@conference {41032,
	title = {Calpain and tenderness comparisons in M. longissimus dorsi samples from weight-selected and control Angus cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {214-217},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Meat samples (M. longissimus dorsi) from a control Angus herd (ACO) and associated selection herd (AS1) were compared for calpain/calpastatin concentrations and shear-force tenderness, after the herds had been subjected to 22 to 24 years of random replacement or selection for increased adjusted yearling weight. The objective was to monitor changes in meat tenderness at fixed slaughter date resulting from genetic selection, and associated changes in muscle calpain or calpastatin concentrations. Bull calves (n=94), from 3 successive calf crops raised on pasture, were slaughtered immediately after arrival at the abattoir at about 20 months of age on one day each year (May 1995, 1996 and 1997). Carcasses were electrically stimulated, weighed and hot boned. Meat samples for calpain/calpastatin analysis were taken within 30 minutes of slaughter from the M. longissimus dorsi, with further samples after 24 hr of ageing at 10{\textdegree}C. Shear-force tenderness was assessed on the same muscle at intervals from 24 hr until one month of ageing at -1{\textdegree}C. Calpastatin, milli- and micro-calpain activities were assayed using casein as a substrate. Yearling live weights, hot carcass weights and muscle weights were respectively 19.0\%, 16.5\% and 17.3\% greater in the AS1 than the ACO herd (all P<0.001). The AS1 samples were on average 8 to 16\% more tender than ACO samples (P<0.05) on days 1 and 3 post mortem, but there were no significant herd differences in tenderness at later ageing times. The between-animal repeatability of shear-force tenderness from days 1 to 28 was 0.44{\textpm}0.07. Millicalpain concentrations were significantly lower in the AS1 than ACO samples by an average of 13\% (P<0.001), and there were smaller differences in microcalpain and calpastatin between herds in the same direction. These results show that early post mortem tenderness, millicalpain and possibly microcalpain and calpastatin concentrations were associated with genetic differences in growth. },
	issn = {1176-5283},
	author = {Morris CA and Speck PA and Cullen NG and Dobbie PM}
}
@conference {40814,
	title = {The calpain proteolytic system in different types of ovine skeletal muscles and relationship to meat tenderness},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {198-200},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The calpain system is involved in postmortem tenderisation of meat.  Muscle type also influences tenderness and aging rate. This study  investigated the extent to which differences in the calpain system may  account for differences in tenderness. Calpain and calpastatin activities were  measured from 12 different ovine muscles. Shear force was determined on  muscle aged at 15 C for 1, 2, 3 and 4 days postmortem and ultimate pH  measured. Calpastatin, },
	issn = {1176-5283},
	author = {Singh K and Dobbie PM and Simmons NJ and Bass JJ and Thomson BC and Speck PA}
}
@conference {40813,
	title = {Differences in the post mortem kinetics of the calpain system in meat from bulls and steers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {195-197},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This experiment investigated differences in meat tenderness as defined  by shear force between bulls and steers, and how these related to differences  in the post mortem kinetics of the components of the calpain system. Strip  loins (m. longissimus dorsi) from bulls with acceptable (pH < 5.7) ultimate  pHs were compared with strip loins from prime steers. Samples were aged  for 1, 3, 7, 13, 24, 48 and 72 hours at 15 C. The activities of calpastatin and  (},
	issn = {1176-5283},
	author = {Thomson BC and Dobbie PM and Simmons NJ and Singh K and Speck PA}
}
@conference {40805,
	title = {Genetic improvement of meat quality in sheep and cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {157-162},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Genetic variations in body composition are apparent as differences  among breeds, crosses, selected strains and sire groups. Crossbreeding, use  of terminal sires and selection within breeds has tended to concentrate on  total meat output rather than quality, despite consistent consumer signals  against fat. Evidence suggests that, in males selected using live animal  ultrasound measurements of fat and muscle depths, about half of the  selection pressure available to improve growth rate should be sacrificed in  order to maximise economic response through decrease in carcass fat  content. Genetic variations in lean/fat partitioning to different regions and muscles of  the carcass, and in traits affecting the wider sensory appeal of cooked meat,  are also important to the range and consistency of meat products. Indirect  live animal indicators are vital to minimising the high cost of progeny  testing. Meat product tenderness is one example. Much of the variation is  under the control of the calpain system for which genetic differences have  been found among breeds and crosses, related families, selection lines, and  in strains segregating for major genes and genetic markers (e.g. calpastatin  and the CSSM18 and TGLA122 markers of the callipyge gene in sheep).  Decreased post mortem tenderness is associated with decreased proteolytic  enzyme activity which in some cases is related to increased lean growth  rates in the live animals as well. Between and within muscle variations in actin/myosin interactions, lipid,  myoglobin contents and solubilities can also give rise to genetic variations  in tenderness, meat flavour, colour and the heat gellation properties of  myosin. The biochemical basis of these effects suggests useful indicator  traits (e.g. LDH and ICDH enzyme activity associations with fibre type,  intra-muscular fat and haem iron contents) which are likely to offer  innovative genetic solutions to long-term industry competitiveness.},
	issn = {1176-5283},
	author = {Clarke JN and Morris CA and Speck PA and Upreti GC and Nicoll GB}
}
@conference {40810,
	title = {Postmortem changes in pH and shear force in three commercial bull beef cuts},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {184-186},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This experiment investigated the differences between fillet, strip loin  and rump cuts obtained from carcasses of pasture-fed bulls. Four samples of  each cut were collected on two different occasions and aged at 15 C for 2,  24, 48 ,72 and 120 hours. The pH of the fillet and rump cuts did not change  post-slaughter. The pH of the strip loin was higher at slaughter but declined  over time and by 48 hrs post-slaughter there were no differences in the pH  value of the three cuts. Shear force was determined using a MIRINZ  tenderometer. The fillet had the lowest shear force and the rump cut had the  highest. There were no differences in the activities of the components of the  calpain system at 2 hours post-slaughter. These results suggest that the  differences in meat quality and particularly ultimate tenderness, between the  three cuts were not due to differences in the activities of the components of  the calpain system or pH },
	issn = {1176-5283},
	author = {Thomson BC and Dobbie PM and Singh K and Speck PA}
}
@conference {40801,
	title = {Quality Meats From The NZ Beef And Sheep Industries - Consistent quality meat products},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {146},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Meat quality has different definitions for different people and in different countries, depending on their posi-tion in the value chain. However, the consumer who repre-sents the endpoint of the chain has clearly signaled inconsistent quality of meat as a major consideration in the declining purchases of red meat.},
	issn = {1176-5283},
	author = {Speck PA and Kirton AH and Clarke JN}
}
@conference {40688,
	title = {The Calpain System - genotype, nutrition and their interactions},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {123},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Three groups of pregnant (3rd trimester) cows grazing low Se pastures  were given daily Se intakes of 0.44, 0.94 and 1.44mg respectively as pasture  plus a drench. A significant relationship between blood Se concentration  (nmol/l) [y] and daily Se intakes (mg/day) [x] was described by the equation  Y=147(44.0+(359(42.1)X***. Given that a mean blood Se concentration of  250 nmol/l reflects an adequate Se status, that is there is no production  response to Se supplementation, then the daily Se intake of pregnant cows  was determined to be 0.29mg or pasture should contain 0.037mg Se/kg DM  to prevent Se deficiency.  },
	issn = {1176-5283},
	author = {Speck PA and Singh KK and Thomson BC and Dobbie PM and Mercer GK and Bass JJ and Simmons N and Binnie B and Clarke N}
}
@conference {40687,
	title = {Inter-muscle variation in the calpain system of red deer:- implications for meat tenderness},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {120-123},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A grazing trial using 24 Red and 24 Hybrid (0.75 Red; 0.25 Elk) deer  weaners was conducted from 1st March to 12th December 1993, to compare  the feeding value of chicory (Cichorium intybus L) with that of  perennial ryegrass (Lollium perenne)/white clover (Trifolium  repens) pasture for increasing venison production by one year of age.   The deer were rotationally grazed using dry matter allowances of 6, 6 and 7  kg DM/head/day in autumn, winter and spring respectively. Relative to deer  grazing pasture, deer grazing chicory had higher voluntary feed intake (VFI),  slightly lower grazing (ie. eating) time and substantially lower ruminating  time. Hybrid deer had faster liveweight gain (LWG) than Red deer and were  heavier at the end of all seasons (P<0.01). LWG was greater on chicory than  on perennial ryegrass/white clover pasture during autumn (P<0.01) and there  were forage x genotype interactions for liveweight at the end of autumn and  spring, with Hybrid deer (especially stags) being heavier when grazed on  chicory. Carcass weight for Red and Hybrid stags was 64.9 and 73.0 kg  when grazed on chicory and 56.6 and 57.0 kg when grazed on perennial  ryegrass/white clover pasture. Grazing chicory advanced the date of first cut  velvet antler by 28 days and increased the weight of total (first cut+regrowth)  velvet antler. It is concluded that grazing chicory increased venison  production, especially in Hybrid stags with increased growth potential, and  increased velvet antler production.  },
	issn = {1176-5283},
	author = {Dobbie PM and Singh KK and Thomson BC and Mercer GK and Bass JJ and Speck PA}
}
