@conference {75871, title = {BRIEF COMMUNICATION: The influence of a herb and legume sward on maternal behaviour and lamb colostrum intake and thermoregulation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {50-52}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Nutrition of the ewe in late pregnancy is known to affect colostrum production, lamb live weight, survival to weaning (Kenyon \& Webby, 2007; Kerslake et al., 2009), and maternal behaviour (O{\textquoteright}Connor et al., 1985). Kenyon et al. (2010) reported that offering a mixed herb sward containing... Continued}, issn = {1176-5283}, author = {Hutton PG and Kenyon PR and Bedi MK and Kemp PD and Stafford KJ and West DM and Morris ST} } @conference {75878, title = {Is there any advantage of early weaning of twin lambs born to yearlings?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {79-82}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {The objective of the current study was to investigate the effect of weaning twin lambs born to yearlings at 9, 11 or 13 weeks of age on the live weight of the yearling and her lambs. The yearlings and the lambs were allocated to one of three weaning treatment groups (9-week versus 11-week versus 13-week) on Day 1. Each treatment group was balanced for yearling and lamb live weight. At Week 13, all lambs were removed from the remainder of the experiment but the yearlings were monitored for a further six weeks. The yearlings and lambs were offered ad-libitum levels of herbage throughout the experimental period and the pre- and post-grazing mass was monitored weekly. The yearlings and lambs were weighed on Days 1, 7, 14, 21 and 28 while yearlings were weighed again on Days 35, 42 and 70. Pre- and post-grazing mass was monitored weekly. Yearling live weight did not differ (P >0.05) between treatment groups on Days 1, 35 or 70. Lamb live weight did not differ (P >0.05) on Days 1, 14 or 28. These results indicate that there is no advantage of early weaning of twin lambs born to yearlings on the live weight of the yearling or her lambs.}, issn = {1176-5283}, author = {Mulvaney FJ and Morris ST and Kenyon PR and Morel PCH and West DM} } @conference {69479, title = {Effect of nutrition around the time of breeding and during pregnancy on yearling liveweight change, pregnancy loss and liveweight and survival of of their offspring}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {91-95}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {This experiment investigated the effects of differing nutritional levels on yearling pregnancy loss, and the live weight and survival of their offspring to weaning. Yearlings were offered either Medium or Ad-libitum levels of herbage from four days prior to breeding (P-4) until P145. Nutrition during pregnancy had no effect on pregnancy loss or lamb live weight from Day 0 of lactation (L0) until L55. Lambing percent was higher (P <0.05) in the Ad-libitum treatment compared to the Medium treatment. Single born lambs were heavier (P <0.05) than twin born lambs at L0 and at L55. Ad-libitum treatment yearlings were heavier (P <0.05) than Medium treatment yearlings at L55. Modelling of the live weight trends indicated that from P-4 until P145 the pregnant yearlings in the Medium and Ad-libitum treatment groups consumed 8.1 and 14.4 kg DM/kg of lamb live weight at L55. This indicates that the greater yearling live weight gain in the Ad-libitum group utilised more herbage during the yearling{\textquoteright}s first winter without any increase in the performance of their offspring. The extra 9 kg gained by the yearlings fed Ad-libitum may have positive effects on future performance as they will gain a suitable live weight for breeding as a two year old earlier.}, issn = {1176-5283}, author = {Mulvaney FJ and Morris ST and Kenyon PR and West DM and Morel PCH} } @conference {69524, title = {The efficacy of a herbal drench treatment on internal parasites in lambs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {283-284}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Internal parasites reduce live weight gains and are a cause of diarrhoea in growing lambs (Macchi et al., 2001). A challenge to organic sheep production is the control of internal parasites without intervention using synthetic chemicals. Whilst in conventional sheep production systems anthelmintic resistance to synthetic chemicals is increasing (Pomroy, 2006). The development of an effective herbal worm drench that can be commercialised will allow the organic sheep sector to develop and may offer an alternative for conventional systems.}, issn = {1176-5283}, author = {Hutton P and Scott I and Schreurs NM and West DM} } @conference {60945, title = {The effect of weaning at 10 or 14 weeks of age on liveweight changes in the hogget and her lambs : Brief Communication}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {68-70}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Kenyon et al. (2004) revealed via a survey, that a major reason why New Zealand farmers do not breed ewe hoggets (7-9 months old) is perceived detrimental effects on two-tooth breeding live weight, resulting in reduced two-tooth reproductive performance. Kenyon et al. (2008) confirmed this by showing hoggets that lambed had reduced two-tooth live weight and condition score at breeding. A potential means of minimising any potential negative effects on... Continued}, issn = {1176-5283}, author = {Mulvaney FJ and Morris ST and Kenyon PR and West DM and Morel PCH} } @conference {41699, title = {To wether - short scrotum or leave lambs as entire rams ? Revisiting an old question using new genetics}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {67}, year = {2007}, month = {Jan}, pages = {44-47}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Wanaka}, abstract = {A comparison of wethers (WTH), short scrotum (SSC) and rams (RAM) was made on 552 7/16 Romney, 3/16 Poll Dorset, 3/16 Texel and 3/16 East Friesianlambs. Lambs were drafted for slaughter using commercial criteria on weight and condition score at weaning (D81), D120, D154 and D192. Due to faster growth rates, by the end of the 2nd kill (D120) approximately 31\% of RAM and SSC lambs were slaughtered compared with 16\% of WTH lambs (P<0.01), although the difference was no longer significant by the end of the 4 th kill. The carcass weight of WTH (17.6kg) was significantly heavier (P<0.01)than the RAM (17.2kg) but not significantly different to the SSC (17.5kg), despite similar kill liveweights, due to the increased dressing out percentages of the WTH lambs (43.6\%, 43.1\% and 42.5\% respectively; P<0.05). Based on GR, 8.7\% of WTH carcasses graded overfat, compared with only 0.6\% of RAM and SSC carcasses (P<0.001). Over the kill period the price schedule ($/kg carcass weight) dropped, so for the WTH given their longer time to slaughter and poorer grading due to over fat carcasses the price for WTH carcasses ($49.16) was lower (P<0.01) than RAM or SSC carcasses ($50.37 and $50.70). When the added cost of feeding and drenching was taken into consideration, the net value of the WTH was evenless. Composite wether lambs of still potentially present an opportunity cost, except incertain situations where the management benefits outweigh the direct financial cost. }, issn = {1176-5283}, author = {PL Johnson and Kenyon PR and Burnham DL and West DM} } @conference {41940, title = {The effect of maternal nutrition during gestation on the reproductive success of female progeny as 2-tooths}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {434-438}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {The inter-generational effect of birth rank and nutrition during pregnancy was assessed by examining the reproductive success of female progeny at their first mating at 2 years of age. Fifty-six ewes born as a twin or triplet and whose dam was maintained on 2 or 6 cm sward height from mid-pregnancy to parturition were synchronised and bred to Romney rams. Pregnancy diagnosis was conducted using ultrasound on day 71 from the start of mating (P71). All ewes were maintained as one mob under commercial farming conditions throughout pregnancy. Within 12 hours of birth lambs were ear tagged, weighed and body dimensions (CRL, girth, forelimb and hind limb lengths) were recorded. Lamb live weights were also recorded at day 48 after the mid-point of lambing (L48). Fifty-one ewes lambed of the 56 ewes that were bred. Twin-born ewes had significantly longer gestation lengths (by 1.3 days) than triplet-born ewes. Singleton lambs born to triplet-born ewes were significantly (P<0.05) lighter (4.6 kg) at birth than singleton lambs born to twin-born ewes (5.1 kg). Singleton lambs whose grand-dams were maintained on 2cm pastures during pregnancy and whose dam was born as a twin had significantly (P<0.05) longer hind limbs than their counterparts whose grand dam was maintained on 6 cm and whose dam was born a triplet but they did not differ in birth weight. Dam birth rank and the nutritional treatment of their grand-dam had no significant effect on twin-lamb live weight and body dimensions at birth. These results suggest that selecting triplet ewe lambs for breeding could have detrimental effects on flock productivity. In addition a previous study involving the same animals reported triplet born ewes displayed poorer maternal behaviour. To the authors knowledge this is the first finding of this kind and could have implications for ewe selection on New Zealand farms. }, issn = {1176-5283}, author = {Corner RA and Kenyon PR and Stafford KJ and West DM and Morris ST} } @conference {41689, title = {The effect of nutrition during pregnancy on the behaviour of adolescent ewes and their lamb(s) within 12 hrs of birth}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {439-443}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Hogget mating has become more common in recent times as a management strategy to produce additional lambs. The productivity of hogget mating is limited by low lamb birth weights and poor lamb survival. A study has shown that maternal nutrition during pregnancy in hoggets had no effect on the birth weight or survival of lambs. This study investigated the effect of nutrition during pregnancy on the post-parturient behaviour of hogget ewes and their lambs. On day 13 after the mid-point of breeding hogget ewes were stratified by breed and live weight and randomly allocated to one of three feeding regimes: Low (gained 10kg of live weight by parturition), Medium (20kg) and High (30kg). Within 12 hours of birth lambs were ear tagged and the maternal behaviour of hogget ewes was recorded using a maternal behaviour score (MBS) a five point measure of a ewe{\textquoteright}s response to the handling of her lambs. Behavioural observations of the hogget and her lamb(s) were made for 5 minutes after the completion of tagging the lamb. Singleton-bearing hogget ewes fed on the high plane of nutrition had significantly (P<0.05) greater maternal behaviour scores than singleton-bearing hoggets fed on low or medium planes. In the low fed group, significantly (P<0.05) fewer hoggets bleated in response to their lamb (60\%) compared with medium (73\%) and high (85\%) fed hoggets. Of the lambs that bleated, those born to hoggets in the medium fed group bleated significantly (P<0.05) more than lambs born to hoggets in the low or high fed groups. Feeding hogget ewes on a high level of nutrition had a positive impact on hogget and lamb behaviour within 12 hours of birth. A high level of nutrition during pregnancy may result in behaviours that increase survival of lambs born to hogget ewes. }, issn = {1176-5283}, author = {Corner RA and Kenyon PR and Stafford KJ and West DM and Morris ST} } @conference {41639, title = {Effect of Se-amended fertilisers on the Se status of grazing dairy cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {182-186}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Selenium (Se) is an important trace element for dairy cattle and deficiencies (0.03 mg Se/kg DM) are associated with lowered milk yields and impaired fertility in grazing cows. As many dairy farms have a comprehensive fertiliser programme the use of Se-amended fertilisers (prills) could be an effective approach to prevent Se deficiency. Three farmlets (6-7 ha) were established and grazed with 13 cows/farmlet balanced for age, calving date and production. The treatments were 1) untreated control, 2) Sel Se prill (Selecote Ultra), and 3) Rav Se prill (Ravensdown Selprill Double). The prills were mixed with 15\% potassic superphosphate and applied at 250 kg/ha, in early October, to provide 10 g Se/ha. This is Day 1 of the study. The cows were allocated to treatments 4 weeks later and changes in pasture Se, blood Se, serum Se, milk Se concentrations and blood glutathione peroxidase activity were monitored over the next 12 months. Untreated pasture Se concentrations ranged from 0.03 to 0.04 mg/kg DM, while pastures treated with prills had pasture Se concentrations > 0.5 mg/kg DM within 14 days after treatment, before decreasing to 0.06 mg/kg DM after 121 days, after which they ranged between 0.06 and 0.26 mg Se/kg DM for the Sel prill, and between 0.06 and 0.03 mg/kg DM for the Rav Se prill over the next 251 days. The mean ({\textpm} SE) blood Se of cows grazing the control pasture was 280 {\textpm} 30 nmol/L, while in cows grazing pasture treated with the Sel Se prill blood Se concentrations increased to 1364 {\textpm} 112 nmol/L after 372 days. In the case of cows grazing pasture treated with Rav Se prill, blood Se concentrations increased to 1192 {\textpm} 66 nmol/L within 60 days, before decreasing slowly to 740 {\textpm} 65 nmol/L at 372 days. Blood glutathione peroxidase activity followed a similar pattern to the blood Se. The mean serum Se concentrations of the untreated cows was 151 nmol/L, while in animals on the Sel Se prill-treated pasture they reached a small peak at Day 64, followed by a decrease and then continued to increase to 675 nmol/L at Day 372. In contrast, for cows on the Rav Se prill treatment the serum Se concentrations reached a peak of 920 nmol/L at Day 64, and then decreased to 263 nmol/L at Day 372. Milk Se followed a similar pattern to serum Se. Selenium-amended fertilisers were found to be effective in raising the pasture Se concentrations for 4 or 12 months, depending on Se prill composition, which then in turn increased blood Se concentrations of dairy cows for at least 12 months. }, issn = {1176-5283}, author = {Grace ND and West DM} } @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 {41560, title = {Does ewe nutrition during pregnancy affect the metabolism of twin-born lambs?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {163-167}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {An insulin tolerance test was conducted on twin-born ewes born to dams offered sward heights of either 2 or 6 cm between day 64 and 132 of pregnancy in order to identify any alterations in the lamb{\textquoteright}s metabolism. Lambs were also categorised into groups according to birth weight (< 4.0 kg, light and > 4.0 kg, heavy). Changes in metabolism may have long term effects on growth and productivity. An insulin challenge (0.2 U/kg) was administered to ewe lambs at 8 months of age and their plasma insulin, glucose and cortisol responses were monitored. The plasma cortisol concentration of ewe lambs born to ewes offered 2cm sward height was significantly (P < 0.05) higher than ewe lambs born to ewes offered 6 cm sward height 50 minutes after the insulin challenge. No difference was found in the insulin or glucose response to the insulin challenge between dam sward height group (2 vs 6 cm). Birth weight had no effect on the insulin, glucose or cortisol response of the ewe lambs to the insulin challenge. These results show that both dam nutrition and lamb birth weight had little to no effect on the metabolic responses measured. These results suggest that lambs born to ewes offered a herbage sward height of only 2 cm or lambs with low birth weights may not show altered metabolism. KEYWORDS: lamb; insulin tolerance test; twins; ewe nutrition; metabolism. }, issn = {1176-5283}, author = {Corner RA and Kenyon PR and Stafford KJ and West DM and Oliver MH and Morris ST and Blair HT} } @conference {41532, title = {Does the ewe nutrition during pregnancy affect the behaviour of ewe lambs at 1 and 2 years of age?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {29-32}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {The effects of the dam{\textquoteright}s nutrition during pregnancy on her lambs{\textquoteright} behaviour in the days after birth has been examined but the longer term effects on lamb behaviour and mothering ability are not known. The behaviour of twin and triplet ewes born to ewes offered herbage with an average sward height of 2 or 6 cm from day 64 to 132 of pregnancy was recorded at 1 year of age in an arena test and at 2 years of age post lambing. A significantly (P < 0.05) greater proportion of the progeny born to dams offered 6 cm sward heights bleated in a high pitch during a 5 minute arena test. However there were no differences in minimum, median and maximum distance of the ewe from the observer or on the frequency of low- and high-pitched bleats. In addition there was no difference in the behaviour of twin- and triplet-born ewes in the arena test. At 2 years of age twin-born ewes had a significantly greater maternal behaviour score than their triplet-born counterparts. Ewe nutrition during pregnancy did not affect the maternal behaviour score of their ewe lambs after lambing at 2 years of age. These results suggest that feeding levels during pregnancy are less important than the birth rank in terms of the intergenerational effects on behaviour. KEYWORDS: ewe nutrition; lamb; behaviour; twin; triplet. }, issn = {1176-5283}, author = {Corner RA and Kenyon PR and Stafford KJ and West DM and Morris ST and Blair HT} } @conference {41508, title = {Hogget mating in New Zealand - a survey}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {217-222}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Currently less than 30\% of all hoggets are presented for mating in New Zealand. This would suggest that there are a number of disadvantages to this management practise. However to date it has not been accurately established what farmers perceive as the disadvantages of hogget mating and the relative importance of each of these disadvantages. A questionnaire was sent to New Zealand sheep farmers which asked a series of questions regarding farm type, size, farm class, flock type, flock size and the intended use of hogget mating in 2002 and its use in the past. Those farmers who were not intending to mate hoggets in 2002 were also asked to indicate the importance, on a scale of 1.4, of 11 stated reasons for not hogget mating. A total of 1981 questionnaires were returned and used in the present study from a total of 14,000 sent to farmers. Descriptive analysis indicated negative effects on two-tooth performance and lack of additional feed were the two main reasons for not mating hoggets. The least important variables were lack of experience and the need for extra rams/teasers. The intended use of hogget mating differed based on farm class, farm size, ewe flock size and farm and flock type. Farmers were more than twice as likely to mate hoggets in 2002 if they had a mixed-bred flock in comparison to a straight-bred flock and more than twenty times more likely to mate hoggets in 2002 if they had mated hoggets in previous years. This study indicates that farmers perceive impaired two-tooth performance as a major reason for not hogget mating, even though research to date would indicate this is not that case. Therefore either improved technology transfer is required or the effects of hogget mating on two-tooth performance need to be re-visited. }, issn = {1176-5283}, author = {Kenyon PR and Morris ST and Perkins NR and West DM} } @conference {41499, title = {Manipulating lamb birth weight and survival rate in singletons born to hoggets}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {175-178}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Lambs born to hoggets tend to be relatively lightweight at birth (Drymundsson, 1973; McMillan \& McDonald, 1983) and display low survival rates to weaning (McCall \& Hight 1981; McMillan \& McDonald, 1983). In addition the incidence of singletons in hoggets often exceeds 92\% (McCall \& Hight, 1981; McMillan \& McDonald, 1983). Therefore management procedures that improve both birth weight and survival of singleton lambs should have a significant effect on returns. Severe under nutrition during pregnancy of mature ewes can lead to reduced ewe and lamb performance (Rattray 1986), which can negatively affect lamb survival. However to date minimal research under New Zealand{\textquoteright}s pastoral conditions has been undertaken in hoggets. In contrast to the mature ewe, it is also advantageous for the hogget to be increasing in conceptus-free live weight during pregnancy if lifetime performance is not to be negatively affected. Interestingly, under concentrate feeding regimes in the United Kingdom it has been reported that a high level of hogget nutrition in pregnancy, actually reduces both lamb birth weight and survival (Wallace et al., 1996). Shearing mature ewes in mid- to late-pregnancy has been shown to differentially increase singleton- (Morris et al., 2000; Kenyon et al., 2002a) and twin-lamb birth weights (Morris \& McCutcheon, 1997; Morris et al., 1999; Kenyon et al., 2002b). Mid-pregnancy shearing has tended to increase twin-lamb survival rates (Morris et al., 1999; Kenyon et al., 2002b) but has been found to decrease singleton survival rates in one of four studies (Kenyon 2002). The effect of mid- to late-pregnancy shearing of hoggets has not been examined under pastoral conditions in New Zealand. Due to the low rate of twin pregnancies in hogget{\textquoteright}s the chance of achieving a positive affect from mid-pregnancy shearing on both a lamb birth weight and survival may be low. The aims of these studies were to determine if hogget live weight change and shearing treatment during pregnancy could be used to manipulate singleton lamb birth weight and survival. }, issn = {1176-5283}, author = {Kenyon PR and Morris ST and West DM and Stafford KJ and Corner RA and Ottema K and Burnham DL} } @conference {41368, title = {Johne{\textquoteright}s Disease - Why Johne{\textquoteright}s disease is so difficult to control}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {282-283}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Johne{\textquoteleft}s disease caused by infection with Mycobacterium avium subspecies paratuberculosis affects New Zealand cattle, sheep, goats and deer. The disease is difficult to control because of the long incubation period, the long survival of the organism in the environment, shedding by apparently healthy but infected animals and the unreliability of diagnostic tests to detect subclinical or even clinical disease. A brief contrast with the approach to control in New Zealand and Australia is made

}, issn = {1176-5283}, author = {West DM} } @conference {41378, title = {Predicting copper status of cattle remains an engima}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {319-324}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Data are presented from several studies carried out by AgResearch and Massey University describing scenarios that affect the Cu status of grazing cattle. In all these studies, complex interactions between Cu, Fe, Mo and S make it difficult to predict Cu status. Increasing pasture Mo reduced percent absorption of dietary Cu in sheep by half (from 4.6\% down to 2.6\%). In contrast, the Cu kinetics in cattle could not be similarly simplified, so more sophisticated modelling calculations need to be applied. Even with moderate Mo intake (i.e. from pasture 0.8 mg Mo/kg DM), liver Cu content was quickly depleted in the cattle, reaching a low but stable level of 8 mg Cu/kg DM that appears to be a Mo-insensitive liver Cu store. In other trials, various Cu supplementation strategies have produced considerable but unexpected responses in liver Cu content. The risks and benefits of using liver Cu concentrations as an index of Cu status, and whether a multi-variable approach using tissue biomarkers, animal physiology, diet composition, and time of exposure is what is required to accurately predict the future Cu status for cattle are discussed.

}, issn = {1176-5283}, author = {Lee J and Knowles SO and West DM} } @conference {41369, title = {Subclinical Johne{\textquoteright}s Disease in Sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {284-287}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

This paper presents preliminary results from a 5-year study aimed at generating objective data on the effect of subclinical Johne{\textquoteleft}s disease on productivity in sheep. On two properties where Johne{\textquoteleft}s disease was considered to be a problem, replacement ewe lambs from a single generation were allocated to one of three groups. One group was vaccinated with the killed Mycobacterium avium subsp. paratuberculosis vaccine Neoparasec, another with the live vaccine Gudair, and the other group remained as unvaccinated controls. The vaccinated and control ewes were monitored over the ensuing four years for the following parameters: lesion size, live weight, fleece weight, scanning percentage, lamb production and weight of lambs weaned per ewe. Serology was also performed on a sample of animals from each group. On one property, the size vaccination-site lesions associated with Gudair declined at a more rapid rate than those associated with Neoparasec. However, results to date have failed to detect a significant difference in productivity between vaccinated and unvaccinated ewes in either flock, suggesting that subclinical Johne{\textquoteleft}s disease may not be an important cause of production loss in sheep. The trial is now in its final year.

}, issn = {1176-5283}, author = {Thompson KG and West DM and Anderson PVA and Burnham DL} } @conference {41101, title = {Attempted Transmission of Brucella ovis between stags and from stags to rams}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {134-136}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {In August 1997 three 9-month-old Red x Wapiti stags were inoculated intravenously with Brucella ovis. Between October 1997 and June 1998 these three stags were grazed with 8 control stags of a similar age and 10 one-year-old Perendale rams, which had been confirmed free from B. ovis infection before mixing. At monthly intervals the 11 stags and 10 rams were blood sampled for B. ovis serology and when infection was suspected, this was confirmed by bacterial culture of a semen sample. Two of the three artificially infected stags became persistently infected with B. ovis and shed the organism in their semen. They remained positive to the B. ovis complement fixation (CF) serological test throughout the trial. The CF titre fell below the positive cut-off level 4 months after inoculation in the other artificially infected stag which did not develop persistent B. ovis infection. During April and May 1998, 7 months after mixing with the artificially infected animals, B. ovis infection was identified in 4 of the 8 control stags. There was no evidence of B. ovis transmission to the control rams. The trial demonstrated the rapid transmission of B. ovis infection between young stags during the rut. This would suggest that sexual activity is important for B. ovis to spread, although the exact means of transmission could not be determined. Rams grazed in conjunction with B. ovis - infected stags have a lower risk of becoming infected. }, issn = {1176-5283}, author = {West DM and Stafford KJ and Sargison ND and Fenwick SG and Reichel MP} } @conference {41028, title = {Iodine deficiency: an emerging problem in New Zealand sheep flocks.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {202-204}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Iodine supplementation before mating had a significant positive effect on ewe fertility in a Manawatu Romney flock, with 14\% more lambs born to supplemented than to control mixed aged ewes. The survival of newborn lambs was enhanced in the iodine-supplemented group when compared with the control group, accompanied by a significant difference between the thyroid:body weight ratios of dead newborn lambs in the supplemented and control groups (0.28 and 0.48 g/kg respectively)(p=0.005). During the spring of 1997, high perinatal lamb mortality rates (25\%, 50\% and 66\%), despite favourable lambing weather conditions and adequate ewe nutrition throughout pregnancy, were investigated in three other Manawatu sheep flocks. The mean lamb thyroid:body weight ratios of dead newborn lambs were greater than 0.4 g/kg and hyperplastic colloid goitre was identified histologically. Goitrogens in the pasture were believed to be an important predisposing factor. Modern varieties of white clover present in New Zealand pastures contain extremely high concentrations of thiocyanate goitrogen precursors, therefore, iodine deficiency may be an emerging problem. }, issn = {1176-5283}, author = {Sargison ND and West DM} } @conference {40051, title = {Effectiveness of the New Zealand brucellosis control scheme for sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {47}, year = {1987}, month = {Jan}, pages = {49-51}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Three trials were completed using 1813 cows in seasonal dairy herds to study the effects of an injection of a prostaglandin F2alpha, dinoprost tromethamine (Lutalyse}, issn = {1176-5283}, author = {Bruere AN and West DM} }