Are Scottish Blackface ewes more resistant to nematode parasite infection than Greyface ewes?

2009 ◽  
Vol 2009 ◽  
pp. 28-28
Author(s):  
A Kidane ◽  
J G M Houdijk ◽  
B J Tolkamp ◽  
S Athanasiadou ◽  
I Kyriazakis
Keyword(s):  
Genetic Resistance ◽  
Gastrointestinal Nematode ◽  
Parasite Infection ◽  
Nematode Parasite ◽  
Nutrient Demand ◽  
Nematode Parasites ◽  
Breed Differences ◽  
Lower Extent ◽  
Ad Libitum ◽  
Per Se

The extent of periparturient relaxation of immunity (PPRI) to gastrointestinal nematode parasites is sensitive to metabolisable protein (MP) scarcity but also varies between breeds of sheep (Houdijk, 2008). For example, under ad libitum feeding, Scottish Blackface ewes had a lower extent of PPRI than Greyface ewes (Zaralis et al., 2008). Such between-breed variation in PPRI may not necessarily be associated with genetic resistance per se but could arise from a higher nutrient demand of the more productive Greyface ewes (Houdijk, 2008). This experiment was designed to test the hypothesis that if the extent of PPRI has only a nutritional basis, then the sensitivity of PPRI to MP scarcity will not differ between the breeds when MP feeding is adjusted for between-breed differences in MP demand.

Genetic resistance to gastrointestinal nematode parasites in Polish long-wool sheep

1998 ◽  
Vol 28 (11) ◽  
pp. 1797-1804 ◽  
Author(s):  
J. Bouix ◽  
J. Krupinski ◽  
R. Rzepecki ◽  
B. Nowosad ◽  
I. Skrzyzala ◽  
...  
Keyword(s):  
Genetic Resistance ◽  
Gastrointestinal Nematode ◽  
Nematode Parasites

Genetic resistance to endoparasites in sheep and goats. A review of genetic resistance to gastrointestinal nematode parasites in sheep and goats in the tropics and evidence for resistance in some sheep and goat breeds in sub-humid coastal Kenya

1998 ◽  
Vol 24 ◽  
pp. 13-30 ◽  
Author(s):  
R.L. Baker
Keyword(s):  
Genetic Variation ◽  
Genetic Resistance ◽  
Gastrointestinal Nematode ◽  
East African ◽  
Sheep And Goats ◽  
Nematode Parasites ◽  
Coastal Kenya ◽  
Dorper Sheep ◽  
The Tropics ◽  
Published Research

SummaryThe evidence for both between- and within- breed genetic variation for resistance to gastrointestinal (GI) nematode parasites is reviewed. It is concluded that much of the published research on breed characterisation for resistance suffers from poor experimental design. Prior to the initiation of a 6-year study that has just been completed in coastal Kenya there were no estimates of within-breed genetic variation (i.e. heritabilities) of resistance in sheep or goats in the tropics. This study has confirmed that Red Maasai sheep and Small East African (SEA) goats are more resistant to GI parasites (predominantly Haemonchus contortus) than Dorper sheep and Galla goats. Heritability estimates for logarithm transformed faecal egg counts (an indicator of resistance) in 8-month-old lambs was 0.18±0.08 for all lambs, but higher in the susceptible Dorper-sired lambs (0.35±0.16) than in the resistant Red Maasai-sired lambs (0.06±0.07). This difference in heritability suggests that many centuries of natural selection have fixed most of the genes for resistance in the Red Maasai sheep. The resistant Red Maasai sheep and SEA goats were two to three times more productive than the susceptible Dorper sheep and Galla goats in the sub-humid coastal Kenya environment.

scholarly journals The effects of changes in nutritional demand on gastrointestinal parasitism in lactating rats

2007 ◽  
Vol 97 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Heidi Normanton ◽  
Jos G. M. Houdijk ◽  
Neil S. Jessop ◽  
Dave P. Knox ◽  
Ilias Kyriazakis
Keyword(s):  
Crude Protein ◽  
Inflammatory Cells ◽  
Host Immunity ◽  
Nippostrongylus Brasiliensis ◽  
Protein Food ◽  
Treatment Groups ◽  
Nutrient Demand ◽  
Low Protein ◽  
Ad Libitum ◽  
Gastrointestinal Parasitism

Lactating rats experience a breakdown of immunity to parasites, i.e. they carry larger worm burdens after re-infection compared to their non-lactating counterparts. Feeding high-protein foods to lactating rats results in reduced worm burdens. This could be attributed to changes in gastrointestinal environment or to overcoming effects of nutrient scarcity on host immunity. The latter hypothesis was addressed through a manipulation of nutrient demand by manipulating litter size. Twenty-three rats were immunized prior to mating and re-infected on day 2 of lactation with 1600 infective Nippostrongylus brasiliensis larvae. From parturition onwards, rats received ad libitum a low-protein food (100 g crude protein/kg). Litter sizes were standardised to nine (LS9), six (LS6) or three (LS3) pups, by day 2 of lactation. After a further 10 d, LS9 and LS6 rats carried more worms than LS3 rats. However, feeding treatments did not affect concentrations of mucosal inflammatory cells. Achieved feed intake did not differ consistently between the treatment groups. However, LS9 and LS6 rats lost weight, whilst LS3 rats gained weight during lactation. The results support the view that resistance to N. brasiliensis is sensitive to changes in nutrient demand, and the improved resistance to N. brasiliensis is likely due to effects of overcoming nutrient scarcity on host immunity.

The epizootiology of gastrointestinal nematode parasites in Greek dairy breeds of sheep and goats

2003 ◽  
Vol 47 (3) ◽  
pp. 193-202 ◽  
Author(s):  
E Papadopoulos ◽  
G Arsenos ◽  
S Sotiraki ◽  
C Deligiannis ◽  
T Lainas ◽  
...  
Keyword(s):  
Gastrointestinal Nematode ◽  
Sheep And Goats ◽  
Nematode Parasites

The effect of level of environment on sex differences in pre-weaning growth rate in beef cattle

1977 ◽  
Vol 25 (1) ◽  
pp. 47-51 ◽  
Author(s):  
I. R. Hopkins
Keyword(s):  
Growth Rate ◽  
Sex Differences ◽  
Beef Cattle ◽  
Growth Rates ◽  
Additive Models ◽  
Regression Equations ◽  
Male And Female ◽  
Breed Differences ◽  
Per Se ◽  
Simple Regression

SUMMARYUsing pre-weaning records of 3822 calves from 11 Victorian herds, mean male and female growth rates and corresponding sex differences were calculated for each dam age and herd-year class. From these means simple regression equations relating sex differences and growth rates were calculated. There was a close similarity between equations based on dam age means and those based on herd-year means while correlations between sex differences and male growth rates were high.These results showed that sex differences and female growth rates could be predicted reliably from the level of environment as measured by male growth rate. Sex differences predicted by these regression relationships differed markedly from those predicted by the simple multiplicative and simple additive models generally used in adjusting for sex differences in selection.The results also suggested that other differences such as breed differences may be predictable in the same way and that such differences are determined primarily by the level of environment per se rather than differences in the nature of the components contributing to that level.

Assessment of genetic variability of resistance to gastrointestinal nematode parasites in Creole goats in the humid tropics.

2001 ◽  
Vol 79 (7) ◽  
pp. 1706 ◽  
Author(s):  
N Mandonnet ◽  
G Aumont ◽  
J Fleury ◽  
R Arquet ◽  
H Varo ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Gastrointestinal Nematode ◽  
Humid Tropics ◽  
Nematode Parasites
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