Discipline: Biological Sciences
Serena R. Joseph - University of the Virgin Islands
Co-Author(s): Whitney George, Lucas LaPlace, and Robert Godfrey, University of the Virgin Islands, Agricultural Experiment Station, St. Croix USVI
St. Croix White (STX) hair sheep have a high tolerance to gastrointestinal nematodes (GIN) compared to other breeds of sheep. Haemonchus contortus is a parasitic nematode that causes anemia. The objective of the study is to evaluate the impact of weaning St. Croix White and Dorper X St. Croix White (DRPX) lambs at 63 (control) 90 or 120 days of age on GIN burden of ewes and lambs pre- and post-weaning. Ewes (n=46) and lambs (n=63) were used. Lambs were assigned to treatment groups based on breed and litter size. Treatments consisted of weaning lambs at 63, 90, or 120 days of age. Prior to weaning, ewes and lambs grazed (Panicum maximum) pastures in a rotational grazing system. After weaning, lambs were weighed weekly and fed a concentrate diet while grazing guinea grass pasture. Ewes were weighed weekly throughout the data collection. Jugular blood samples used to determine packed cell volume (PCV), FAMACHA score (1 = no anemia to 5 = high level of anemia), fecal samples and weight were collected from each ewe and lamb at 63, 90 and 120 d of age of lamb. Fecal egg counts (FEC) were determined using the modified McMasters technique. Prior to analysis FEC was transformed using log10 (FEC + 1). Data was analyzed using general linear models procedures using breed and treatment as main effects. The STX lambs had a lower FAMACHA score than DRPX lambs (1.8 ± 0.1 vs. 2.4 ± 0.1, respectively). The PCV was not different (P > 0.10) between STX and DRPX lambs (30.9 ± 0.4 vs. 32.7 ± 0.4 %, respectively) or among lambs weaned at 63, 90 or 120 d (31.7 ± 0.5 vs. 30.9 ± 0.5 vs. 32.7 ± 0.5 %, respectively). There was no difference in FEC between STX and DRPX lambs (1,518 ± 240 vs. 1468 ± 214 egg/gm, respectively) or among lambs weaned at 63, 90 or 120 d of age (1,369 ± 269 vs. 1,174 ± 284 vs. 1,936 ± 283 egg/gm, respectively). There was no difference (P > 0.10) in FAMACHA score between STX and DRPX ewes (2.4 ± 0.1 vs. 2.7 ± 0.1, respectively). The PCV was not different (P > 0.10) between STX and DRPX ewes (27.3 ± 0.5 vs. 27.9 ± 0.4 % respectively) or among ewes weaned at 63, 90 or 120 d of age of lambs (27.4 ± 0.6 vs. 28.8 ± 0.6 vs. 26.5 ± 0.5 %, respectively). The STX ewes had lower (P < 0.005) FEC than DRPX ewes (170 ± 231 vs. 998 ± 175 egg/gm, respectively). There was no difference (P > 0.10) in FEC among ewes that had lambs weaned at 63, 90 or 120 d of age (350 ± 251 vs. 382 ± 258 vs. 1,020 ± 244 egg/gm, respectively). In conclusion, weaning age does not affect the parasite burden of either breed of lambs or ewes, further supporting the use of later weaning ages of hair lambs in an accelerated lambing system. Future studies include evaluating quantitative trait loci that is linked to parasite resistance.
Funder Acknowledgement(s): This research was supported by NIH MBRS-RISE Research Program Grant Reward No. 5R25GM061325.
Faculty Advisor: Robert Godfrey, firstname.lastname@example.org
Role: During the study I was able to proceeded with FAMACHA Score of lambs and ewes. In addition to weaning subjects at 63, 90 and 120 days of age. In conclusion, centrifugation, jugular blood samples, analyzing pack cell volume and completing fecal floatation test were also completed. I also completing reviews on similar projects regarding Haemonchus contortus burden in sheep.