Worm burdens, acquired resistance and live weight gains in lambs during prolonged daily infections with Trichostrongylus colubriformis (Giles, 1892) Loos, 1905

Parasitology ◽  
1974 ◽  
Vol 69 (3) ◽  
pp. 315-327 ◽  
Author(s):  
S. N. Chiejina ◽  
M. M. H. Sewell
Keyword(s):  
Worm Burden ◽  
Clinical Symptoms ◽  
Acquired Resistance ◽  
Live Weight ◽  
Trichostrongylus Colubriformis ◽  
Irreversible Damage ◽  
Cure Reaction ◽  
Development Of Resistance ◽  
Weight Gains ◽  
Faecal Egg Counts

Three groups of lambs, aged 3, 5 and 6 months respectively, were infected daily with 5000 infective larvae of Trichostrongylus colubriformis for periods of 15–20 weeks. Some of the lambs also received a single challenge infection at the end of week 16. The course of the infections was monitored by means of faecal egg counts, measurement of live-weight gains and regular post mortem worm counts.There was an initial rapid increase in egg counts soon after patency, which was followed by an exponential fall in the counts in most lambs. This fall seemed to precede the expulsion of worms by a few weeks and was associated with reduced fecundity in the female worms. Furthermore, although the trend of the egg counts of some lambs suggested that a self-cure reaction had taken place, in a number of these lambs the low faecal egg counts did not reflect the size of their worm burden.Heavy worm burdens were usually associated with clinical symptoms of trichostrongylosis, including anorexia, diarrhoea and loss of weight. As the lambs developed resistance to reinfection and expelled their worm burden a rapid clinical recovery occurred, except in a few lambs which appeared to have suffered irreversible damage from the earlier heavy worm burden.The worm burden in most lambs appeared to be cumulative during the first 4–8 weeks before they developed a strong resistance to reinfection. There was considerable loss of the adult worm burden by 8–15 weeks after initial infection and some evidence of stunting in the remaining parasites.The immunological control of T. colubriformis infections in these lambs was achieved by means of the development of resistance to reinfection, inhibition of the ovulation of the female worms, stunting of adult worms and expulsion of adult worms by resistant lambs. These may be separate immune phenomena requiring different thresholds of parasitic material in individual animals, depending on their age, the rate and duration of infection and their innate ability to develop resistance to the parasite.

Immunological response of the hosts to Toxocara canis (Werner, 1782) infection I. Effect of superinfection on naturally infected puppies

Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 547-559 ◽  
Author(s):  
S. T. Fernando
Keyword(s):  
Worm Burden ◽  
Egg Production ◽  
Technical Assistance ◽  
Acquired Resistance ◽  
Immunological Response ◽  
Toxocara Canis ◽  
Cure Reaction ◽  
Second Stage ◽  
Large Numbers ◽  
The University

Superinfection of naturally infected puppies with large numbers of Toxocara canis eggs induced a self-cure reaction. There was a sharp fall in Toxocara egg output following superinfection in most of the puppies. In most, but not all the puppies, the existing worm burden was eliminated. Eliminated worms were full of fertile eggs, but, in the puppies in which egg production fell sharply without expulsion of the worm burden, egg production by the naturally acquired worms was suppressed only transiently.Antibody production, measured by the complement-fixation test, was directly related to resistance to superinfection but not to self-cure.Acquired resistance reduced the pathogenic effects of superinfection, and prevented development of the parasite beyond the second stage.It is a pleasure to thank Professor P. Seneviratna, University of Ceylon, for his constructive criticisms of the manuscript and the facilities provided.The writer thanks Mr W. G. Senaratne for technical assistance and typing of the manuscript.This work was carried out with a special research grant from the University of Ceylon.

Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite, Trichostrongylus colubriformis

1986 ◽  
Vol 55 (3) ◽  
pp. 593-602 ◽  
Author(s):  
D. P. Poppi ◽  
J. C. Macrae ◽  
A. Brewer ◽  
R. L. Coop
Keyword(s):  
Small Intestine ◽  
Primary Infection ◽  
Dry Matter ◽  
Intestinal Parasite ◽  
Live Weight ◽  
Trichostrongylus Colubriformis ◽  
Infected Control ◽  
Development Of Resistance ◽  
Series Of Experiments ◽  
Small Intestines

1. Ten 5-month-old lambs (29 (SE 1.2) kg), reared parasite-free and prepared with rumen duodenal and ileal cannulas, were paired and given rations of Ruminant Diet AA6 (90 g/kg live Weight0.75) by means of continuous feeders. From 6 months of age one of each pair was dosed daily with 2500 Trichostrongylus colubriformis larvae for 14 weeks. Untreated animals received the amount of ration consumed by their infected pair-mates the previous day.2. During three periods, ((1) the week before and the first 2 weeks of dosing with infected larvae, (2) during weeks 5–7 and (3) during weeks 11–13 of dosing) all lambs underwent a series of experiments to determine their nitrogen balance, the amounts of N leaving the small intestine, the amount of 51CrC13-labelled plasma protein leaking into the small intestines, and the disappearance of 35S-labelled bacteria from the small intestine.3. The infection caused varying degrees of feed refusal in all infected animals. As a result the values for N balance and for the flow of N at the ileum during the latter two periods were regressed against dry-matter intakes for each group in each period.4. The infection caused a reduction (P < 0.05) in N retention and increased (P < 0.05) flow of N at the ileum. The increase in N flow at the ileum of infected lambs was greater (P < 0.01) at weeks 11–13 of dosing (infected–control 3.6 g N/d (standard error of difference (SED) 0.57), P < 0.01) than at weeks 5–7 of dosing (infected–control 1.5 g N/d (SED 0.57), P < 0.05).5. There were no between-treatment or between-period differences in the disappearance of 35S-labelled bacteria from the small intestines of infected or control lambs, but the infection did cause an increase in plasma N leakage during both periods. During weeks 5–7 and 11–13, plasma N leakage in infected lambs was 1.1 g N/d (P < 0.01) and 1.7 g N/d (P = 0.056) respectively higher than that in the control lambs.6. A proportion of the endogenous secretions which enter the small intestine is likely to be resorbed before the ileum. It was calculated that to account for the extra non-ammonia-N (NAN) flow at the ileum up to 3–5 g NAN/d during weeks 5–7 of dosing and 15–20 g N/d during weeks 11–13 of dosing could have entered the small intestine as mucin and sloughed cells.7. The results seem to indicate that the nutritional penalty associated with the development of resistance to infection is greater than that associated with the primary infection.

The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights

1986 ◽  
Vol 43 (2) ◽  
pp. 211-223 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel ◽  
E. A. Hunter
Keyword(s):  
Weight Gain ◽  
Compensatory Growth ◽  
Live Weight ◽  
Food Level ◽  
Live Weight Gain ◽  
Subsequent Performance ◽  
Herbage Intake ◽  
Winter Food ◽  
Weight Gains ◽  
Winter Feeding

ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.

scholarly journals Aspiculuris tetraptera in wild Mus musculus. Age resistance and acquired immunity.

1976 ◽  
Vol 50 (3) ◽  
pp. 197-202 ◽  
Author(s):  
M. Behnke Jerzy
Keyword(s):  
Mus Musculus ◽  
Worm Burden ◽  
Acquired Resistance ◽  
Age Groups ◽  
Acquired Immunity ◽  
House Mice ◽  
Wild House Mice ◽  
The Mean ◽  
Aspiculuris Tetraptera

AbstractWild house mice, naturally infected with Aspiculuris tetraptera were segregated according to their weight into six age groups. The prevalence of infection and the mean worm burden of these mice were studied in the different age groups. The overall prevalence of infection was high (57% or more) in all the groups except the youngest. Mice acquired larvae soon after weaning; the highest larval burdens were reached in juvenile mice and the highest mature worm burdens, a group later, in mature mice. Older mice had fewer larvae and fewer mature worms. The mature worm burdens decreased but relatively slower than the larval burdens. It is suggested that either innate or acquired resistance could account for these observations.

An evaluation of beef carcass quality 1. The influence of cereal feeding on the growth and carcass quality of Friesian steers

1972 ◽  
Vol 15 (3) ◽  
pp. 215-227 ◽  
Author(s):  
C. E. Hinks ◽  
J. H. D. Prescott
Keyword(s):  
Meat Quality ◽  
Live Weight ◽  
Carcass Composition ◽  
Factorial Experiment ◽  
Carcass Quality ◽  
Grazing Cattle ◽  
Weight Gains ◽  
Second Period ◽  
Tasting Panel

SUMMARYTwenty-four Friesian steers, initially 5 months of age, were involved in a 2 × 2 factorial experiment which spanned grazing and silage feeding periods of 22 weeks' duration. In the first period, cattle were stocked at a uniformly high density, with half of the group being fed 1·25 kg/head per day of supplementary barley. In the second period, the cattle were subdivided into four groups and fed varying levels of barley with silage. Finally all the animals received 3·65 kg/head per day of barley. Replicates of the four treatments were slaughtered at random after 5 to 11 weeks on this treatment. Whilst supplementary cereal feeding significantly increased the live-weight gains of steers at grass by 11%, this live-weight advantage was offset by their slower gains in the final weeks before slaughter. Feeding cereals to grazing cattle had little effect on carcass composition or the proportions of carcass joints, but their beef was considered, by a tasting panel, to be more tender than the meat from the control steers.Increasing the level of barley fed with silage only increased live-weight gains by 2%, and had little effect on carcass or meat quality.

scholarly journals TUBERCULOSIS OF RABBITS INDUCED BY DROPLET NUCLEI INFECTION

1948 ◽  
Vol 87 (6) ◽  
pp. 585-594 ◽  
Author(s):  
H. L. Ratcliffe ◽  
W. F. Wells
Keyword(s):  
Inflammatory Response ◽  
Linear Relationship ◽  
Normal Control ◽  
Acquired Resistance ◽  
Single Exposure ◽  
Initial Infection ◽  
Development Of Resistance ◽  
Droplet Nuclei ◽  
Initial Lesions

At intervals from 2 to 11 weeks after normal rabbits had inhaled small numbers of virulent bovine tubercle bacilli as separated cells in droplet nuclei, groups of these animals received a single exposure to reinfection during which each animal inhaled about 20,000 separated bacilli. Normal control rabbits which inhaled this large number of bacilli died within 4 weeks thereafter. Their deaths were attributed to destruction of the lungs by developing initial tubercles. Eleven of 12 rabbits which were reinfected within 4 weeks after initial infection seemed to respond as normal animals. Their lungs were largely replaced by developing reinfection tubercles when they died or were killed within 32 days after reinfection. The inflammatory response of the reinfection tubercles was not consistently different from that of initial tubercles, although reinfection tubercles contained fewer bacilli than initial lesions of the same age. Within 5 weeks after initial infection rabbits apparently had developed immunity to reinfection with virulent bovine tubercle bacilli inhaled as separated cells in droplet nuclei. In some of them, however, exposure to massive inhaled reinfection seemed to stimulate the progress of initial infection. It is suggested that in rabbits the development of resistance to tubercle bacilli does not bear a linear relationship to time, but progresses in steps and within 5 weeks after small initial infection by inhalation is adequate to prevent the growth of separated bacilli when these are deposited upon alveolar walls. It is suggested also that the basic effect of acquired resistance of rabbits to tubercle bacilli is inhibition of multiplication of the bacilli.

Effects of nutrition in late pregnancy on subsequent milk production in Ewes

1970 ◽  
Vol 12 (1) ◽  
pp. 23-36 ◽  
Author(s):  
T. T. Treacher
Keyword(s):  
Milk Production ◽  
Dry Matter ◽  
Live Weight ◽  
Late Pregnancy ◽  
Lower Content ◽  
Weight Changes ◽  
Total Birth ◽  
Weight Gains ◽  
Ad Libitum ◽  
Voluntary Intake

SUMMARY1. Scottish Half-bred ewes carrying twin foetuses were fed individually to make live-weight gains in the last six weeks of pregnancy of (1) 20%, (2) 10% and (3) 0% of their live weight in week 14 of pregnancy. In lactation the ewes were fed ad libitum. The lambs were removed 12 to 16 hr after parturition and the ewes were machine-milked twice daily for the first six weeks of lactation.2. Total birth weights per ewe of twin lambs from the treatments were (1) 10·10 kg, (2) 9·44 kg and (3) 8·18 kg and differed significantly.3. The level and pattern of voluntary intake in lactation did not differ significantly between the treatments. Total dry-matter intakes in the six weeks of lactation were (1) 121·9 kg (2) 105·9 kg and (3) 109·5 kg.4. The pregnancy treatments affected the level of milk production and the shape of lactation curves. The total yields in the first six weeks of lactation were (1) 58·8 kg, (2) 43·5 kg and (3) 26·9 kg. Higher contents of fat and protein and the lower content of lactose in the milk from treatment-3 ewes on days 1 and 3 of lactation indicated a slower onset of lactation in these ewes. Between days 7 and 35 of lactation the contents of fat and SNF were lowest on treatment 3 but the differences were not significant.5. The live-weight changes in lactation, which were in inverse order to the gains in late pregnancy, were (1) 3·4 kg, (2) 5·5 kg and (3) 9·5 kg.

scholarly journals Effect of inorganic and organic zinc supplementation on coccidial infections in goat kids

2011 ◽  
Vol 80 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Petra Strnadová ◽  
Vlasta Svobodová ◽  
Leoš Pavlata ◽  
Ľubica Mišurová ◽  
Rudolf Dvořák
Keyword(s):  
Zinc Oxide ◽  
Plasma Concentration ◽  
Blood Plasma ◽  
Clinical Symptoms ◽  
Clinical Signs ◽  
Control Group ◽  
Organic Zinc ◽  
Highest Weight ◽  
Weight Gains ◽  
Zinc Concentrations

The aim of this study was to identify the effect of zinc-enriched diet fed to goats and their kids on the number of Coccidia oocysts shed by kids, on clinical signs of coccidiosis, weight gains, and kids’ blood plasma concentration of zinc. A total of 22 goat kids were divided into 4 groups of 5 or 6 animals. Goats and kids from the control group did not receive any additional zinc, the second group was supplemented with inorganic zinc (zinc oxide), the third group was given zinc lactate, and the fourth group received chelated zinc. Samples of kids’ faeces were taken weekly from 3 to 9 weeks of their age (a total of 7 samples were taken). Samples of faeces were examined by a quantitative method to detect the number of oocysts. Kids were weighed weekly and their blood was taken in order to determine zinc concentrations in blood plasma. Animals from the group supplemented with zinc chelate and zinc lactate shed a significantly (p ≤ 0.05) lower number of oocysts (13.4% and 11.9%, respectively) compared to the number of oocyst shed by control and zinc oxide supplemented groups (25% and 49.7%, respectively). Shedding of oocysts was not accompanied by clinical symptoms of coccidiosis in any of the groups. Kids supplemented with zinc chelate showed significantly highest weight gains and blood plasma concentration of zinc (p ≤ 0.05) as compared to control and inorganic zinc supplemented groups. Organic zinc is to be recommended to be used as a prophylaxis against coccidiosis in goat kids.

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