[A closer look at the milking machine]. / De melkmachine nader bekeken.

Machine milking has changed enormously in the past decades. The simple milking machine developed at the end of the nineteenth century has become a complex appliance which removes milk from the udder in a fast and efficient way. There is no doubt about the importance of a well functioning milking machine as regards milk quality and udder health. This article reviews the literature on the basic mechanics of machine milking, with special emphasis on the action of the cluster during milking. The movement of the teat cup liner is particularly important in influencing the efficiency of milk extraction and udder health. Therefore special attention is paid to the operation of the liner, how it works, and how the opening and closing of the liner affects the milking process. The functioning of the pulsator, the vacuum fluctuations occurring during milking, and the effect of these fluctuations on the opening and closing of the liner are discussed. The maintenance of the milking machine is also described.

[Machine milking and udder health: a literature review]. / Melkwinning en uiergezondheid: een literatuuroverzicht.

This article reviews the influence of machine milking on udder health. The main risks are transmission and penetration of pathogens during milking. Pathogens can be transmitted via the hands, cloths, and liners. Irregular fluctuations in the vacuum can cause penetration of mastitis pathogens into or through the teat canal. Such fluctuations are caused by air blasts in the milking machine. Machine milking can also cause teat lesions, although only severe lesions give rise to new infections. Preliminary research results on the influence of the frequency and degree of udder evacuation show that the clinical symptoms of mastitis generally decreases as the frequency and completeness of milking increase. It is concluded that machine milking can influence udder health but that the influence strongly depends on the exposure to pathogens and the quality of the milker.

A knowledge-based system for diagnosis of mastitis problems at the herd level. 1. Concepts.

Much specialized knowledge is involved in the diagnosis of a mastitis problem at the herd level. Because of their problem-solving capacities, knowledge-based systems can be very useful to support the diagnosis of mastitis problems in the herd. Conditional causal models with multiple layers are used as a representation scheme for the development of a knowledge-based system for diagnosing mastitis problems. Construction of models requires extensive cooperation between the knowledge engineer and the domain expert. The first layer consists of three overview models: the general overview conditional causal model, the contagious overview conditional causal model, and the environmental overview conditional causal model, giving a causal description of the pathways through which mastitis problems can occur. The conditional causal model for primary udder defense and the conditional causal model for host defense are attached to the overview models at the second layer, and the conditional causal model for deep primary udder defense is attached to the conditional causal model for the primary udder defense at the third layer. Based on quantitative user input, the system determines the qualitative values of the nodes that are used for reasoning. The developed models showed that conditional causal models are a good method for modeling the mechanisms involved in a mastitis problem. The system needs to be extended in order to be useful in practical circumstances.

A knowledge-based system for diagnosis of mastitis problems at the herd level. 2. Machine milking.

A knowledge-based system for the diagnosis of mastitis problems at the herd level must search for possible causes, including malfunctioning milking machines or incorrect milking technique. A knowledge-based system on general mechanisms of mastitis infection, using hierarchical conditional causal models, was extended. Model building entailed extensive cooperation between the knowledge engineer and a domain expert. The extended knowledge-based system contains 12 submodels underlying the overview models. Nine submodels were concerned with mastitis problems arising from machine milking. These models are briefly described. The knowledge-based system has been validated by other experts after which the models were adjusted slightly. The final knowledge-based system was validated to data collected at 17 commercial dairy farms with high SCC in the bulk milk. Reports containing the farm data were accompanied by recommendations made by a dairy farm advisor. This validation showed good agreement between the knowledge-based system and the dairy farm advisors. The described knowledge-based system is a good tool for dairy farm advisors to solve herd mastitis problems caused by a malfunctioning milking machine or incorrect milking technique.