Comparison of three methods for gastrointestinal nematode diagnosis determination in grazing dairy cattle in relation to milk production (original) (raw)
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Veterinary Parasitology, 2014
To investigate future tools for targeted selective treatment against gastrointestinal nematodes (GIN) in adult dairy cows, we evaluated herd and individual cow factors associated with the post-treatment milk production (MP) response over time. A field trial involving 20 pasturing dairy herds in Western France was conducted in autumn 2010 and autumn 2011. In each herd, lactating cows were randomly allocated to a treatment group (fenbendazole) (623 cows), or a control group (631 cows). Daily cow MP was recorded from 2 weeks before until 10 to 14 weeks after treatment. Individual serum anti-Ostertagia antibody levels (expressed as ODR), pepsinogen levels, faecal egg count (FEC), and bulk tank milk ODR were measured at the time of treatment. Moreover, in each herd, information regarding heifers' grazing and treatment history was collected to assess the Time of Effective Contact (TEC, expressed in months) with GIN infective larvae before the first calving. TEC was expected to reflect the development of immunity against GIN, and TEC = 8 months was a cautious threshold over which the resistance to re-infection was expected to be established. Daily MP averaged by week was analyzed using linear mixed models with three nested random effects (cow within herd and herd within year). The overall treatment effect was significant but slight (maximum = +0.85 kg/d on week 6 after treatment), and the evolution of treated cows' MP differed significantly according to several factors. At the herd level, cows from low-TEC herds responded better than cows from high-TEC (≥8 months) herds; cows from herds in which the percentage of positive FEC was >22.6% (median value) responded better than those from herds where it was lower. At the individual cow level, primiparous cows, cows with days in milk (DIM) < or = 100 at the time of treatment, and cows with low individual ODR (< or = 0.38) responded better than multiparous cows, cows with DIM > 100, and cows with higher ODR, respectively.
Epidemiology and effects of gastrointestinal nematode infection on milk productions of dairy ewes
Parasite, 2009
66 Pampinta breed ewes were studied during milking to evaluate the infection and the effect of gastrointestinal nematode on milk production sheep system. Naturally infected ewes on pasture were randomly allocated to two groups: TG, suppressively treated group every four weeks with levamisole and UG, untreated group. Faecal nematode egg counts and larval differentiation were conducted monthly. Successive groups of worm free tracer lambs were grazed with ewes and then slaughtered for worm counts. Test-day milk yield of individual ewes was recorded and ewe machine-milking period length (MPL) were estimated. Faecal egg counts and tracer nematode numbers increased towards midsummer and declined sharply toward the end of the study. TG (188.0 ± 60 liters) produced more (p < 0.066) milk liters than UG (171.9 ± 52.2) and TG had significantly more extended (p < 0.041) MPL than those of UG. The present study showed that dairy sheep were negatively affected by worms, even when exposed to short periods of high acute nematode (mainly Haemonchus contortus) infection.
Veterinary parasitology, 1992
The epidemiology and the effects of nematode infections on cow-calf systems were followed from 3 weeks before calving to 7 months afterwards. Two groups, each of 15 cow-calf pairs grazed on separate lucerne pastures. Group I (GI) were treated monthly with oxfendazole (4.5 mg kg-1), cows being dosed from calving and calves starting 45 days later. Animals in Group II (GII) were not treated. The egg output of the cows was very low. An increase was recorded 2 months after parturition, consisting mainly of Ostertagia spp. The egg output and worm burdens of calves remained low until late summer and reached a peak in autumn. Ostertagia, Cooperia and Haemonchus were the main genera recovered from slaughtered calves. The pasture contamination and tracer calf worm counts remained consistently low until autumn when they began to increase. Inhibited early fourth stage larvae of Ostertagia were recovered during spring. After calving, the live-weight gains (LWG) of treated GI cows were significan...
Veterinary Parasitology, 2007
A detailed study of the epidemiology of subclinical nematode infections in adult dairy cows was conducted on five wellmanaged English dairy farms during the 2002 grazing season. These same farms had also participated in a similar study in 1978-1979 and thus provided a unique opportunity to compare the epidemiological findings after an interval of over two decades. Common factors, including the prevalence of infection, faecal worm egg output, pasture larval count and nematode genera present, and estimated daily larval intake at pasture, were compared between the two studies. Subclinical roundworm burdens, as judged by faecal egg counts, were widespread in dairy cows in 2002, but the prevalence of animals with patent infections and the magnitude of the worm egg output were significantly lower than in 1978-1979. Both the prevalence of infection and mean faecal worm egg output exhibited a marked seasonal peak during the summer months in 2002. Pasture larval numbers were, however, nearly three times higher in 2002 with Ostertagia dominating the nematode genera to which cows were exposed at pasture in both surveys. Factors considered likely to account for differences in parasite epidemiology include the marked increase in herd productivity over the intervening period, the increased proportion of Holstein genetics with the consequent increase in milk yield and feed intake, changes in grassland management and increased stocking rate seen on the majority of farms.
Veterinary Parasitology, 2004
Forty spring-calving cows and heifers (20 of each) were allowed to acquire infection with gastrointestinal (GI) nematodes naturally during grazing. The control group (10 cows and 10 heifers) were compared with 20 similar animals treated with eprinomectin in order to evaluate the effect of GI nematodes on grazing behaviour, milk production, body condition score and live weight. The animals were paired according to parity and milk yield during the week prior to treatment, then within replicate pair randomly allocated to a different treatment group. The grazing area was subdivided into 20 replicated paddocks of equivalent size and topography. Grazing pairs of either control or treated animals were randomly assigned to each paddock over the duration of the study (one pair per paddock). Grazing behaviour was recorded for both groups over a 10-day period commencing 4 days after treatment with eprinomectin. Milk yield was recorded daily and milk quality was recorded weekly. Live weight and body condition score were recorded on the day of allocation, the day of initial treatment and thereafter at weekly intervals until the end of the 4-week trial. Faecal samples were collected from each animal prior to, and after, allocation and submitted for counts of nematode eggs. Additional faecal samples were taken at the end of the study for culture and nematode identification. Individual faecal samples were also analysed for residual digestibility. Pasture samples for nematode larval counts were taken at the same time as faecal sampling. The parasitological results showed low levels of faecal nematode egg output throughout the study, with
Veterinary Parasitology, 2013
This study aimed to estimate the prevalence of gastrointestinal nematodes and the intensity of infection in grazing dairy cattle from small and medium-sized farms in southern Poland. The level of antibodies against Ostertagia ostertagi in the bulk tank milk (BTM) from the animals was also assessed. Rectal fecal samples collected from 361 cows on 20 farms were examined using Willis-Schlaaf flotation and the McMaster method. BTM samples were tested for the presence of O. ostertagi antibodies using ELISA. Multiplex PCR was used to identify the third-stage larvae (L3) of gastrointestinal nematodes derived from the culture of pooled fecal samples from sampled farms. Gastrointestinal nematode eggs were found in the samples from 18 of the 20 herds with a prevalence range from 20.4 to 94.5%. The average number of eggs excreted in the feces of the herds was 200 eggs per gram (EPG). Antibodies to O. ostertagi were found in 20 of the examined herds (100%), of which 6 had optical density ratios (ODR) greater than 0.5. PCR results showed the presence of three nematode species: Ostertagia ostertagi, Cooperia oncophora and Oesophagostomum radiatum.
Alpine goats, a cosmopolite breed, and Nera di Verzasca, an autochthonous breed, reared in a mountain ecosystem of Lombardy, northern Italy, were tested for the effect of gastrointestinal nematode-sustained natural infections on both yield and quality of their milk. The survey was based on to the hypothesis that high levels of gastrointestinal nematode infection might affect milk yield, milk quality and lactation period length, and that the animal breed might influence such an effects. Seventy-one adult goats reared in the same farm were used in the study. From February to September 2010, 37 Alpine and 34 Nera di Verzasca goats were sampled for milk and feces monthly. Milk quantity, fat and protein contents, and somatic cell counts (SCC) were determined. The gastrointestinal parasitic infections were evaluated by fecal egg count (EPG) and animals were ranked into five classes according to their mean EPG: Le0 (Level0): <100 EPG; Le1 (Level1): 101-200 EPG; Le2 (Level2): 201-600 EPG; Le3 (Level3): 601-1500 EPG; Le4 (Level4): >1500 EPG. EPG counts and infection prevalence showed a high variability in both breeds, however the mean EPG values in Alpine goats were higher more than twice in comparison with Nera di Verzasca. Milk yield decreased in both breeds as the infection level increased. It occurred when Alpine goats reached level 3 of EPG counts while no decrease was found in Nera di Verzasca goats before reaching EPG level 4. Protein and fat contents were influenced by breed, level of EPG and milking days. Nematode infection was found to affect SCC values only at greatest levels of EPG counts. The results supported a different host-parasite relationship in the two goat breeds. In fact, though a reduction in milk yield, protein and fat contents was observed in both breeds, Alpine goats were found to be weaker in contrasting the effects of gastrointestinal nematodes than the more resilient Nera di Verzasca. The results of this survey can contribute to develop proper strategies in controlling goat parasitism by exploiting resilient breeds and improving sustainable rearing of local breeds.
Preventive veterinary medicine, 2012
Enzyme-linked immunosorbent assays (ELISAs) have been used as a diagnostic tool to quantify levels of gastrointestinal nematodes in dairy cattle by measuring Ostertagia ostertagi antibodies in milk. Higher levels of O. ostertagi antibodies measured by ELISA methods, referred to as optical density ratios (ODRs), are associated with decreased milk production in dairy cattle. On-farm management practices (e.g. pasturing techniques and anthelmintic usage) can influence the exposure of cattle to nematode infections and the magnitude of acquired worm burdens. Additionally, environmental and climatic factors, such as land elevation and precipitation, may also influence the levels of gastrointestinal parasitism. This repeated cross-sectional study investigated the effect of farm management practices and surrounding environmental factors on bulk tank (BT) ODRs in herds from provinces across Canada, and further examined the potential effects of various anthelmintic treatment protocols on BT O...
Animals, 2021
Pasture-borne parasites adversely affect bovine health and productivity worldwide. In Europe, gastrointestinal nematodes, especially Ostertagia ostertagi, the liver fluke Fasciola hepatica and the lungworm Dictyocaulus viviparus represent the most important parasites of dairy cattle. The present study assessed exposure towards these parasites among 646 cattle herds in three parts of Germany during 2017–2019 via antibody detection in bulk tank milk (BTM). Overall, O. ostertagi levels indicative of production losses were detected in 41.2% (266/646; 95% confidence interval (CI): 37.4–45.1%) of BTM samples, while F. hepatica seroprevalence amounted to 14.9% (96/646; 95% CI: 12.2–17.9%). Only 2.3% (15/646; 95% CI: 1.4–3.9%) of samples were D. viviparus antibody-positive. Significantly lower O. ostertagi as well as F. hepatica seroprevalence was detected in dual-purpose breeds compared to high-performance breeds from the same region. Management factors related to parasite exposure include...
Veterinary Parasitology, 1997
The epidemiology of gastrointestinal helminth infections in beef cows and calves on pasture was studied in Belgium during the 1990 and 1992 grazing seasons. Weight gain, faecal egg counts, generic differentiation of infective larvae, serum pepsinogen levels, herbage larval counts and worm burdens of tracer calves were used as parameters. In Study 1 two groups of ten cows with their spring-born calves grazing on separate pastures (A and B) were monitored during the 1990 grazing season. Ostertagia ostertagi was the predominant species shed by cows and calves.