Voluntary feed intake and diet selection of Merino sheep divergently selected for genetic difference in resistance to Haemonchus contortus

2011 ◽  
Vol 177 (3-4) ◽  
pp. 316-323 ◽  
Author(s):  
E.K. Doyle ◽  
L.P. Kahn ◽  
S.J. McClure ◽  
J.M. Lea
Keyword(s):  
Feed Intake ◽  
Haemonchus Contortus ◽  
Genetic Difference ◽  
Diet Selection ◽  
Merino Sheep ◽  
Voluntary Feed Intake ◽  
Selection Of

scholarly journals Lack of response to garlic fed at different dose rates for the control of Haemonchus contortus in Merino wether lambs

2009 ◽  
Vol 49 (12) ◽  
pp. 1093 ◽  
Author(s):  
V. J. Strickland ◽  
J. S. Fisher ◽  
W. T. Potts ◽  
G. W. Hepworth
Keyword(s):  
Feed Intake ◽  
Haemonchus Contortus ◽  
Body Condition Score ◽  
Control Group ◽  
Feed Conversion ◽  
Worm Count ◽  
Treatment Groups ◽  
Dose Rates ◽  
Voluntary Feed Intake ◽  
Over Time

With the increased incidence of parasite resistance to chemical anthelmintics worldwide novel approaches to manage parasite infection, such as medicinal plants and their extracts, are being investigated by the scientific community. The current study tested the effect of three rates of garlic (0.9, 1.8 and 3.6%) in a pelleted ration on Haemonchus contortus in sheep. Thirty-nine Merino wether lambs aged 6 months were divided into five treatment groups, including three garlic dose rates and two control groups that received no garlic. All animals were infected with 4000 L3 H. contortus larvae 3 weeks after allocation to treatments. A positive control group was drenched with abamectin 28 days after infection. The synthetic drench was effective in controlling the parasites, but there was no reduction in either worm egg counts (WEC) or total worm count due to the garlic. The 3.6% garlic treatment had significantly lower (P < 0.05) liveweight, feed intake, body condition score and feed conversion ratio than any of the other treatment groups, suggesting that this level of garlic had a low level of anti-nutritional properties. There was an interaction between faecal WEC and voluntary feed intake over time, with the animals with higher voluntary feed intake having lower WEC over time.

Pumpkin kernel and garlic as alternative treatments for the control of Haemonchus contortus in sheep

2009 ◽  
Vol 49 (2) ◽  
pp. 139 ◽  
Author(s):  
V. J. Strickland ◽  
G. L. Krebs ◽  
W. Potts
Keyword(s):  
Body Condition ◽  
Feed Intake ◽  
Haemonchus Contortus ◽  
Initial Level ◽  
Body Condition Score ◽  
Clinical Signs ◽  
Residual Effect ◽  
Voluntary Feed Intake ◽  
Significant Difference ◽  
Condition Score

Two alternative remedies for controlling Haemonchus contortus in sheep (pumpkin kernel and garlic) were investigated. The experiment involved 18 4-month-old Merino ram lambs with six lambs per treatment group. The lambs were initially drenched to render them worm free, and then infected with 4000 L3 H. contortus larvae, 2 weeks later. Four weeks after infection, faecal egg counts were performed and lambs were allocated into treatment groups and fed their respective diets (control, pumpkin kernel or garlic) for 2 weeks. The lambs were combined into a single group grazing pasture for the last week of the experiment. Faecal worm egg counts (WEC) were carried out weekly for 3 weeks following allocation to treatment diets. Clinical signs of infection observed included liveweight, body condition score and voluntary feed intake. The pumpkin kernel treatment resulted in a 65.5% decrease in the initial level of WEC, but this increased back to the initial level as soon as animals came off treatment. The garlic resulted in a 64.4% decrease in WEC from the initial level and this increased slightly (to 25.5% of the initial level and 43.5% lower than the control) when the animals came off treatment, suggesting that there was a residual effect of the garlic and/or that the garlic had an effect beyond decreasing the fecundity of the parasites. There was no significant difference (P > 0.05) between treatments in liveweight, body condition score or voluntary feed intake. Throughout the experiment voluntary feed intake and liveweight increased while body condition scores remained stable. We concluded that pumpkin kernel and garlic show potential for parasite control by affecting the fecundity of the parasites. Our results also indicate that with good nutrition lambs can cope with high parasite burdens and still be productive during the early stages of infection.

Grazing behaviour - diet selection and pasture intake.

2021 ◽  
pp. 169-183
Author(s):  
Gordon McL. Dryden
Keyword(s):  
Feed Intake ◽  
Foraging Behaviour ◽  
Diet Selection ◽  
Nutritional Environment ◽  
Selection Of ◽  
Grazing Behaviour

Abstract In this chapter the nutritional environment, foraging behaviour, feed intake, and diet selection of grazing animals are discussed.

The effect of subclinical intestinal nematode infection on the diet seletion of growing sheep

1994 ◽  
Vol 72 (5) ◽  
pp. 665-677 ◽  
Author(s):  
I. Kyriazakis ◽  
J.D. Oldham ◽  
R.L. Coop ◽  
F. Jackson
Keyword(s):  
Feed Intake ◽  
Live Weight ◽  
Diet Selection ◽  
Metabolizable Energy ◽  
Protein Requirements ◽  
Intestinal Nematode ◽  
Ewe Lambs ◽  
Daily Rate ◽  
Reduced Rate ◽  
Selection Of

To test the hypothesis that subclinical gastrointestinal parasitism, associated with an impairment in N digestion and metabolism and a reduction in the voluntary feed intake (VFI), could affect the diet selection of sheep given a choice between two feeds that differed in their crude protein (CP) content, twenty-four Texel ×Scottish Blackface ewe lambs growing from 28 to 48 kg live weight (LWT) were given a daily dose of 2500 larvae of the intestinal nematode Trichostrongylus colubriformis; twenty-four similar lambs were used as uninfected controls. Six infected and six control lambs were given a free choice between two pelleted feeds (10·4 MJ metabolizable energy/kg), wilh different CP contents (90 (L) and 214 (H) g CP/kg fresh feed respectively). In addition, eighteen parasitized and eighteen control sheep were given access ad lib. to either feed L, or feed H, or their mixture M (164 g CP/kg; twelve per feed), in order to quantify the effects of the feeds when offered alone, and to test for any interactions between feed CP content and parasitism on the performance of the lambs. Intestinal parasitism reduced significantly (P < 0·001) both the rates of LWT gain (by 30%) and VFI (by 10%). The adult and developing parasitic forms took 4 weeks to establish and develop to a significant adult worm population (as judged by the faecal egg counts and blood variables) and until then there was no effect of parasitism on the performance of the lambs. The diet selection of the lambs given a choice between two feeds was similar between the two groups in the first 4 weeks of the experiment, but differed significantly (P < 0·05) in the second part of the experiment (4th week to the end). Thus, while parasitized lambs had a reduced rate of feed intake, by changing their diet selection they achieved a daily rate of CP intake similar to the control ones. However, since the parasitized lambs had a reduced rate of LWT gain, they also consumed a higher total amount of CP to reach the same LWT. It is concluded that sheep infected daily with a small number of larvae of T. colubriformis and given a choice between two feeds that differ in their protein contents are able to modify their diet selection in order to meet the increased protein requirements resulting from such an infection.

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