@conference {40990,
	title = {Growth curves and productivity of Holstein-Friesian cows bred for heavy or light mature live weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {68-72},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This paper presents data for live weights (LW) from birth to maturity, and for yields of milk and milksolids (MSY) per lactation, from two lines of Holstein-Friesian cows bred for heavy (H) or light (L) mature LW. Compared with the Brody, Gompertz and Logistic functions, the Von Bertalanffy function provided the best fit to the LW data, and prediction from this function has been used in the following analyses. The breeding values (BV) for LW of the sires (H: 86.3 kg; L: 31.0 kg) and maternal grandsires (MGS) (H: 55 kg; L: 38 kg) used to develop the H and L LW lines were higher (P<0.001) for the H line than for the L line, and they were significantly associated with the actual birth weight (H: 41 kg; L: 35 kg) and mature live weight (H: 520 kg; L: 467 kg) of the cows. The heavy sires also had significantly higher BV for yield of milk (H: 1037 l; L: 737 l), milkfat (H: 33.0 kg; L: 27.5 kg), and milk protein (H: 31 kg; L: 22 kg), and the H cows produced more milk (H: 4708 l; L: 4323 l), and MSY (H: 364 kg; L: 348 kg) than the L cows. However, L sires had slightly higher (P = 0.07) value for Breeding Worth than the H sires (H:37; L:46), and there were only small differences in yields of milk or MSY between the two lines when these were expressed per kg of LW, per kg of LW0.75 or per tonne of dry matter required (H: 84 kg MSY/tonne DM; L: 87 kg MSY/tonne DM). The results indicate that the extra MSY by the H cows (+ 16 kg) almost compensated for the effect of their extra LW (+ 46 kg), so that the H cows were only slightly less efficient than the L cows, as predicted by their respective sire{\textquoteright}s Breeding Worth. },
	issn = {1176-5283},
	author = {Garcia-Muniz JG and Holmes CW and Garrick DJ and Lopez-Villalobos N and Wickham BW and Wilson G and Brookes IM and Purchas RW}
}
@conference {40884,
	title = {Growth and onset of puberty in two genetically different lines of Holstein-Friesian cows, selected for either heavy or light body weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {46-47},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Heavier body weight affects dairy farm profitability through its effects on extra dietary energy requirements for maintenance and growth and on extra income from culled cattle; therefore it is now included in the new Animal Evaluation System used with New Zealand dairy cattle. The selection of two lines of Holstein-Friesian cattle began in 1989 using proven sires with either high (H) or low (L) estimated breeding value (EBV) for live weight (LW), but which were all of high genetic merit for milk solids yield. This paper reports on the onset of puberty and the pattern of growth from birth to first calving of heifers from these two genetic lines of cattle.},
	issn = {1176-5283},
	author = {Garcia-Muniz JG and Holmes CW and Wickham BW}
}
@conference {40766,
	title = {Associations between milk protein genetic variants and production traits in New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {24-27},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Records on 7574 first lactation cows were used to investigate the  associations between milk protein genetic variants and 305-day milk, fat,  and protein yields. Friesians, Jerseys and Ayrshires and their crosses were  represented in the data. Milk samples were typed for 3 casein (CN) proteins  as1-CN (B,C), b-CN (A1, A2), k-CN (A,B) and 1 whey protein b- lactoglobulin (LG) (A,B). The model used to describe the data included the  additive genetic effect of animal and the four protein phenotypes. The interaction between breed and as1-CN phenotype and between breed  and b-CN phenotype was significant (P<0.05) for milk, fat and protein  yields while the interaction between breed and k-CN phenotype was  significant (P<0.05) only for protein yield. The interactions associated with  the as1-CN and k-CN phenotypes were scale effects while the interactions  associated with b-CN resulted from reranking of protein phenotype across  the breeds. Friesian and Jersey as1-CN BB cows had higher (2.8\% and  0.8\%, respectively) milk production and lower (0.3\% and 1.2\%,  respectively) protein production than BC animals while the differences  between the phenotypes for fat production were small. The b-CN A2 allele  was associated with increased production in the Friesians with A2A2 cows  producing approximately 2\% more milk, fat and protein than A1A1 cows.  The opposite effect was found in Jerseys where A2A2 cows produced 3-4\%  less milk, fat, and protein than A1A1 cows. The B allele of k-CN was  associated with a 0.6 to 3.5\% increase in production. The b-LG BB  phenotypes produced approximately 1.3\% less milk and protein and 1.2\%  more fat than the AA phenotypes. The dominance effect was not significant  (P<0.05) for any of the protein phenotypes. },
	issn = {1176-5283},
	author = {Winkelman AM and Wickham BW}
}
@conference {40618,
	title = {Effects of once daily milking in late lactation on cows with either low or high initial somatic cell counts},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {285-288},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The present study was carried out in order to measure the effects of  
once daily milking on somatic cell count (SCC) of cows which had either low 
SCS  
or high SCC at the start of the experiment in late lactation.  Thirty six cows  
were used, 18 with low SCC and 18 with higher SCC.  Nine cows from each  
group were randomly allocated to once or twice daily milking for the four week  
experimental period in March.  The yields of milk, fat, protein and lactose were  
significantly reduced by once daily milking (P<0.01) in both groups.  However,  
the effects of once daily milking on yields was larger for high SCC cows  
(interaction P<0.01).  Once daily milking significantly increased the  
concentration of protein (P<0.001) in both groups and fat (P<0.01) in only the  
low SCC group.  Once daily milking significantly reduced the concentration of  
lactose, the effect being larger in the high SCC group (interaction P<0.001).   
SCC (per ml) was increased by once daily milking, but the effect was  
significant only in the high SCC group (interaction P<0.10).  The total number  
of cells produced per day were not affected by once daily milking. 
 
These results show that SCC can be used with confidence to identify  
subclinically infected cows in later lactation milked once or twice a day.  The  
results also show that cows with a low incidence of subclinical mastitis can be  
milked once daily in later lactation, with much less effect on yield of milk and  
its constituents than would be expected in cows with a higher incidence of  
infection. },
	issn = {1176-5283},
	author = {Kamote HI and Holmes CW and MacKenzie DDS and Holdaway RJ and Wickham BW}
}
@conference {40316,
	title = {Plasma hormone concentrations in pasture-fed Friesian cows treated with recombinantly-derived bovine somatotropin (bST)},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {235-238},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Dairy farmers often debate the importance of liveweight of  rising 2 year old heifers and the value of various heifer wintering  systems on subsequent production. Lifetime performance of all dairy  cows born on the Taranaki Agricultural Research Station have been  recorded since 1978 on a computerised data base. This data base was  utilised to determine the liveweight gain of heifers and cows over  winter and the effects of this on production in the following season.   Initial analysis of the data showed a significant (P<0.01) age effect on  winter liveweight gain within a mixed age herd of cows. The average  liveweight gain over eight years of the older cows (4 yr +) was 3 times  that of the rising 2 year olds. Further analysis showed a significant  (P<0.05) age effect on the relationship between liveweight at calving  and production of milkfat in the following season. Higher liveweight at  calving resulted in a greater increase in production for 2 year olds  than for older cattle. The conclusion to be drawn from this is that  wintering rising 2 yea old heifers separately from older cows to achieve  higher liveweight may have beneficial effects on the following seasons  production.   A field trial in winter 1990 to test this assumption showed the winter  liveweight gain of rising 2 year old heifers and mature cows, offered  the same herbage allowance, was significantly (P<0.01) higher when  wintered separately than wintered as a mixed age herd. Subsequent milk  solids production from the two-wintering systems was the same despite  different liveweight at calving. Aspects of herd behaviour were  suggested as the cause of the nil response.  },
	issn = {1176-5283},
	author = {McCutcheon SN and Hoogendoorn CJ and Lynch GA and Wickham BW and Breier BH and Gluckman PD}
}
@conference {40216,
	title = {The future impact of new opportunities in reproductive physiology and molecular biology on genetic improvement programmes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {197-210},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {During the serious outbreak of facial eczema (FE) in 1989, blood   samples were obtained from first-lactation heifers born in 1986, in   order to study any genetic influence on the incidence of FE. Heifers   were located in 60 herds in Northland (14 herds), Auckland (25) and   Taranaki (21). The herds were members of the New Zealand Dairy Board{\textquoteright}s   1985 Sire Proving Scheme for young Jersey bulls. Samples were collected   from 1523 heifers, the daughters of 57 young Jersey sires and 19 other   Jerseys including reference sires from previous years. Blood samples   were analysed for gamma-glutamyltransferase (GGT), an indicator of liver   damage such as due to FE. Overall, 28\% of animals had elevated GGT   values (>=30IU/1), and 72\% (43) of herds had 2 or more animals with   elevated GGT. After setting aside data from the 17 herds where no   elevations of GGT concentration were recorded, the heritability of log e   GGT was 0.31},
	issn = {1176-5283},
	author = {Baker RL and Shannon P and Garrick DJ and Blair HT and Wickham BW}
}
@conference {40090,
	title = {Factors affecting AB conception rates in cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {61-64},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A flock of 224 Dorset x Romney ewes was converted from September lambing in 1977 to 96\% autumn lambing (mean 16 May) in 1983 while increasing flock size by 50\%. Although various techniques of oestrous induction through teasing were used, it was considered that simply introducing entire rams at least 1 cycle before successful tupping was required, eventually gave good results. Four autumn lambing the interval between joining and the first known conception of mature ewe was 35 d during the early years, and declined to 5 d in 1983 to 1987. This decline is suggested to be a genetic change. After the capacity for out-of-season breeding had been developed in all ewes (1982 to 1987), ewes lambing in spring, when subsequently mated to lamb in autumn after a 7 month lambing interval, showed only an 8\% disadvantage in conception over those mated to lamb in the following spring after a 12 month lambing interval. Changes in the flock were brought about by culling of spring-lambing ewes and selection of replacements primarily from early lambers. From 1980, rams born to early lambing ewes were used and their first offspring lambed in 1982. This appears to have had a marked effect on 2-tooth lambing times.},
	issn = {1176-5283},
	author = {Visser A and Shannon P and Wickham BW}
}
@conference {39999,
	title = {Effects of milkfat yield and conformation traits on retention for a second lactation of Friesian and Jersey-sired cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {83-86},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Data from mature ewes repeatedly re-immunised against androstenedione or oestrone in 3 trials at the Ruakura (Coopworths), Wairakei (Perendales) and Whatawhata (Romneys, Coo9pworths and Perendales) Animal Research Stations, were analysed to estimate the repeatability of ovulation rate and number of lambs born per ewe. Immunisation responses were within the range of those reported previously (Smith, 1985). Between-year repeatability estimates were on average similar for immunised and non-immunised ewes. The unweighted average of the estimate was 0.29 for ovulation rate and 0.009 for number of lambs born, consistent with published values. The results suggest that the joint contribution of genetic and permanent environmental sources of variation to phenotypic differences between animals is similar under both physiological states. The high repeatability of ovulation rate in comparison with number of lambs born supports other published indications of its possible value for improvement of reproductive rate through selection.},
	issn = {1176-5283},
	author = {Ahlborn-Breier G and Wickham BW}
}
@conference {39998,
	title = {Prediction of changes in somatic cell counts due to culling and selection},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {77-82},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Genetic variation of foot and jaw {\textquoteright}abnormalities{\textquoteright} in ewe hoggets and ewes has been studied with several breeds and strains at the Rotomahana Research Station. Foot and digit placement, foot roll, pastern angle and degree of hoof growth were scored for all 4 feet of each sheep at 9 months, 18 months and 5 years of age. Teeth occlusion, measured as the distance in mm (+ or -) between the front surface of the central incisors and the anterior edge of the upper pad, was recorded at 18 months and 5 years of age. Differences in incidence of foot abnormalities at 18 months of age among 2251 ewe hoggets representing 6 Romney strains and Coopworth or Border Leicester x Romney crosses, were significant for all traits except foot roll and digit placement. Border Leicester cross hoggets had a lower incidence of foot placement, pastern angle and hoof growth abnormalities than straightbred Romneys or Coopworth crosses. In a separate trial, 602 Booroola Merino first cross hoggets out of Romney and Perendale ewes had a significantly higher incidence of foot abnormalities than 480 straightbred Romney or Perendale ewe hoggets for all traits recorded at 18 months of age except pastern angle. There were only small differences among Romney strains and among breeds and crosses for teeth occlusion. Paternal half sib heritability estimates of foot traits recorded at 9 months of age were low (less than 0.11) and non-significant except for hoof growth (0.18 to 0.29). Similar heritability estimates for hoof growth were found in 189 month ewe hoggets (0.14 to 0.27) with low to moderate estimates for the other foot traits (0.02 to 0.17), and teeth occlusion (0.13 to 0.25). Heritability estimates were similar in 5- year-old-ewes for foot traits (0.03 to 0.20) but increased with age for teeth occlusion (0.36). Correlations between foot traits recorded at 18 months and 5 years of age were low (0.08 to 0.25), but were higher for teeth occlusion (0.49). Foot abnormalities and teeth occlusion were not found to have significant effects on either hogget growth, wool production or ewe reproduction, live weight or wool production. It is concluded that undue culling emphasis in ewes or rams on teeth or feet abnormalities is not warranted and may be counter productive.},
	issn = {1176-5283},
	author = {Smit H and Wickham BW}
}
@conference {39889,
	title = {The research potential of shared information resources},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {44},
	year = {1984},
	month = {Jan},
	pages = {83-86},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Genetic engineering of micro-organisms to produce mammalian protein hormones promises to make the hormonal treatment of ruminants for the stimulation of lactation, growth and wool growth commercially viable. Treatment of lactating dairy cows with growth hormone (GH) commonly elevates milk production by about 4 kg milk/d. In growing beef and sheep GH increases nitrogen retention, reduces carcass fat content and may increase growth rate. Wool growth increases following the cessation of GH treatment. Many of the actions of growth hormone are likely mediated by a {\textquoteright}family{\textquoteright} of hormones, notably insulin-like growth factors I and II and epidermal growth factor. The efficacy of these materials in promoting production has not been investigated. Sustained-release implants have been developed which will deliver protein hormones over prolonged periods. However, the ability to promote production by direct manipulation of the animal genome may be the most economic approach. For example, injection of rat GH genes into fertilised mouse eggs resulted in mice that grew 2 to 4 times faster than normal.},
	issn = {1176-5283},
	author = {Wickham BW}
}
@conference {39636,
	title = {Genetic parameters and economic values of traits other than production for dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {39},
	year = {1979},
	month = {Jan},
	pages = {180-193},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Wickham BW}
}
@conference {39547,
	title = {The relationship between Central Test Station performance and subsequent progeny performance for growth traits of Hereford Bulls},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {37},
	year = {1977},
	month = {Jan},
	pages = {89-95},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Wickham BW}
}
