@conference {41800,
	title = {Effect of dry cow management on teat end bacterial contamination},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {92-95},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Two stock management practices were investigated for their effect on transfer of bacteria from the environment onto teat ends of dry dairy cows. Cows (n = 20) were required to walk or trot along races (1.2 km) deemed to be "clean" or "dirty". Cows walked along "clean" or "dirty" races were similar in dirtiness of the udder, and bacterial loading of the teats. Cows that trotted along {\textquoteleft}dirty{\textquoteleft} races showed a significant increase in degree of dirtiness of the teats and legs, and increased contamination of teats with coliform bacteria. Cows grazed for 24 hour periods using standard break-fencing systems, with (n = 20) or without (n = 20) the addition of back-fencing were assessed for the number and type of bacteria present on teat-ends. Cows that grazed paddocks with back-fencing had visually dirtier udders, but there was no difference in bacterial contamination of teats compared to those cows grazed without back-fencing. These studies suggest that the risk of bacterial contamination, and by extrapolation, risk of intra-mammary infection, may be mitigated by the speed with which cows are moved along races. However, grazing on muddy, soiled paddocks should not be discounted as a significant risk factor for mastitis. },
	issn = {1176-5283},
	author = {Turner S-A and Williamson JH and Lacy-Hulbert SJ}
}
@conference {41748,
	title = {Teat spraying before calving and Streptococcus uberis clinical mastitis in heifers : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {312-314},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Mastitis caused by the environmental pathogen Streptococcus uberisis a significant problem for New Zealand dairy farmers. Previous work on teat-spraying heifers three times a week for three weeks prior to calving demonstrated that a decrease in S. uberisteat-end contamination reduced the proportion of quarters infected with S. uberisat calving. This study evaluated the effect of teat-spraying heifers in the dry period for its ability to reduce S. uberisclinical mastitis (CM) after calving. Heifers from five commercial dairy herds (n=343) and one research farm (n=54) were enrolled to the study. Half of the animals from each herd were assigned to a Sprayed and the other half to a Not Sprayed group. Both groups were brought to the dairy three times a week, beginning three weeks prior to predicted calving dates and heifers in the Sprayed group were teat-sprayed with a commercially available iodine-basedteat sanitizer. Cases of CM that occurred in the  week after calving were sampled and submitted for bacteriological analysis. Incidence of S. uberisCM was 50\% lower in the Sprayed, affecting 3.6\% heifers vs. 7.4\% heifers of the Not Sprayed group (P=0.085). There was an indication that teat-spraying heifers three weeks prior to calving may have positive benefits in the reduction of CM caused by S. uberisafter calving.},
	issn = {1176-5283},
	author = {Lopez-Benavides MG and Williamson JH and Lacy-Hulbert SJ}
}
@conference {41905,
	title = {Mastitis in cows milked in an automated or conventional milking system in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {252-257},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {The viability of automated milking systems (AMS) for pasture-based dairying has been studied in New Zealand in the past four years. Automatic milking differs from conventional milk harvesting systems (CMS) in a number of ways, which may impact on udder health. These include fewer machines/cow, distributed vs. batch milking, variable milking intervals, automatic udder health monitoring systems, and pre and post-milking teat sanitation procedures. Three seasons of data from two pasture-based research farms that milked cows with either a two unit AMS or a 30 bail rotary CMS were compared. Quarter milk samples were collected routinely from all cows for bacteriological analysis during the 2002-03, 2003-04 and 2004-05 seasons, with sampling occurring throughout lactation and at detection of clinical mastitis (CM) cases. The number of cows in the AMS herd ranged from 94 to 196 and in the CMS herd, from 289 to 324 across the seasons. Clinical mastitis affected 7, 11, and 15 cows/100 cows/season in the AMS herd and 24, 23 and 14 cows/100 cows/season in the CMS across the three seasons, with Streptococcus uberis isolated from approximately 50\% of CM cases from both herds. Prevalence of S. uberis post-calving averaged 8\% of cows for the AMS and 16\% for the CMS across the three seasons. We compared several indicators of udder health between an AMS and a CMS herd managed under pastoral conditions. },
	issn = {1176-5283},
	author = {Lopez-Benavides MG and Williamson JH and McGowan JE and Lacy-Hulbert SJ and Jago JG and Davis KL and Woolford MW}
}
@conference {41650,
	title = {Prevalence of mastitis for cows of different genotypes milked for two consecutive seasons},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {236-240},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Extending the calving interval from the traditional 12-month to a 24-month calving interval has been suggested as a practical solution for maximizing lactation yield per calving. Somatic cell count (SCC) and the incidence of mastitis were examined in New Zealand (NZ) and overseas (OS) Holstein-Friesian cows fed on pasture alone or supplemented with 3 or 6 kg DM maize/barley concentrates/cow/day during an extended lactation of up to 21 months. Average cow SCC was three-fold higher (P<0.001) in the extended or second season of the lactation compared with the first season, with NZ cows having a slightly higher SCC (P<0.01) in the second season compared to OS cows (191,000 and 115,000 cells/ml respectively). The SCC elevations occurred regardless of infection status of the udder. Although OS cows tended to have twice as many cases of clinical mastitis (P=0.01) in the first season compared to the NZ cows, affecting 59\% and 27\% of cows respectively, there was no difference in infection status between genotypes in the second season (20\% and 18\% respectively). Results showed that although cows experienced less mastitis during the second spring of the lactation, the average cow SCC was higher during the extended part of the lactation. },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Summers EL and Williamson JH and Aspin PW and Kolver ES}
}
@conference {41888,
	title = {Teat spraying prior to calving may reduce the risk of heifer mastitis caused by Streptococcus uberis},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {168-171},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Heifer mastitis caused by Streptococcus uberis is a significant problem for New Zealand dairy farmers. The mechanisms of infection in the pre-partum period have not been fully elucidated but prior research has established that the teats of dairy cows are contaminated with significantly higher numbers of S. uberis during the dry period as compared to during lactation. It is hypothesised that gross teat-end contamination by these bacteria before calving is a significant risk factor for the entry of bacteria through the teat canal and establishment of infection. Regular disinfection of the teats in the dry period was evaluated as a means to reduce teat-end contamination and consequently to decrease the likelihood of glands developing an infection. Two groups of 27 heifers were assigned to either a {\textquoteleft}sprayed{\textquoteright} or {\textquoteleft}not-sprayed{\textquoteright} treatment. The sprayed heifers were teat-sprayed with a commercial iodine-based post-milking teat sanitizer three times a week for the last three weeks before calving. Before commencement of the experiment, teat-ends were swabbed to determine pre-existing contamination with S. uberis, which averaged 610 colony-forming units (cfu). Prior to calving, S. uberis counts on teat-ends were 560 cfu for the sprayed group and 1775 cfu for the non-sprayed group (p = 0.06). Bacteriology of milk from each gland at the first milking showed that 4\% of glands of the sprayed heifers were infected with S. uberis compared with 11\% for the non-sprayed heifers (p < 0.05). At the first herd test, heifers in the sprayed group had a lower SCC (380,000 cells/ml) compared to the non-sprayed group (790,000 cells/ml), although due to the small size of the study, this difference was not significant. It was concluded that teat-spraying in the dry period could reduce teat-end contamination and consequently the proportion of glands infected by S. uberis at calving. },
	issn = {1176-5283},
	author = {Lopez-Benavides MG and Williamson JH and Lacy-Hulbert SJ and Cursons RT}
}
@conference {41555,
	title = {The effects of once a day milking on mastitis and somatic cell count},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {137-142},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A four-year study examined the effect of once a day (OAD) milking for complete lactations on mastitis and milk quality. The study comprised two herds of Jersey cows and two of Friesian cows, milked either OAD or twice a day (TAD) for a total of 4 lactations. Prevalence of intramammary infection (IMI) was determined by isolation of mastitis pathogens from quarter foremilk samples, collected aseptically at calving, mid lactation and at drying off. In the second and third years of the study, at drying off, cows milked OAD had three times as many (P < 0.01) quarters with IMI by major mastitis pathogens compared with TAD cows. Across all pathogens and years however, prevalence of IMI was not significantly or consistently higher for cows milked OAD compared with TAD. The somatic cell count (SCC) for uninfected cows milked OAD was approximately double that for TAD milked cows although this difference was only significant (P < 0.05) after the first 1-2 months of lactation had elapsed. Cows with minor or major pathogen infections also showed an approximate doubling of the SCC if milked OAD. Results suggest that milking OAD consistently increases the individual cow SCC but does not significantly increase prevalence of mastitis.
KEYWORDS: once daily milking; mastitis; SCC; milk quality; milking frequency. },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Dalley DE and Clark DA}
}
@conference {41470,
	title = {Influence of feeding level after drying off on incidence of mastitis and keratin plug formation in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {48-52},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Prolonged postpartum anoestrous intervals (PPAI) are the major source of infertility in New Zealand dairy cows.  Postpartum supplementation with mono propylene glycol (MPG) was previously shown to reduce PPAI in heifers. The  present experiment tested this treatment in four large commercial dairy herds. During the six-week period preceding the  planned start of mating (PSM; week 0), cows were drenched either once (1xMPG) or twice (2xMPG) daily with 200 ml  MPG, or served as untreated controls (CON). Analyses were confined to the group of cows that were anoestrus at Week  {\~n} 6 or calved between Week {\~n} 6 and Week -4 relative to PSM (n = 662 to 669 per treatment). Change in body condition  score between Week {\~n} 6 and Week - 1(∆BCS), and proportion of cows that were anoestrus at Week {\~n}1 were influenced  by herd, age and time of calving (P<0.05) but not by treatment (P>0.1). Treatment did not influence the proportion of  anoestrous-treated cows inseminated after oestrus detection (n =263), or the pregnancy rate among all cows. Pre-mating  supplementation with MPG did not influence ∆BCS, the percentage of cows that were anoestrus at Week {\~n}1, or rates of  submission and conception. Change in BCS affected both milk yield and pregnancy rates, where cows that gained BCS  produced less milk but showed higher 6-week pregnancy rates. This study highlighted that key factors influencing the  percentage of anoestrus at PSM are cow age, time of calving and management of the herd. 

},
	issn = {1176-5283},
	author = {Summers EL and Lacy-Hulbert SJ and Williamson JH and Sugar BP}
}
@conference {41323,
	title = {Effect of udder health on milk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {95-99},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Mastitis is an inflammation of the udder tissue, normally arising from a bacterial infection. The effects of mastitis on the processing properties of milk have been widely researched over the past 40 years. This paper summarises the main effects of udder health on raw milk composition and its processing properties, reviews the progress made to date by the New Zealand dairy industry with regard to reducing the impact of mastitis on milk processing, and highlights continuing avenues of enquiry.},
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Auldist MJ}
}
@conference {41306,
	title = {Incidence of mastitis among cows of different genogtypes in differing nutritional environments},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {24-29},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Over three seasons (1998, 1999 and 2000) groups of Holstein-Friesian cows of New Zealand (NZ) or overseas (OS) origin were monitored for mastitis when managed in two contrasting systems. Cows were fed either on pasture or total mixed ration (TMR) with cows on TMR confined to small loafing paddocks or a concrete feedpad. All quarters were sampled for bacteriology at calving, at dry off, in mid and late lactation and when clinical mastitis was detected. Individual cow somatic cell counts (SCC) were determined weekly throughout lactation. In 1998, there was no difference in incidence of clinical mastitis but in later seasons, cows on TMR experienced significantly more clinical, and sub-clinical mastitis, than cows on pasture, probably reflecting differences in bacterial challenge within the environment. Genotype differences were less evident compared to dietary effects. Compared to NZ cows, OS cows experienced more sub-clinical infections in 1998 and more clinical infections in 1999 whilst in 2000, genotype effects were confounded by diet. Seasonal SCC was higher for OS cows in 1999 and 2000, reflecting differences in incidence of sub-clinical mastitis among treatment groups. Despite the strong influence of environment on mastitis incidence, genotype differences were detectable between NZ and OS cows. },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Kolver ES and Williamson JH and Napper AR}
}
@conference {41119,
	title = {Sealing of the bovine teat canal after dry-off.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {198-200},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Closed teats have proven more resistant to dry period mastitis than open teats. Natural rate of keratin plug formation within closed and open teats, and consequences of bacterial colonisation of the teat canal, were examined using 67 low somatic cell count cows. Cows were dried off without antibiotic therapy and teats assessed for closure status at 5, 10, 15 and 20 d after drying off. Weight and bacteriological status of the keratin plug was determined by reaming teats with a sterile pre-weighed tapestry needle 7 d prior to drying off and on one occasion post drying off. Initially (d 5), keratin weight for all teats increased by 100\% compared to lactating teats (4.89 mg/qtr). Between d 10-20, keratin weight from open teats (29\% of teats) was 34-55\% less than for closed teats. Subclinical infections in the teat canal significantly reduced likelihood of teats closing after drying off. },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Williamson JH and Day AM and Woolford MW}
}
@conference {40780,
	title = {Effect of Streptococcus uberis infection on milk characteristics of individual quarters},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {65-67},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Composite 24 h milk samples were collected for detailed milk analysis  from each quarter of ten cows known to be free of intramammary infection.  Milk yield and concentration of lactose and serum albumin (BSA) were  significantly higher (P<0.001), and chloride ions significantly lower  (P<0.001), in hind compared with fore quarters. Four cows developed  clinical intramammary infection when subsequently challenged in the left  hind quarter with Streptococcus uberis. For all parameters measured, i.e.  protein, lactose, somatic cell count (SCC), BSA and immunoglobulins  (IgG), milk from the infected quarter differed significantly from the  uninfected quarters. No effect of infection was observed in quarters adjacent  to the infected quarter, except for SCC, which increased significantly  (P<0.001) in the uninfected hind quarter. Milk proteolytic activity in the  infected quarter increased significantly (P<0.001) due to increased  conversion of plasmin to plasminogen.},
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Woolford MW and Nicholas G and Stelwagen K}
}
@conference {40831,
	title = {Reduction in SCC and colostrum levels in milk after calving},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {263-265},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Somatic cell count (SCC) and immunoglobulin G1 (IgG1) content  were determined in mammary secretions of 15 Friesian x Jersey cows and 5  heifers at each milking for 10 d following natural calving. Milk yields for  cows on d 1 were 20.2 l/d, declined sharply on d 2 to 14.4 l/d, then increased  slightly, reaching 17.9 l/d by d 10. In contrast, heifer milk yields were low  on d 1 (6.6 l/d) but increased steadily to 11.9 l/d by d 10. The SCC and IgG1  levels were extremely high on d 1 (1.50 x106 cells/ml and 24.0 g/l IgG1) but  declined rapidly within 48 h of calving. Average SCC and IgG1 reduced  below the penalty levels by d 4 for cows, and d 5 for heifers, confirming that  milk should be withheld from the bulk tank for 4 d and 5 d after calving for  cows and heifers respectively. Individual cows may exceed these levels for  short periods.},
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Malcolm DB and Copeman PJA and Woolford MW and Franks R}
}
@conference {40651,
	title = {Influence of milking frequency and feeding level on plasmin activity and casein degradation in milk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {9-11},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Wool samples from 28 Merino wethers, 31 Corriedale ewes, 37  Perendale ewes and 30 Coopworth ewes were examined for propensity to  develop yellow discolouration in relation to the mean fibre diameter and  its variability.    The propensity of wool to develop yellow discolourations was estimated  by two techniques, namely, an incubation technique which measures the  colour developed in the wool fibre during an incubation in the  laboratory, and the predictive technique described by Aitken et  al., 1994.    Correlations between propensity to yellow (Y-Z) and mean fibre diameter  were low in the Corriedale, Perendale and Coopworth samples, but high in  the Merinos. Correlations between propensity to yellow and standard  deviation of fibre diameter were also low in the Corriedales, Perendales  and Coopworths, but moderate in the Merinos. The correlations between Y  and Z and the fibre diameter statistics following similar trends to  those for Y-Z.    All correlations between propensity to yellow and coefficient of  variation of fibre diameter were low.    Thus while the propensity to discolour during growth is positively  related to fibre diameter in fine wool, no such relationship exists in  medium and coarser wool. This provides a further reason for Merino  breeders to produce a fine fleece type.   },
	issn = {1176-5283},
	author = {Prosser CG and Nicholas G and Stelwagen K and Lacy-Hulbert SJ and Woolford MW and McFadden TB}
}
@conference {40676,
	title = {Influence of once daily milking and restricted feeding on milk characteristics in late lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {85-87},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Ninety 1991 drop Merino wethers, thirty from each of fine, medium   and strong wool strains were randomly allocated on the basis of stratified  live   weight within strains to one of three treatment groups. The first treatment   involved grazing ample good quality natural or irrigated pasture (H)   throughout the experiment so that the sheep remained in good to excellent   condition throughout. The second involved grazing restricted amounts of   pool quality nature pasture (L) throughout the experiment so that the sheep   remained in backward store condition. As a control, a third group (C) grazed   natural pasture such that the sheep subject to seasonal variations in pasture   quality and quantity and their condition varied from store to forward store   throughout the experiment.    Intake was estimated on two occasions; in February 1994, and July 1994, by   dosing with controlled-release alkane capsules. Pasture samples were taken   at these times based on observation of sheep grazing patterns. However,   later analysis showed that the pattern of alkanes in the collected herbage was   different to the alkane pattern in faecal samples, indicating that the herbage   samples were not truly representative of the herbage consumed by the sheep,   particularly at the summer sampling.    Actual intake (AI) (expressed as kgOM/day },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Woolford MW and Bryant AM}
}
