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1.
Faye D Osaer S Goossens B Van Winghem J Dorny P Lejon V Losson B Geerts S 《Veterinary parasitology》2002,108(2):117-136
Forty pure West African Dwarf (WAD) goats and 35 of its F1 crosses with the Sahelian breed were used in a multifactorial experimental design to evaluate the effects of an experimental Trypanosoma congolense infection and interactions with natural helminth infections and different levels of diet on health and productivity of these two breeds. Trypanosome infection caused a severe drop in packed cell volume (PCV), but this was not significantly affected by breed. Neither deworming nor diet had any effect on the course of anaemia after trypanosome infection. The mean score of parasitaemia tended to be higher in crossbreeds than in WAD goats although this was not significant (P>0.05). Similarly, the antibody response to trypanosome infection was not significantly different between breeds. Parasitaemia level was significantly influenced by the level of diet with the group under high supplementation having a higher mean parasitaemia score than the group under low supplementation. Weight loss due to trypanosome infection tended to be greater in crossbreeds than in WAD goats (P>0.05).During this study, there was no difference in mean helminth egg output between crossbred and WAD goats. However, between weeks 4 and 10 after trypanosome infection (corresponding to a period of heavy rainfall and highly infective pastures), the mean egg output was higher in the crossbreeds.The immunosuppressive effect of trypanosome infections was revealed by a lower antibody response to Haemonchus contortus in infected animals compared to the uninfected controls. Trypanosome infection tended to increase strongyle egg output. This study did no reveal any superior trypanotolerance of WAD goats compared to crossbreeds. 相似文献
2.
Fakae BB Musongong GA Chiejina SN Behnke JM Ngongeh LA Wakelin D 《Veterinary parasitology》2004,122(1):51-65
The West African Dwarf (WAD) goat is known to be relatively resistant to infection with Haemonchus contortus. An experiment was carried out to assess variability in resistance under escalating trickle and single pulse challenge infection protocols. Thirty two 7-8 month old goats were subjected to trickle infection beginning with a thrice weekly dose of 100 L3 and increasing to 500 L3 by week 5, the last dose being administered on D30. Infection was abbreviated with fenbendazole on D32 and the animals challenged with 4000 L3 (=404-741L3/kg body weight) on D46 and necropsied on D81. The goats exhibited marked individual variability in faecal egg counts (FEC) and worm burdens (Wb). For convenience, we arranged the goats into FEC classes 1, 2 and 3, corresponding to peak counts of <1000, 1000-2500 and >2500 epg and Wb classes 1, 2 and 3, with counts of <50, 50-100 and >100 worms, respectively, broadly reflecting relatively resistant, intermediate and poorly resistant response phenotypes. Wb classes broadly reflected the FEC phenotypes and although there were no significant differences between the Wb of the FEC classes at necropsy, significant differences in FEC were detected when analysis was carried out only on Wb classes. There was also a significant positive correlation between FEC class on each of the days of challenge (D67 to D80) and worm burden at necropsy. In general, the goats showed strong resistance/tolerance to challenge, with more than 80% having Wb not exceeding 5% of the challenge dose, and only in class three goats were weight loss and anaemia detected in some animals. PCV and weight changes also closely reflected the FEC and Wb classes, with a significant negative correlation between each and Wb. Infection level did not significantly affect the sizes of either male or female worms and no significant difference was detected between the levels of circulating eosinophils in any FEC or Wb class. Overall, the data are consistent with the existence of a range of response phenotypes, which reflect variations in resistance of WAD goats to H. contortus infection, the genetic basis of which will be explored in future experiments. 相似文献
3.
S N Chiejina B B Fakae J M Behnke P A Nnadi G A Musongong D Wakelin 《Veterinary parasitology》2002,104(3):229-242
The capacity of young Nigerian West African Dwarf (WAD) goats to express good acquired immunity to their native geographic strain of Haemonchus contortus and the correlates of this responsiveness were studied in a laboratory experiment involving forty 7-8 month old kids. A primary immunising infection with 2000 L3 (equivalent to 260-450 L3/kg body weight) with or without challenge on D42 with 2000 L3 resulted in a mild chronic infection with a pre-patent period of 18-20 days and little or no reduction in worm burden between D14 and D56. In contrast, another group (D) of kids, whose immunising infection had been truncated with fenbendazole on D35 and later received similar challenge infection, developed good protection against challenge. Thus, worm burdens were largest in group E (challenge control), larger in group C (primary+challenge) and least in group D. Of the measures of infection used, namely faecal worm egg counts (FECs), circulating eosinophil (EOS) responses, packed cell volume (PCV) and body weight, FEC and EOS responses exhibited marked individual variability, but only FEC (geometric mean of transformed counts) and PCV showed strong correlation with worm burden. There was also a significant negative correlation between FEC and PCV. The size of inoculum used was well tolerated by the kids, as it induced only mild changes in PCV in some goats and no effect at all on body weights. This suggests that the WAD goat may possess a good measure of resistance to the pathogenic effects of its native strain of H. contortus. The wide individual variability in FEC and its strong relationships to worm burden and PCV are pointers to its likely genetic basis. There are, therefore, good prospects for further studies to identify H. contortus resistant genotypes among the WAD goat population. 相似文献
4.
Behnke JM Chiejina SN Musongong GA Fakae BB Ezeokonkwo RC Nnadi PA Ngongeh LA Jean EN Wakelin D 《Veterinary parasitology》2006,141(1-2):107-121
West African Dwarf (WAD) goats of the Nigerian subhumid zone generally show strong resistance and resilience to Haemonchus contortus in laboratory experiments, although a relatively small proportion are susceptible to infection. Little is known about these extremes of response phenotype in nature. Therefore, a survey was carried out of gastrointestinal nematode infections in WAD goats, with emphasis on abomasal worms, at three goat markets in Southern Nigeria during the rainy season. Faecal samples (n=1070) were collected weekly from goats between April and September, and 352 abomasa and small intestines from local abattoirs were examined. Total strongyle (prevalence=65.0%) and H. contortus (prevalence=64.3%) faecal egg counts (FEC) varied between the three markets, being highest throughout at Opi. FEC increased from April to peak in August. Based on raw FEC, 76.1% of goats had FEC of <100, and 4.7%>500. Adjustment of these figures for monthly and between-market differences, gave figures of 78.8 and 3.4%, respectively. H. contortus worm burdens (WB) showed a similar pattern with 67.9% of goats harbouring <200 worms and 8.2% >1000, and after adjustment 69.6 and 6.0%, respectively. Fecundity, based on eggs in the uterus, did not vary between markets or monthly, but fell with increasing WB. Trichostrongylus colubriformis was less frequent (prevalence=42.4%) but goats from Opi also carried higher WB, and worms were similarly highly aggregated in hosts. When the between-market and monthly differences for both species were controlled, a highly significant positive correlation between the species emerged. Therefore, although a small subset of goats, highly susceptible to H. contortus, exists in this breed, the majority show resistance under field conditions and the resistant phenotype is also resistant to T. colubriformis. Both species are highly aggregated in the susceptible subset of the population. While, we cannot yet exclude alternative explanations, our data are compatible with a strong genetic basis for this phenomenon. 相似文献
5.
Dhollander S Bos J Kora S Sanneh M Gaye M Leak S Berkvens D Geerts S 《Veterinary parasitology》2005,130(1-2):1-8
West African Dwarf goats (WADs) and their Saanen crosses were experimentally infected with Trypanosoma congolense. No significant differences were found between trypanosome parasitaemia and antibody response of the crossbred and WAD goats. Neither the WAD goats nor the Saanen crosses were able to control the drop in PCV following trypanosome infection. The level of anaemia caused by the trypanosome infection was similar in the two breeds during the trial. Based on these findings, no difference in tolerance or susceptibility to T. congolense could be demonstrated between the WAD goats and their Saanen crosses. Although the weight of all goats increased during the trial, the crosses gained significantly more weight than the WAD goats. The trypanosome infection reduced the growth rate of both breeds, but this reduction was not statistically significant. Crossbreeding trypanotolerant WADs with trypanosusceptible Saanen goats might, therefore, be an effective means of increasing productivity. 相似文献
6.
Joshi BR Kommuru DS Terrill TH Mosjidis JA Burke JM Shakya KP Miller JE 《Veterinary parasitology》2011,178(1-2):192-197
Effect of sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don.] leaf meal feeding was evaluated in two experiments in indoor reared goats with experimental infection of Haemonchus contortus larvae. In the first experiment, ten 8-10 month old male Spanish and Alpine cross kids pair matched for body weight and age were fed SL or bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay one week before infection and were infected with 5000 H. contortus L(3). The animals were maintained on the same diet for the remaining period and were slaughtered 28 days post-infection (DPI) to determine the establishment of incoming infective larvae. Goats fed SL had lower establishment (P<0.05) of H. contortus larvae than that of the control goats fed BG hay. In the second experiment, twenty-five 8-10 months old male Alpine cross, Saanen, Nubian×Saanen and Spanish kids reared in confinement on BG were experimentally infected with 5000 H. contortus L(3). On 35 DPI, the animals were allocated to two groups after blocking by fecal egg count (FEC), and one group was fed SL leaf meal (n=13), and another control group remained on BG (n=12). Four goats/group were slaughtered successively on days 7, 14, and 28 days post SL feeding, except on day 7, when five SL fed goats were slaughtered. Fecal egg counts and blood packed cell volume (PCV) were measured at weekly intervals and worm count, female worm fecundity, worm length and mucosal eosinophils, mast cells and globule leucocytes were measured after slaughter. Goats fed SL had a lower FEC (P<0.05) one week after feeding, as compared to those fed on BG, and the values remained at low level thereafter. Similarly, PCV was also significantly affected by feeding (P<0.01), and feeding and time interaction (P<0.05). However, worm burden, female worm fecundity, parasite length, and mucosal inflammatory cell count were similar between the groups. Feeding SL reduced the establishment of infective larvae and FEC of H. contortus in experimental studies and this plant could be used for biological control of parasite infection under field conditions to limit the harmful effects of the parasites in goats. 相似文献
7.
Trypanosome infections, packed red cell volume levels (PCV), body weight and nematode faecal egg counts of village-based small ruminants were monitored in two areas in The Gambia with either moderate or high trypanosomosis risk for 24 and 30 months respectively. Outflows from the flock and new-born animals were recorded and data on housing and management were compiled. Reported mortality rates were higher in goats than in sheep, but for both species highest in the moderate risk area. The peak of trypanosome infections lagged the peak of tsetse densities by 1-3 months in both areas. Trypanosoma vivax was the predominant species found in the infected animals, followed by T. congolense. Trypanosome prevalence was, in general, higher in sheep than in goats but only significantly higher during Year 1 in the moderate risk area. Trypanosome infection reduced the PCV level significantly and seasonal effects indicated significantly lower PCV levels during the rains. Trypanosome infection significantly depressed weight gain in both species at periods where infection rates were highest. In both species considerably lower weight gains were observed during the rainy season. Abortion rates were higher in goats than in sheep in both study sites, and highest in the high-risk site. Trypanosome infection in ewes in the high risk area increased lamb mortality significantly but had no effect on birth weights, nor on growth rates up to 4 months. Offspring mortality up to 4 months was generally high at both sites. Trypanosome infection in the dam between 3.5 to 7 months post parturition significantly increased parturition interval in both species. Peak faecal egg output occurred at the end of the rainy season and was highest for both species in the moderate risk site. Poor grazing management was found responsible for a seasonal nutritional constraint. Based on these results, these breeds of sheep and goats can be considered as trypanotolerant since they are able to remain productive under high and moderate levels of trypanosome challenge. Nevertheless, trypanosomosis affected their health and production level as shown by reduced PCV levels, depressed weight gains, longer parturition intervals and higher lamb mortality. In addition, during the rains, helminth infections and poor management leading to nutritional constraints had also a negative impact on health and production and therefore influenced the innate resilience to trypanosomosis in those indigenous breeds. Adaptations in management may have an equal impact as certain disease control measures to improve biological and economical returns from small ruminants in tsetse infested rural areas. 相似文献
8.
de la Chevrotière C Bambou JC Arquet R Jacquiet P Mandonnet N 《Veterinary parasitology》2012,186(3-4):337-343
Small ruminants are affected by gastrointestinal nematode (GIN) infection. A promising alternative strategy for control of GIN infection is to increase the level of resistance in the population by taking advantage of the host's immune response. Immunoglobulin A (IgA) and E (IgE) are known to be involved in immune response to GIN. The aim of this study was thus to investigate genetic parameters of IgA and IgE responses against Haemonchus contortus in Creole kids naturally challenged at pasture and to determine the relationship with other resistance criteria such as faecal egg counts, packed-cell volume, eosinophil counts and bodyweight. Variance and covariance components for genetic and residuals effects for each trait were estimated on 3862 males at 11 months of age. Heritability estimates for IgA and IgE ranged between 0.15 and 0.57. Strong positive genetic correlations were observed between either IgE or IgA responses against L3 and adult excretory/secretory products (ESP) antigens of H. contortus, suggesting that the humoral immune response is not specific to the life cycle stage of the parasite suggesting that there is substantial cross recognition between the different parasite antigens. Heritability estimates for faecal egg count (FEC), packed-cell volume (PCV) and bodyweight (BW) were in accordance with previous results in Creole kids. Blood eosinophil counts were found moderately heritable and negatively correlated with FEC, suggesting that this cell population plays a role in resistance to nematode parasite infection in Creole goats. IgA response was positively correlated to FEC, in contrast with the negative correlation between IgE against L3 of H. contortus and FEC. In Creole goats, IgA response against L3 or ESP of H. contortus would rather be associated with the worm burden than an immune protective response. The immune response involving activity of IgE against L3 of H. contortus may be one important pathway for development of resistance to gastrointestinal nematode infections in Creole goats. 相似文献
9.
Shaik SA Terrill TH Miller JE Kouakou B Kannan G Kaplan RM Burke JM Mosjidis JA 《Veterinary parasitology》2006,139(1-3):150-157
Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, is the biggest constraint to profitable goat production in the United States (US). Due to widespread prevalence of anthelmintic resistance in goat GIN, alternative, non-chemical control methodologies are needed to increase profitability of small ruminant industries. A study was designed to test the efficacy of a high condensed tannin (CT) legume, sericea lespedeza [SL, Lespedeza cuneata (Dum.-Cours. G. Don)] against GIN of goats fed in confinement. The goats were given a trickle infection of 500 H. contortus larvae/animal three times per week during the trial to simulate natural infection. Twenty Boer bucks (6-8 months old) were fed bermudagrass [BG, Cynodon dactylon (L.) Pers.] hay plus concentrate for 5 weeks in confinement and then 10 animals were switched to SL hay for an additional 7 weeks. Throughout the trial, feces and blood were collected weekly from individual animals to determine fecal egg count (FEC) and blood packed cell volume (PCV). Fecal cultures were made weekly from pooled samples to determine treatment effects on GIN larval development. All goats were slaughtered at the end of the trial, with adult worms in the abomasum and small intestine of each goat recovered, counted, and identified to species. Feeding SL hay to goats significantly (P<0.01) reduced FEC and increased PCV compared with BG hay. In addition, a lower percentage of ova in feces from SL-fed goats developed into infective (L3) larvae. There was a direct effect of SL hay on adult worms, with significantly (P<0.01) lower numbers of both abomasal (H. contortus, Teladorsagia circumcincta) and small intestinal (Trichostrongylus colubriformis) nematodes compared with goats fed BG hay. Feeding SL hay to goats is an effective means of controlling parasitic nematodes and may be a potential supplement/replacement for chemical anthelmintics. 相似文献
10.
The objectives of these experiments were to determine the optimal dose of copper oxide wire particles (COWP) necessary to reduce gastrointestinal nematode (GIN) infection in young and mature goats naturally infected with Haemonchus contortus or a mixed infection and to determine whether the effectiveness could be enhanced through feeding management. Two experiments were conducted during cooler months in Georgia, and 4 experiments were conducted during warmer spring or summer months in Arkansas. Meat goats received 0 up to 10 g of COWP under a variety of management conditions. In all experiments, blood and feces were collected every 3 or 7 d from 6 to 42 d to determine blood packed cell volume (PCV) and fecal egg counts (FEC) to estimate the degree of GIN infection. In mature goats grazing fall pasture, mean FEC of 0 g of COWP-treated goats increased, and those of 4 g of COWP-treated goats remained low on d 0, 7, and 14 (COWP x d, P < 0.03), and FEC decreased on these days (P < 0.001). In 5 and 10 g of COWP-treated goats, PCV increased (P < 0.001), but FEC and PCV remained unchanged over time in control goats. Fecal egg counts were similar among all low doses (0.5, 1, 2, 4 g) of COWP administered to weaned kids for all dates examined (P > 0.10), which were lower on d 7 through 21 (COWP x date, P < 0.05) but similar by d 28, compared with FEC of 0 g of COWP-treated kids. Packed cell volume was lower in 0 g compared with all COWP-treated kids by d 14 (COWP x date, P < 0.05). Feeding management in combination with COWP for GIN control had little effect compared with COWP alone for these short-term studies. In conclusion, a dose of COWP as low as 0.5 g, which was considered optimal to reduce the risk of copper toxicity, was effective in reducing FEC in young goats, and 5 g of COWP was effective in older goats. Copper oxide does not appear to be effective in controlling newly acquired L4 stage (preadult) larvae, which also feed on blood, leading to decreased PCV in newly infected goats. 相似文献
11.
The objective of the experiment was to determine the optimal dose of copper oxide wire particles (COWPs) to reduce infection of Haemonchus contortus in male lambs. Five to six-month-old hair breed lambs were housed on concrete and fed 450 (L; n = 25) or 675 g (H; n = 25) corn/soybean meal supplement and bermudagrass hay. In July, lambs were inoculated with 10,000 L(3) larvae (97% H. contortus; Day 0). Lambs were administered 0, 2, 4, or 6 g COWP on Day 28. Concentrations of copper in the liver were determined. There were no effects of supplement level on concentrations of copper in the liver and a linear relationship existed between COWP treatment and concentrations of copper in liver (P < 0.001). Least squares means of the 0, 2, 4, 6 g COWP treatments were 62.2, 135.7, 161.1, and 208.4 ppm (P < 0.001). Between Days 0 and 28, PCV declined and by Day 42, PCV of all COWP-treated lambs was markedly higher than control lambs and remained higher (COWP x day, P < 0.05). By Day 21, PCV was greater in the H compared with the L group of lambs (P < 0.001). Within 14 days of COWP treatment FEC declined from more than 8000 eggs/g (epg) to less than 250 epg in all COWP-treated lambs (COWP x day, P < 0.001). The numbers of H. contortus in the abomasum were greatly reduced in all COWP-treated groups of lambs and remaining nematodes were predominantly males. FEC were greater in L versus H supplemented lambs and values decreased to a greater extent in H lambs when treated with COWP (supplement x COWP; P < 0.02). The 2 g COWP was effective in alleviating H. contortus infection and reducing number of egg-laying nematodes in the abomasum with the lowest concentration of copper in the liver of the COWP treatment groups. PCV values were more favorable for lambs fed the higher level of supplement, especially when FEC were greater than 8000 epg. 相似文献
12.
Mandonnet N Bachand M Mahieu M Arquet R Baudron F Abinne-Molza L Varo H Aumont G 《Veterinary parasitology》2005,134(3-4):249-259
The control of gastrointestinal nematodes requires an understanding of their epidemiology so that particular parasite stages can be targeted. Dam infection during early lactation is one example of this in ruminant nematode infections. The existence of the peri-parturient relaxation in immunity and its impact on productivity were examined in a Creole goat flock from Guadeloupe, exposed to mixed natural infection (predominantly Haemonchus contortus and Trichostrongylus colubriformis). A total of 1,511 l were obtained from 909 does resulting from 463 dams and 150 sires. Fecal and blood samples were collected at kidding before anthelmintic drenching, 4 and 6 weeks after kidding. The traits analyzed were logarithm transformed fecal egg counts (FEC), packed cell volume (PCV), and logarithm transformed blood eosinophilia counts (EOS) for does at each sampling point and changes in these during the postpartum period. With the exception of the PCV values measured at kidding, lactating does had significantly higher FEC and lower PCV than control dry does at every sampling point. Geometric means of FEC in lactating does were 819 +/- 174, 677 +/- 146 and, 699 +/- 160 eggs per gram (EPG) at kidding, 4 and 6 weeks after kidding respectively. Geometric means of FEC in dry does were 187 +/- 57, 89 +/- 28, 133 +/- 43 at these time points, respectively. EOS differences were not consistent between groups and probably not specific enough for variations in Creole goats' peri-parturient rise to be discussed. As does aged, their egg output decreased and primiparous does always had greater egg output than multiparous ones. Overall, does' FEC at 4 weeks after kidding decreased by 1.3% each year. The higher the litter size, the higher the FEC at kidding and inverse applied for PCV measurements. Does that stopped lactating had significantly lower FEC and higher PCV values than lactating does with low milk yields. Higher infection rates during early lactation in Creole goats were recorded in does with lower maternal ability assessed by the average daily weight gain of kids between 10 and 30 days of age. Kids from dams with higher FEC (i.e. >600 EPG higher than corresponding does) had 17% lower average daily weight gain between 30 and 70 days postpartum and were approximately 1 kg lighter at weaning than kids from dams with lower FEC. Thus, it is clear that a peri-parturient rise in FEC exists in Creole goats. By controlling the intensity of this peri-parturient rise in FEC, herd health and productivity could be substantially improved. 相似文献
13.
Arrested development of Haemonchus, Cooperia and Trichostrongylus spp. was studied in (1) 14 naturally infected and eight experimentally infected West African Dwarf (WAD) goats reared in the derived savanna zone of eastern Nigeria and (2) 55 naturally infected slaughter goats obtained from the savanna and sahel regions of northern Nigeria. Six of the WAD goats carried natural infections of H. contortus and T. colubriformis and eight other (tracer) goats acquired their infections from a grass paddock artificially contaminated with H. placei, C. pectinata and C. punctata, during May to October. Another three WAD goats were artificially infected with mixed cultures of L3 of the latter three nematodes, while five goats were inoculated with 1500-2000 L3 of H. contortus harvested from cultures incubated at 25-30 degrees C for 8 days either in the dark or under normal laboratory conditions. Approximately 41% (9/22) of the infected WAD goats harboured arrested larvae of Haemonchus and/or Cooperia. No arrested larvae of Trichostrongylus were found in the six animals that were infected with this nematode. The level of inhibition varied from 0.4 to 20% and only three animals showed greater than 10% inhibition. This very low level of inhibition occurred in naturally and experimentally acquired infections, irrespective of the time of year. In the case of Haemonchus, the species and strain of the parasite and infection with L3 cultured in the dark also appeared not to influence the level of inhibition. By contrast, 65.5% (36/55) and 5.5% (3/55) of the northern savanna and sahel goats harboured arrested larvae of H. contortus and T. colubriformis, respectively. The mean percentage inhibition of the former was low (2-25%) during most of the rainy season (June-August) and high (75-90%) during the late rains and the dry season (October-April). The lowest and highest mean percentage inhibitions occurred during July and November, respectively. 相似文献
14.
This study describes responses to artificial infection with Haemonchus contortus in ewes and lambs of 50% Dorset, 25% Rambouillet, and 25% Finn-sheep ancestry and provides estimates of genetic parameters for measures of parasite resistance. One hundred ninety-eight ewes out of 64 sires, and 386 lambs out of 25 sires were evaluated in autumn and spring of 2 yr. Ewes were dewormed shortly after weaning their lambs and lambs were dewormed at about 120 d of age. One week after deworming, ewes and lambs were dosed with approximately 10,000 infective larvae of H. contortus. After infection, BW, fecal egg counts (FEC), and packed cell volume (PCV) were measured weekly for 7 wk in lambs kept in drylot and fortnightly for 11 wk in ewes on pasture. Summary traits were defined as initial PCV, mean BW across all times, and means for PCV (MPCV) and log-transformed FEC (MLFEC) at wk 3 to 7 after infection for lambs and wk 3 to 11 after infection for ewes. Ewes and lambs did not lose weight overall in any year or season, but there was no consistent effect of year or lambing season on mean LFEC or mean PCV during infection in either ewes or lambs. Yearling ewes were less resistant to infection than older ewes, with lower PCV (P < 0.05) and higher LFEC (P < 0.05). During infection, PCV was positively correlated with BW and negatively correlated with LFEC in both ewes and lambs. In lambs, heritabilities were 0.39 (P < 0.01) for PCV, 0.10 (P < 0.05) for LFEC across all measurement times, and 0.19 (P < 0.01) for three measures of LFEC taken at the peak of infection. Heritability estimates for ewes were 0.15 (P < 0.05) for PCV and 0.31 (P < 0.01) for LFEC. Repeatabilities for LFEC and PCV across measurement times were moderate in ewes and lambs. Correlations between dam and lamb records for MLFEC were generally low, suggesting different mechanisms of resistance in lambs and nonlactating ewes. Ewes with higher genetic merit for growth as lambs were less resistant to infection as adults, but genetic merit for fertility and prolificacy were not related to parasite resistance. Lambs with higher genetic merit for body weight were more resistant to infection. Selection for resistance to H. contortus is therefore possible and should not adversely affect growth of lambs and fertility of ewes in this production environment. 相似文献
15.
Burke JM Whitley NC Pollard DA Miller JE Terrill TH Moulton KE Mosjidis JA 《Veterinary parasitology》2011,181(2-4):345-349
The objective of three experiments was to determine the impact of supplementing sericea lespedeza (Lespedeza cuneata; SL) in three concentrations in a loose or pelleted diet on gastrointestinal nematodes (GIN) in small ruminants. Experiments on lambs were conducted at the USDA, Agricultural Research Service in Booneville, AR (Exp. 1) and at Louisiana State University in Baton Rouge, LA (Exp. 2); an experiment on goat kids occurred at University of Maryland-Eastern Shore (Exp. 3). Exp. 1 used crossbred hair sheep lambs naturally infected with GIN that were randomly allocated to diets containing 0, 25, 50, and 75% SL diets (n=11 or 12/diet). Exp. 2 consisted of Haemonchus contortus-inoculated crossbred wool breed lambs that were blocked by gender and FEC and randomly assigned to 0, 25, 50, or 75% SL diet (n=8/diet). Fecal egg counts (FEC) and blood packed cell volume (PCV) were not influenced by SL supplementation in Exp. 1 and 2. Exp. 3 consisted of naturally GIN infected Boer crossbred goat kids in individual pens. Kids were blocked by FEC and randomly allotted to treatments of 0, 20, 40, or 60% SL with 9-13 goats/diet. The more SL fed, the greater the reduction in FEC (P<0.001). There was an increase in PCV in SL fed goats (P<0.001). Larval speciation at the end of the experiment indicated that feces from control animals produced 43% H. contortus larva while 20, 40 and 60% SL resulted in 39%, 35% and 31% H. contortus larvae, respectively. Feeding dried SL may be less effective in lambs than kids, though concurrent studies must be conducted to confirm this. 相似文献
16.
The present study examined the development of anaemia in Small East African goats experimentally infected with Trypanosoma congolense or Trypanosoma brucei. Experimental goats received a primary trypanosome challenge on day 0, treated with diminazene aceturate on day 49 and received a secondary trypanosome challenge on day 77 of the 136-day experiment. Both primary and secondary challenges were characterised by reduced peripheral erythrocyte counts, fall in packed cell volume (PCV), hypohaemoglobinaemia and reductions in the myeloid:erythroid ratios (M:E) compared with the uninfected goats. The progressive reduction in the M:E ratios denoted increased erythrogenesis in response to increased destruction of erythrocytes in blood by infecting trypanosomes or their products. The more rapid fall in M:E ratio in T. congolense infections shows that this parasite causes more severe clinical pathological effects in goats than T. brucei. 相似文献
17.
The effect of dietary protein on the pathophysiology of Haemonchus contortus infection in reproducing first pregnancy West African Dwarf (WAD) goats was studied. Eighteen 10-12-month-old pubertal female WAD goats divided into two equal groups were used and confined separately. One group was maintained on high-protein diet (HPD) while the other was maintained on low-protein diet (LPD) from day 1 of pregnancy up to week 6 post-partum. Each animal was infected with 600 infective larvae of H. contortus weekly for 4 weeks and blood collected by jugular venipuncture for the determination of packed cell volume and serum proteins. The results of the study showed that improved protein nutrition significantly enhanced the level of serum albumin (p<0.05). It also significantly lowered the level of serum globulin (p<0.05) that otherwise would be high in haemonchosis. However, improvement in the dietary protein level appeared not to have any effect on the packed cell volume and total serum protein level. 相似文献
18.
19.
Copper oxide wire particles (COWP) have been used to reduce infection of Haemonchus contortus in hair breed lambs in southeastern USA without signs of copper toxicity. However, copper sensitivity among breeds and regions varies. The objective was to determine the effectiveness and safety of COWP in lactating Polypay ewes and their offspring grazing alfalfa/bluegrass pasture in a rotational grazing system. Mature Polypay ewes were administered 0, 0.5, 1, or 2 g (n=8 or 9/dose) COWP approximately 60 days after lambing in mid-July 2005. Their offspring were administered 0 (n=6), 0.5 or 0.75 g (n=9), 1 or 2 g (n=6) COWP 2 weeks later in late July. The primary gastrointestinal nematode was H. contortus (70%). Between Days 7 and 35, FEC were greater in 0 and 0.5 g COWP groups compared with ewes administered 2 g COWP (COWP x day, P<0.004). PCV decreased in all groups of ewes between Days 0 and 21 (day, P<0.001). Aspartate aminotransferase (AST) activity, a measure of liver copper levels, and body weight was similar among groups of ewes. FEC decreased within 7 days in COWP-treated compared with untreated lambs and remained low throughout experiment (COWP x day, P<0.05). PCV increased in COWP-treated lambs between Days 7 and 35 and decreased in untreated lambs between Days 0 and 21 (COWP x day, P<0.009). AST activity was similar among groups of lambs. Administration of 2 g COWP to ewes prevented a rise in FEC, but a dose of 0.5 g was ineffective as an anthelmintic. Administration of all doses of COWP to lambs decreased FEC and increased PCV compared to untreated lambs. There were no signs of copper toxicity in ewes or lambs. Alternative suppression of H. contortus infections may be necessary in ewes, but COWP was effective in H. contortus management for lambs. 相似文献
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Gauly M Schackert M Hoffmann B Erhardt G 《DTW. Deutsche tier?rztliche Wochenschrift》2006,113(5):178-181
36 intact male and 69 female lambs of two breeds (n = 63 Merinoland; n = 42 Rh?n) aged 12 weeks were orally infected with 5000 infective-stage larvae, L3, of the nematode Haemonchus contortus. After 4 and 8 weeks faecal egg counts (FEC), haematocrit values and plasma testosterone levels were determined. All lambs were slaughtered at 20 weeks of age. The gastrointestinal tracts were examined for the presence of adult stages of H. contortus. Male lambs showed significantly higher log FEC (p < 0.001), higher mean establishment rates (p < 0.05), higher worm burdens (p < 0.01) and lower haematocrit values (p < 0.001) when compared with female lambs. Correlations between economically important traits (body weight, daily weight gain) and parasitological parameters were significantly higher in male animals. Testosterone level was 4 weeks after infection significantly positive correlated with worm burden. The results suggest that female lambs are more resistant against an experimental H. contortus infection when compared with male lambs. Testosterone seems to play an important role in resistance. This approach can be of importance if parasite resistance is incorporated into breeding programs and the estimated breeding values for rams are only based on male offspring information. Therefore male breeding values are probably not representative for the whole population. 相似文献