@article {3672, title = {Anthelmintic resistance: a perspective on our current understanding and ability to control this problem}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {105-108}, address = {Lincoln}, abstract = {Regimens to prevent the development of anthelmintic resistance (AR) have been promoted for many years. All reflect some appreciation of the selection pressure that different anthelmintic treatment policies apply to nematodes but AR is clearly more complicated than this for reasons we still do not yet understand sufficiently well. Whilst managing a refugia population on a farm is important to limit the development of AR there are many aspects that are not understood. Why is AR more common in some species than others, especially for some such as Dictyocaulus where there is clearly a short-lived refugia population and heavy selection pressure yet no recorded AR. The cost of AR to farmers has slowly escalated over the years and using a New Zealand example it can be estimated for a typical sheep farm that the cost of using a single active of an older anthelmintic such as levamisole compared to a newer anthelmintic such as monepantel is about NZ$3.27 per lamb raised. Diagnosis of AR continues to largely rely on the use of faecal egg count reduction tests. These are a very crude tool but generally acceptable for sheep. However, for cattle and farmed deer it is difficult to get egg counts high enough to conduct a meaningful test. Clearly more effort is needed to understand the mechanisms associated with AR and to develop better diagnostic tests so that farmers with their advisors are better able to achieve sustainable helminth control.}, issn = {1176-5283}, author = {Pomroy WE} } @article {3672, title = {Lamb castration and tailing practices in New Zealand: results of a questionnaire}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {96-99}, address = {Lincoln}, abstract = {There is a large body of literature that has examined the impacts of castration and tailing on lamb behaviour, stress response, pain and productivity (Fisher et al. 2010; Kent et al. 1993; Mellor et al. 2002; Mellor \& Stafford 2000). Recently, Kerslake et al. (2015) investigated lamb tail docking, residual tail length and the reasons behind farmers{\textquoteright} choice to dock. There is little information available, however, regarding castration methods and reasons for the choice of leaving lambs entire, castrated or short-scrotumed. A printed questionnaire was distributed to ~12,000 farmers on the Beef + Lamb New Zealand database. The questionnaire contained 30 questions on aspects of management of flystrike, louse control, tailing and castration. Information was sought regarding percentage of lambs tail docked, method used to remove tails, reason for the tailing decision, proportions of male lambs left entire or castrated or short scrotumed, the method used to castrate or short-scrotum, and the reason for choice of male lamb type. A total of 1253 (10\%) of questionnaires were returned. Of the farmers that responded, the most commonly used tailing method was a hot iron (61\%), followed by rubber rings (31.4\%). Lamb growth was the primary reason that farmers gave for leaving lambs entire, and to a lesser degree short-scrotum. The reason behind the decision to castrate was most commonly related to lamb behaviour, however, a number of reasons had similar frequencies (lambs stay cleaner, infertility and meat quality).}, issn = {1176-5283}, author = {Corner-Thomas RA and Ferguson MB and Kenyon PR and Stafford KJ and Pomroy WE} } @article {3672, title = {Pasture use and management in commercial equine production systems}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {40-44}, address = {Lincoln}, abstract = {Despite a perceived reliance of horses on pasture there are limited data on efficiency of pasture utilisation in equine production systems. The unique equine behaviour characteristics of highly selective browsing, combined with faecal avoidance, provide distinct grazing management challenges compared to those of ruminants. Data reported here show that faecal avoidance results in the establishment of lawns and roughs (overgrazed and poorly grazed areas, respectively) with it estimated that only 70\% of the total pasture DM/ha on offer is utilised by horses. During spring, lawns contained more grass (74\% vs 53\%) and clover (5\% vs 3\%) and less weeds (2\% vs. 11\%) and dead matter (19\% vs. 33\%) than did roughs. Weanlings will start to graze roughs once the lawns are <1500 kg DM/ha. Roughs, however, will not be grazed within 1 m of a faecal pile. This translates to a lower pasture utilisation rate in weanlings and the biased grazing pattern means estimates of total pasture DM over-estimate the true available pasture DM. The relative proportion of pasture in lawns and roughs changes during grazing and prevents the application of a simple correction factor to estimate available DM. Broodmares had greater rates of pasture utilisation and less bias for consumption of pasture in areas of roughs than did weanlings.}, issn = {1176-5283}, author = {Rogers CW and Gee EK and Back PJ and van Zon S and Hirst RL and Pomroy WE} } @conference {75879, title = {BRIEF COMMUNICATION: The effect of dam age and lamb birth rank on the growth rate, faecal egg count and onset of puberty of single and twin female offspring to 12 month of age}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {83-85}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Breeding ewe lambs at eight to nine months of age has gained popularity on New Zealand sheep farms in recent years. This is predominantly because of the many production advantages it offers: greater net profits, increased number and weight of lambs produced per ewe productive lifetime, better use of spring herbage, early recognition of fertility potential, increased rates of genetic gain and... Continued}, issn = {1176-5283}, author = {Loureiro MFP and Paten AM and Asmad K and Pain SJ and Kenyon PR and Pomroy WE and Scott I and Blair HT} } @conference {75873, title = {BRIEF COMMUNICATION: The effects of dam nutrition during pregnancy on the postnatal growth and puberty attainment of ewe progeny}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {56-58}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {In New Zealand{\textquoteright}s pastoral sheep-production systems, feed can become limiting during winter, when breeding ewes are pregnant. Ewes are often restrictively fed during early-gestation (Kenyon \& Webby, 2007) to enable greater levels of nutrition in late-gestation. Many studies have demonstrated that dam nutrition during various stages of pregnancy can program the...}, issn = {1176-5283}, author = {Paten AM and Asmad K and Loureiro MFP and Kenyon PR and Pain SJ and Peterson SW and Pomroy WE and Scott I and Blair HT} } @conference {75874, title = {BRIEF COMMUNICATION: The effects of dam nutrition during pregnancy on the growth of male offspring}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {59-61}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {During pregnancy, nutritional status of the ewe is crucial because of its potential effect on fetal development, subsequent lamb survival and reproduction post-birth (Rhind et al., 2001). Manipulation of the progress of fetal development can affect the structure and physiology of adult offspring through the process of fetal programming (Barker et al., 1993). Epidemiological data... Continued }, issn = {1176-5283}, author = {Asmad K and Paten AM and Loureiro MFP and Kenyon PR and Pain SJ and Parkinson TJ and Pomroy WE and Scott I and Blair HT} } @conference {41609, title = {Lessons from the national anthelmintic resistance surveys}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {23-26}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Dexcel{\textquoteright}s Whole Farm Model (WFM) is a computer model of a dairy farm that simulates individual cows and paddocks, with pasture growth driven by observed climate data and with management policies guiding decisions on a daily basis. The aim of the study was to design a farm system to produce 1750 kg milksolids (MS)/ha/yr from feed grown on-farm. An average predicted pasture growth curve was derived by initialising the WFM for a typical all-pasture Waikato farm (3 cows/ha) with "best practice" management policies and running the simulation for 29 years of Ruakura climate data. The model was then used with this average growth curve to design the high producing system. Pasture growth alone (17.3 t DM/ha) did not fulfil the feed requirement for the 1750 kg MS/ha scenario, with an overall feed deficit of 3.1 t DM pasture/ha. Improvements in ryegrass cultivars and N-fertilisers could be expected to increase pasture production by around 10\%, reducing the overall feed deficit to 1.6 t DM pasture/ha. These improvements together with irrigation at 2 mm/day over the three summer months (Dec - Feb) reduced the feed deficit to zero. Irrigation could be replaced by cropping between 11\%and 20\% of the farm in a rotation of annual ryegrass yielding 7 t DM/ha and maize yielding 22 to 28 t DM/ha respectively.}, issn = {1176-5283}, author = {Pomroy WE} } @conference {41859, title = {A profile of anthelmintic resistance and parasite control practices in New Zealand - results from a 2005 survey}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {14-19}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Anthelmintic (drench) resistance in New Zealand{\textquoteright}s ruminant livestock is arguably the biggest single threat to sustainable future pastoral production. Clinical and sub-clinical parasitism impacts not only on animal health, but on animal welfare, and hence the image of pastoral production systems, total production and production efficiency and has a marked impact on the economic bottom line for both farmers and the country as a whole. In 2001 it was estimated for the relatively small NZ deer industry alone (worth $311 million in export earnings) that parasitism cost $12.8 million per annum in production losses due to parasitism and parasite control (Mackintosh and Wilson, 2002).}, issn = {1176-5283}, author = {Rhodes AP and Leathwick DM and Pomroy WE and West DM and Jackson R and Lawrence K and Moffat J and Waghorn TS} } @conference {40551, title = {The relationship between internal parasite burden, faecal egg count, and mucosal mast cells in fleeceweight-selected and control sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {9-14}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Research has shown that sheep from a Massey University flock selected for increased fleece weight (FW) for thirty-six years have higher faecal egg counts (FEC) than unselected controls (C). The purpose of this trial was to determine whether differences in FEC between FW and C sheep accurately reflected differences in adult worm burdens. In addition levels of mucosal mast cells, and their relationship with worm burden in each line were examined. Thirteen one year-old rams from each flock were housed indoors and artificially infected with larvae of three species of nematode parasite: Haemonchus contortus, Ostertagia circumcincta, and Trichostrongylus colubriformis. FECs were monitored and adult worm burdens, and levels of mucosal mast cells, determined following slaughter 28 days after infection. FECs were higher in FW than C sheep (4204 vs 300 epg, p<0.0001), as were numbers of adult Haemonchus (1151 vs 249, p<0.01) and Ostertagi (2268 vs 600, p<0.05). Numbers of Trichostrongylus (5838 vs 5266) and total worm burden (9257 vs 6115) were not significantly different between lines. A {\textquoteright}Total Pathogenic Index{\textquoteright}, calculated from the number of parasites of each species present in the total burden, was higher in FW than C sheep (3.8 vs 1.5, p<0.005). The regression coefficient relating FEC to worm burden was larger in FW than C sheep (0.35 vs 0.05 eggs per g faeces/worm, p<0.01). Levels of mucosal mast cells did not differ significantly between lines, but were inversely related to number of worms in FW sheep. There was no such relationship in C sheep. It is concluded that while the large differences in FEC between lines overestimates the difference in total worm burden, FW sheep do carry significantly more worms of the abomasal species H. contortus and O. circumcincta than C sheep. FW sheep are able to maintain superior wool production in spite of this potentially more pathogenic worm burden. The mucosal mast cell response to parasitic infection also appears to have been changed by selection. }, issn = {1176-5283}, author = {Williamson JF and Blair HT and Garrick DJ and Pomroy WE and Douch PGC} } @conference {40376, title = {A comparison of internal parasitism in fleeceweight-selected and control Romney sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {57-60}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Rising three year old Angus steers were fed on either ryegrass/subterranean clover pasture or a high grain ration (70\% maize grain/ 30\% pasture silage) for an adjustment period of 2 weeks and an experimental period of 12 weeks. Then cattle were slaughtered initially and 10 cattle from each treatment group were slaughtered after 6, 10 and 14 weeks. Cattle offered the high grain ration had feed intakes of up to 2.7\% of bodyweight and over the 12 weeks experimental period average liveweight gains of 1.4 and 2.0 kg/d were achieved in the pasture and grain fed groups, respectively. Carcass weight increased from 316 kg to 363 kg in the pasture group and 406 kg in the grain fed group at final slaughter. Intramuscular (chemical) fat at the 12th rib increased from 13\% to 23\% and was not affected by diet. Levels of intramuscular fat were up to 38\% and were similar to those reported for Japanese Wagyu beef. Lean meat colour was significantly brighter (P<0.001) as a result of grain feeding and the incidence of yellow fat was reduced. }, issn = {1176-5283}, author = {Howse SW and Blair HT and Garrick DJ and Pomroy WE} }