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Item Venison and velvet production from Red and hybrid deer by one year of age : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University, New Zealand(Massey University, 1996) Min, Byeng-RyelA grazing experiment was conducted at Massey University Deer Research Unit, Palmerston North, New Zealand during 1995, to study the effects of grazing chicory (Cichorium intybus), Lotus comiculatus and perennial ryegrass (Lolium perenne)lwhite clover (Trifolium repens) pasture upon the growth, voluntary feed intake (VFI), venison and velvet production of red and hybrid (0.75 red;0.25 elk) deer from weaning to slaughter at one year of age. The animals were randomly allocated to graze either chicory, lotus or pasture and grazed these forages during autumn and spring using a rotational grazing system, with each group balanced for genotype and sex. All groups were joined to graze pasture during winter, when chicory and lotus were dormant. 1. Few animals attained the target slaughter weight (50kg carcass or greater) when grazing pasture and spiker velvet antler weight was low at approximately 0.2 kg per stag. 2. In this study the greatest advantages obtained for specialist forages were for chicory. Carcass weight of deer grazing chicory was higher than for deer grazing pasture, due mainly to increasing autumn LWG and dressing-out percentage at slaughter, with a smaller response in spring LWG. The largest carcass weights were consistently obtained from hybrid stags grazing on chicory, with values for red deer and hybrid stags being 56.0 and 59.3 kg when grazed on chicory and 48.6 and 53.3 kg respectively when grazed on pasture. Chicory had a higher organic matter digestibility (OMO) and VFI than pasture during autumn but similar values in spring, accounting for its autumn growth stimulation. Carcass subcutaneous fat depth (GR) was higher for deer grazing chicory than pasture, but after being adjusted to equal carcass weight, there was no difference in GR measurement. Relative to deer grazing on pasture, grazing on chicory increased total spiker velvet antler production (323 v 225 g/stag), by advancing the dates of pedicle initiation (18 days), velvet antler initiation (24 days), and first velvet cutting (17 days) and increasing the rate of velvet antler length growth. Initiation of velvet growth was correlated with liveweight, with each 10 kg increase in liveweight advancing the dates of pedicle initiation, commencement of velvet growth and first velvet cutting by 10, 18 and 13 days respectively. Correction of the data to equal liveweight removed a component of the advancement produced from feeding on chicory, but an effect still remained due to chicory feeding per se. It was concluded that grazing chicory not only increased carcass weight (especially in hybrid stags), but also increased velvet antler production. This was achieved by increased VFI and increased OMO of chicory in autumn, relative to deer grazing pasture, and probably by increased absorption of protein and minerals in deer fed chicory. 3. OMO of lotus was higher than that of pasture during autumn, but not in spring. The OMO of either chicory or lotus showed little change between seasons, but pasture changed with the season, being of lowest OMO in autumn and highest OMO in spring. 4. Responses to deer grazing lotus were limited by the reduced number of grazing days that could be achieved, due to problems in lotus establishment. In spite of these problems, grazing lotus (48 gCT/kg OM) did increase the LWG of stags during autumn (248 v 176 g/day) and increased the efficiency of growth in spring, with LWG being similar to deer grazing pasture, but VFI being lower (1.53 v 2.00 kgOM/day) for lotus compared to pasture. Although deer grazing lotus had a similar carcass weight compared to deer grazing pasture, dressing-out percentages of deer grazing lotus were higher than that of deer grazing pasture (56.4 v 53.2 %). The carcass GR tissue depth of deer grazing lotus had similar values compared to pasture. There was no interaction between forage and genotype for carcass weight and dressing out percentage. Stags grazing lotus did not show any advancement in dates of pedicle initiation, velvet antler initiation and weight of velvet production compared to stags grazing pasture. 5. Total condensed tannin (CT) concentration in lotus was 48 and 13 g/kgOM in hand plucked and oesophageal fistulae (OF) extrusa samples respectively. Most CT in hand plucked lotus samples was extractable, with much smaller amounts being protein-bound or fibre-bound. Extractable CT was not detected in lotus OF extrusa samples, and the concentration of protein-bound and fibre-bound CT remained similar to hand plucked samples. Therefore, after chewing during eating, the extractable component of CT in lotus feed could not be extracted and detected by the Butanol/HCI analysis methods and may have been bound to deer salivary proteins. Total CT in both hand plucked and OF extrusa samples was 3.1 v 5.8 g/kgOM for chicory and 0.3 v 1.5 g/kgOM for pasture. As a result, chewing (in OF samples) did not reduce the CT content of pasture or chicory. This may be due to the low concentration of extractable CT (and high proportions of bound CT) in these forages, which may have limited access for the deer salivary CT-binding proteins. 6. Overall it was concluded that chicory was of very high feeding value (FV) and had excellent nutritional advantages for increasing deer production. However, crops of chicory need to have specialised grazing management to increase persistency. New chicory cultivars need to be selected to increase persistency and to reduce reproductive stem formation during summer. Effects of protein supply on initiation of pedicle and velvet antler development in weaner stags grazing fresh forages also needs to be studied. The small responses obtained in the present study give some indication that the CT content of Lotus comiculatus may have a number of values for improving the efficiency of growth in young deer. Further experiments are needed in this area.Item The effect of sire on growth and meat production of beef-cross-dairy cattle in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Manawatū, New Zealand(Massey University, 2021) Martín, Natalia de la PazBeef-cross-dairy cattle are the progeny produced by mating dairy-breed cows with beef-breed sires. Little is known about the performance of beef-breed sires for growth, carcass and meat quality traits when used to generate beef-cross-dairy cattle in pasture-based systems. Yet, beef-cross-dairy cattle make up around 30% of the finishing cattle in New Zealand, and so improving their performance would enhance the efficiency and productivity of the beef industry. The general aim of this study was to investigate the effect of sire on growth and meat production of beef-cross-dairy cattle in New Zealand. The specific objectives were: to evaluate live weight from 4 months of age until slaughter, carcass and meat quality traits of a selection of Angus and Hereford sires via progeny testing of beef-cross-dairy offspring grown on hill country pasture; to quantify the relationship between the performance of the beef-cross-dairy progeny and sires’ estimated breeding values (EBV) for growth and carcass traits; and to assess skeletal size and temperament measured within the first 200 days of life as predictors of carcass and meat quality traits for beef-cross-dairy cattle. Data from 1101 beef-cross-dairy calves born to 2-year-old or mixed-aged dairy-breed cows were used to analyse live weight, carcass and meat quality traits of 73 beef-breed sires (34 Angus and 39 Hereford). Meat samples were obtained for analysis in the laboratory from 326 progeny of 33 sires used via artificial breeding (AB) on mixed-aged dairy-breed cows. Progeny group means for live weight, carcass weight, eye muscle area (EMA), rib fat depth, marbling scores and intramuscular fat (IMF) of 29 Angus and 34 Hereford AB sires, were regressed against sire EBV within breed. Finally, 486 beef-cross-dairy calves had measurements of skeletal size and temperament evaluated as predictors of carcass and meat traits. The mean of the progeny group means for live weight was 118.6 kg at 131d, and increased to 503.6 kg at 800d. Mean of the progeny group means was 277.3 kg for carcass weight, 240.3 cm for carcass length, 73.6 cm2 for eye muscle area (EMA), 7.4 mm for rib fat depth, 0.91 for marble score, 3.05 for fat colour score and 3.01 for meat colour score. Sire affected (P<0.05) live weight of the progeny at all ages and all carcass traits, but few meat quality traits (fat yellowness b*, meat redness a* and yellowness b*, cook loss and shear force). Differences in live weight between the lightest and heaviest progeny group means increased from 19 kg at 131d to 90 kg at 800d, and there was a 46 kg difference in carcass weight between the heaviest and lightest sire tested. The coefficient of variation (CV) among sires for EMA was 5% and for measured rib fat depth was 19%, with no sire mean below 3 mm and most progeny (97%) grading “P” fat class. For marble scores, there was 35% CV between sires even though all progeny had low marble scores between 0 and 3. There were small sire effects for carcass length, cook loss and shear force (P<0.05). Meat and fat colour scores were not affected by sire, and although there were small sire differences in fat yellowness b*, no progeny carcasses were classified as being too yellow. Live weight of the progeny groups increased with sire EBV for live weight at 400, 600 and 800 days of age (between 0.24-0.43 kg increase in progeny live weight per extra kilogram of sire EBV), although sire EBV had no effect on the live weight of the progeny at 200 days of age (P>0.05). For the Hereford sires in this experiment, progeny carcass weight increased 0.27 kg and EMA 0.70 cm2 per extra 1 unit in sire EBV for each trait (P<0.05). For the Angus sires, progeny rib fat depth increased 6.9 mm, marble score 0.91 and estimated IMF 2.26% per extra 1 unit in sire EBV for each trait (P<0.05). Live weight at birth, 129d and 200d predicted future carcass size (P<0.05). In heifers, the accuracy of predictions of carcass weight from live weight were low to moderate (R2= 17 to 31%) and increased if live weight was combined with hip-height. In steers, live weight alone could predict carcass weight with moderate accuracy (R2= 39 to 48%). Accuracy of prediction for carcass weight of steers increased with age, or with combining live weight with body length at 0d, or with hip-width at 129d. Thicker cannon bones at birth also gave an indication of heavier carcasses for both heifers and steers. Cattle in this study were calm at 200d (mean exit velocity of 1.2 m/s and crush score of 1.4) and temperament did not influence production traits in this study. The data presented in this study indicated that using genetically superior beef-breed sires over dairy-breed cows increased the growth, carcass and meat production of their beef-cross-dairy progeny. Dairy farmers should consider BREEDPLAN EBV when selecting beef-breed sires to mate their dairy-breed cows, not only for positive calving outcomes but for achieving desirable and economically important carcass and meat quality traits. The beef cattle finisher should consider the calves’ potential for growth and fattening when purchasing beef-cross-dairy calves for beef production, by utilising both genetic and phenotypic live weight information.Item Viability of dairy-origin calves for a new beef production enterprise in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Agricultural Science at Massey University, Palmerston North, New Zealand(Massey University, 2019) Hunt, Joshua JamesThe New Zealand dairy industry produces approximately 4.2 million calves annually, of which about 30% are retained within the dairy industry, while a further 20% are utilised in the beef industry. The remainder are surplus to requirements, and the majority (1.7 million per annum) are processed in the low value bobby calf trade. This model appears sub-optimal, with an estimated opportunity cost in excess of NZD $1 billion annually, and numerous animal welfare and ethical issues. Farming surplus dairy calves in an accelerated-cycle beef production enterprise for slaughter prior to one-year of age, could generate favourable outcomes, and the current study aimed to investigate this opportunity. Experimental growth and carcass data for Hereford x Friesian-Jersey steers slaughtered at 8-, 10- and 12- months of age was obtained in a live-animal trial. Simulation models (referred to as NGB8, NGB10 and NGB12 where the figures refer to monthly ages at slaughter) utilising Microsoft EXCEL feed budgets, gross margin analysis and the OVERSEER nutrient budget model were developed from the experimental data to estimate the physical, financial, and environmental performance of accelerated-cycle beef production at each slaughter age. Results were compared to a simulated high and low performing bull- beef enterprise based on the literature, with slaughter occurring at 18- or 24-months, to determine the relative performance of accelerated-cycle beef production. The model comparators are referred to as Bull18 and Bull24. In the trial, the accelerated-cycle beef production (NGB) steers achieved slaughter weights of 252, 303 and 348 kg at 8-, 10- and 12-months of age (119, 146 and 174 kg carcass weight). The dressing out percentage was the same in the 8- and 10-month treatments (P>0.05) but increased in the 12-month treatment (P<0.001). Using the ‘prime’ beef price, NGB8 and NGB10 generated a loss, while NGB12 was profitable. To be financially competitive with Bull18 or Bull24, NGB production required a price premium of 11 – 29% above the ‘prime’ beef schedule. There was insufficient evidence to suggest NGB production had a lower nutrient loss footprint, or reduced greenhouse gas output compared to bull-beef production. Further analysis showed weaner genetic merit for growth had a positive relationship with profitability, but no interaction with environmental output under NGB production. Overall, this study demonstrated that Hereford x Friesian-Jersey steers can grow well under typical beef finishing conditions. Given that accelerated-cycle beef production’s environmental output is similar to bull-beef production, profitability is the key determinant of the concept’s viability. Although NGB production with slaughter occurring at 12-months of age was profitable under the ‘prime’ beef classification, a premium of 11 – 29% (depending on slaughter age) would be required for the proposed enterprise to be financially competitive with bull-beef production. However, research has shown the meat derived from this production system is of high quality, therefore there is potential for a price premium if suitable markets are located. Finally, the procurement of weaners with high genetic merit for growth represents an opportunity to further enhance the proposed enterprises overall performance.Item Investigating the relationship between lamb weaning age and forage diet on carcass and meat quality : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science, Massey University, Palmerston North, New Zealand(Massey University, 2019) Kok, Jacobus ChristiaanLamb carcass characteristics and meat quality are important components of the value chain that determine the carcass value and price obtained. On-farm factors can affect carcass characteristics and meat quality of lamb, however, the effect of early weaning and forage diet on carcass and meat quality characteristics is not well-known. Therefore, this thesis considers the relationship between weaning age and the forage diet for influencing carcass characteristics and meat quality of lamb. The study compared carcass characteristics and meat quality of early weaned lambs (at eight weeks of age) grazing a plantain-clover mix, and conventionally weaned lambs (at 14 weeks of age) grazing a plantain-clover mix or perennial ryegrass-white clover pasture with all lambs finished for six weeks as one mob on perennial ryegrass-white clover pasture to achieve a target minimum live weight of 35 kg at slaughter (Chapter 3). Forty-three Romney ewes rearing twin lambs (86 lambs) were used in this study. Ewes and their lambs were allocated to one of four treatments: 1) lambs weaned early (eight weeks of age) on a plantain-clover mix (EARLY), 2) lambs with dam grazing a plantain-clover mix (HERB), 3) lambs with dam grazing perennial ryegrass-white clover pasture >1200 kgDM/ha (HIGH), and 4) lambs with dam grazing perennial ryegrass-white clover pasture <1200 kgDM/ha (LOW). Lambs in treatments 2, 3, and 4 were weaned at 14 weeks of age. Lambs in the HERB treatment had the fastest growth rate, yielding heavier carcasses and a higher dressing out percentage compared to EARLY and LOW lambs. HIGH lambs had intermediate growth rates, carcass weights and dressing out % (Chapter 5, Table 8). Physical dissection of the hind leg showed lambs in the EARLY treatment had the least dissectible fat compared to HIGH and LOW lambs which had the most, with HERB lambs intermediate. In addition, lambs in the EARLY treatment had a similar fat% and muscle% compared to HERB and LOW lambs but produced lower fat% and higher muscle % than lambs in the HIGH treatment (Chapter 5, Table 9). Objective measurements of lamb meat quality only showed a difference among treatments for sarcomere length and total shear force work (Chapter 5, Table 10). Lambs in the EARLY and HIGH treatments had the longest sarcomere lengths and lambs in the HERB treatment the shortest, with intermediate lengths recorded for LOW lambs. Meat from lambs in the EARLY, HERB and LOW treatments required less total shear force work than lambs in the HIGH treatment. Although statistically significant the relative difference in results was not substantial, indicating that generally the treatments had no effect on meat quality. Early weaning of lambs onto a plantain-clover mix does not have negative effects on carcass and meat quality. However, the slower growth rate of early weaned and restricted perennial ryegrass pasture raised lambs resulted in lower carcass weights in this study indicating that a lower nutritive diet as a consequence of using grass species or a lack of milk intake will mean lambs will need more time to achieve a set finishing weight.Item Carcass characteristics and meat quality of dairy-origin steers slaughtered at eight, ten and twelve months of age : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Agricultural Science, Massey University, Palmerston North, New Zealand(Massey University, 2019) Pike, Samuel JohnApproximately 2 million surplus calves are produced annually by the New Zealand dairy industry, which are generally processed at around one week of age as “bobby” calves. Concerns surrounding animal welfare issues, due to the ethics of slaughtering calves at such a young age, pose a threat to the industry’s social licence to farm, consumer acceptability and market access. In addition, the beef sector also faces the challenge of improving production efficiency, whilst minimising environmental impacts. To address these issues, a novel yearling beef production system is proposed, that would utilise dairy-origin calves and implement a slaughter age of between eight and twelve months. The objective of this study was to compare carcass characteristics and meat quality attributes of Hereford x Friesian-Jersey steers slaughtered at eight, ten and twelve months of age, in order to understand the potential saleable meat yields and type of meat product that could be sourced from yearling dairy-origin cattle. Additionally, the study aimed to determine if postmortem ageing had an effect on meat quality attributes. Sixty Hereford x Friesian-Jersey weaner steer calves born in spring 2017 were sourced from a commercial calf rearer at three months of age (average 103±1 kg live weight). The calves were managed as a single group; however, they were randomly pre-assigned at eight months of age to one of three slaughter treatments: eight, ten and twelve months of age. Steers were grazed on herb-clover pastures and brassica crops from December 2017 to March 2018, then on ryegrass and white clover pasture until slaughter. Steers were processed in May, July and September 2018 at eight, ten and twelve months of age respectively, at Venison Packers Feilding Ltd. Growth rates of the three slaughter groups averaged 0.9 kg/day and did not differ between treatments. The final unfasted live weights prior to slaughter at eight, ten and twelve months of age were 252±6 kg, 303±4 kg and 348±5 kg respectively (P<0.001), which corresponded to carcass weights of 119±3 kg, 146±3 kg and 174±3 kg (P<0.001). Steers slaughtered at twelve months of age achieved a greater dressing-out percentage (50.0±0.2%) than steers slaughtered at eight (47.2±0.2%) and ten (47.4±0.2%) months of age (P<0.001). Rib fat depth, P8 fat depth and eye muscle area measured by ultrasound increased at each age (P<0.001). Fat depths at all three ages were below 3 mm, which is the minimum fat depth required for steers to be classified in the ‘P’ fat class designating 3-10 mm of subcutaneous fat, under the current beef carcass classification system. The muscle to bone ratio, intramuscular fat content and yellowness of carcass fat all increased progressively with slaughter age. Objective meat quality attributes were measured on the M. longissimus lumborum (striploin). The caudal half of each striploin muscle was aged for 21 days in vacuum packaging, while the cranial half was frozen immediately after boning, 24 hours postmortem. Shear force values for unaged samples at eight, ten and twelve months of age were 5.1±0.2 kgF, 5.4±0.2 kgF and 5.5±0.2 kgF respectively. Although there was no difference in shear force values, sarcomere length or drip loss between the three slaughter age treatments (P>0.05), ultimate pH and thaw loss increased with age, while cooking loss declined. Meat colour also became darker and redder as animals became older (P<0.001). Proteolytic ageing for 21 days had a positive effect on shear force values and water-holding capacity at all slaughter ages, though differences were minimal (P<0.001). Overall, the changes in carcass characteristics with age were small, likely due to there being only four months’ difference in age between treatments. However, the greater saleable meat yields and dressing-out percentages at ten and twelve months of age may be advantageous in terms of processing efficiency and profitability. Differences in objective meat quality measures between eight, ten and twelve months of age were also small, indicating that the yearling beef is very tender and of high eating quality. This suggests that the beef obtained from beef-dairy cross cattle slaughtered between eight and twelve months of age and at live weights of 250-300 kg could be processed together under one category, and that the product could justifiably be targeted at markets which offer a premium.Item Some aspects of the bone-muscle relationships in New Zealand lamb and mutton carcasses : a thesis presented at Massey Agricultural College in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand(Massey University, 1961) Russel, A. J. F.The three main constituents of a meat carcass are bone, musele, and fat, and of these the lean meat or muscle is of greatest interest and importance to the consumer. Bone represents an almost total waste and is hence considered as undesizable and as something which must be accepted with the desirable muscular tissue. In the words of Robert Bakewell, "You can't eat bone, therefore give the public something to eat." (Dawson, 1957). The Physical properties of muscle and bone are markedly different. Muscular tissue is compressible and hence difficult to ensure with accuracy on a linear scale. The intimate association of skeletal muscle with other tissues makes its complete removal for accurate weight estimation both difficult and tedious. Bony tissue, on the other hand, lends itself more readily to the measurement of linear dimensions and weight.Item Growth, carcass characteristics and meat quality of heifers and steers born to beef-cross-dairy cows : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Palmerston North, New Zealand(Massey University, 2016) Coleman, Lucy WesleyIn New Zealand, there is an increasing influence of dairy breeds in the production of beef. First-cross beef-cross-dairy cows have shown potential as beef breeding cows due to their greater milk yield than straight-bred beef cows. There have been few studies examining the finishing characteristics of the progeny of such cows. The objectives of this study were to investigate the effect of breed-cross on growth, carcass characteristics and meat quality attributes for progeny of beef and beef-cross-dairy cows grown in a New Zealand pastoral production system. This study also aimed to determine if there were differences in breed effects between heifers and steers. Growth, carcass characteristics and the meat quality were assessed for steers and heifers from beef and beef-cross-dairy cows. Heifers (n=53) and steers (n=50) were born to Angus (AA), Angus-cross-Friesian (AF), Angus-cross-KiwiCross (AK) and Angus-cross-Jersey (AJ) cows and sired by Charolais (C) bulls. Heifers and steers were grazed on pasture until slaughter at 574 and 784 days of age respectively. Live animal measurements were considered separately for heifers and steers. Carcass characteristics and meat quality attributes were compared among breed-crosses and between heifers and steers. The C-AA heifers (226.8±4.7 kg) and steers (238.8±4.6 kg) were lighter at weaning than the beef-cross-dairy breed heifers (C-AJ = 239.9 ±4.6 kg, C-AK = 254.7±6.3 kg, C-AF = 258.9±5.7 kg) and steers (C-AJ = 256.1±4.9 kg, C-AK = 257.0±7.2 kg, C-AF = 267.0±5.7 kg) (P<0.05); however, there were no differences in the final live weight of breed-crosses (P>0.05). The C-AA (53.1±0.3 %) steers had a greater dressing-out percentage than C-AF (51.9±0.4 %) and C-AJ (51.5±0.3 %) steers (P<0.05). There were no differences in carcass weight, length, eye muscle area and fat depth C among breed-crosses (P>0.05). Steers were longer, heavier, had a greater fat depth C and greater proportion of intramuscular fat than heifers (P<0.05). Generally there was no difference in the meat quality among breed-crosses (P>0.05), except that C-AJ cattle had yellower fat than C-AA, and C-AA and C-AF cattle had redder fat than C-AK. There was no interaction of breed-cross with sex effects. Therefore, the C-AA cattle were more suited to a finishing system than C-AF, C-AK and C-AJ cattle.Item Selection for beef cattle carcass and meat quality traits : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University(Massey University, 1995) Charteris, Paul LeonardCarcasses in the Japanese beef market are rewarded for increased yield and superior meat quality traits such as marbling, fat colour, meat colour and firmness and texture of meat. Due to the relatively high cost of feedlotting New Zealand compared with North America and Australia, genetic improvement may provide a low-cost alternative for improving beef quality destined for the Japanese market. The objectives of this study were to characterise meat quality traits for a sample of New Zealand pasture-finished beef cattle and determine the potential rate of genetic gain for these traits through selection. Records on 24 146 Angus and 5 632 Hereford carcasses processed at Manawatu Beef Packers between March 1993 and August 1994 which had been evaluated for beef marbling standard (BMS), beef fat standard (BFS) and beef colour standard (BCS) were used to derive overall meat quality score. Overall meat quality score in the Japanese grading system is determined by the lowest grade from: semi-objective assessment for BMS, BFS and BCS; and subjective assessment for meat brightness, firmness and texture, fat lustre and quality. Subjective measures of meat and fat quality are not routinely recorded at this plant and therefore overall meat quality score could only account for the three recorded items. The majority of Angus and Hereford carcasses (84.0 and 82.9%) had an overall meat quality score of 1 (inferior) and no carcasses had score 5 (excellent). Improvement of one grade in BMS (or BFS) for Angus carcasses decreased the proportion of score 1 carcasses to 12.8% (or 74.7%) and improved overall meat quality score from an average of 1.17 to 1.96 (or 1.29). A change of one grade in BMS (or BFS) for Hereford carcasses decreased the proportion of score 1 carcasses to 16.1% (or 66.8%) and changed overall meat quality score from an average of 1.18 to 1.90 (or 1.35). Selection based on a well-designed progeny test would take 5 (or 9) years to improve BMS (or BFS) by one grade. Biological factors introduce a lag of at least six years from the start of test matings until there can be widespread harvest of beef cattle with improved meat quality. Selection for BMS can improve overall meat quality score more effectively and more rapidly than selection for other meat quality traits. Some Angus sires used in New Zealand are sourced from North America where sire expected progeny differences (EPD) for carcass traits are based on performance of feedlot finished progeny. Sires may rank differently based on progeny records from feedlot-finished cattle (North America) and pasture-finished progeny performance in New Zealand. The objective of this study was to determine importance of genotype by environment interaction effects when sires from a New Zealand Angus progeny test programme were evaluated based on pasture-finished and feedlot-finished progeny records. Fourteen Angus sires were evaluated for live weight, carcass and meat quality traits based on records from pasture and feedlot finished steer progeny. Estimated breeding values (EBV's) of sires were obtained using a Best Linear Unbiased Prediction (BLUP) procedure. Correlations between sire EBV's estimated from pasture and feedlot-finished progeny records ranged from -0.16 (for meat colour) to 0.50 (for subcutaneous fat depth). There were no significant (P<0.05) sire by environment interaction effects, which may have due to differences in site and method of measurement of traits and different slaughter facilities. Rank correlations between sire EBV's ranged from -0.13 (for fat colour) to 0.49 (for subcutaneous fat depth). Small negative rank correlations between sire EBV's were obtained for five of the eight traits analysed indicating sires tended to rank differently based on pasture or feedlot finished progeny records.Item A study of the relationships between growth, carcass and meat characteristics of Angus steers : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University(Massey University, 1982) Msechu, James Kundael KileghuaGrowth, defined as change in weight, may be considered the most important single characteristic of slaughter cattle. Fast-growing cattle may have better food conversion and reach slaughter early. The end-products in a beef production business, namely, carcass and meat, have properties which determine consumer acceptability. This study focussed attention on growth, carcass and meat characteristics in cattle. Literature was reviewed on factors that influence variability in these traits and relationships reported in the literature between some of the traits were summarised. Records on 117 Angus steers born in 1975 and 1976 (years 1 and 2) were analysed by the least squares method of fitting constants. Data included birth weight, calf milk consumption pre-weaning average daily gain (ADG), weaning weight, post-weaning ADG, yearling weight, 2-year weight, finish (30-month) weight, carcass weight, kidney and channel fat weight, eye muscle width, depth, and area, fat depth, fat trim percentage, intra-muscular fat percentage, sarcomere length, meat tenderness, muscle pH, and colour, lean percentage and bone percentage. Fixed-effects constants fitted to growth data were: herd, age of dam and peri-natal treatment (calving on pasture or sawdust pad). Covariance analysis was adopted with 3 covariates: dam autumn liveweight, calf birth weight, and milk consumption. Factors fitted to post-slaughter data were: maturity, slaughter lot and pre-slaughter fasting, with 3 covariates, carcass weight, pre-weaning ADG, and post-weaning ADG. Results were inconsistent between years. Therefore, few factors were conclusively judged to be important sources of variation in the traits studied. Herd influenced milk consumption (P<0.05) and pre-weaning ADG in year 1, and weaning and yearling weight (P<0.01) in year 2. Age of dam did not affect growth traits (P<0.10). Treatment was unimportant to pre-weaning growth in both years, but year 1 analyses suggested that it affected post-weaning ADG (P<0.01) and finish weight (P<0.05). This result may be attributed to chance. Regression on dam weight was non-significant for all growth traits. Calf birth weight was found to be an important factor as far as various growth traits in year 2 were concerned, namely, weaning weight (P<0.01), and milk consumption, pre-weaning ADG and yearling weight (P<0.05). Regression of weaning weight on birth weight approached significance (P<0.10), but birth weight was otherwise unimportant in year 1. Milk consumption influenced weaning weight (P<0.05) in year 1; approached significance for its effect on pre-weaning ADG and yearling weight in year 1, and weaning and 2-year weight in year 2 (P<0.10). Maturity did not affect post-slaughter characteristics other than eye muscle depth (P<0.05) in year 2. Slaughter lot was responsible for variation in eye muscle width (P<0.001) and dressing-out percentage (P<0.01) in year 1; dressing-out percentage and bone percentage (P<0.001) in year 2. Four-day pre-slaughter fasting affected few carcass or meat traits adjusted for carcass weight by covariance analysis. The results were inconsistent between years. In year 1, fasting affected dressing-out percentage (P<0.001) only, while in year 2 such effect was not apparent (P<0.10), but it was appreciable on other traits: eye muscle width and meat tenderness (P<0.05) and sarcomere length (P<0.001). Regression of various traits on carcass weight was significant: dressing out percentage, kidney and channel fat, fat depth, intramuscular fat percentage, fat trim percentage, eye muscle depth, eye muscle area, sarcomere length, and bone percentage in year 2; it was significant for dressing-out percentage and kidney and channel fat in year 1. Pre- and post-weaning ADG were less important covariates: the former was significant to eye muscle depth, dressing-out percentage, intra-muscular fat percentage and bone percentage in year 2, but non-significant in year 1. The latter approached significance in eye muscle area, dressing-out percentage, fat trim percentage and bone percentage in year 2 (P<0.10). Residual sums of squares were used to estimate phenotypic correlations between traits studied. Correlation coefficients between growth traits were positive and medium to high except those between early growth (pre-weaning ADG, and birth, and weaning weights) and post-weaning ADG, which were negligible. Pre-weaning ADG and weaning weight had a perfect correlation coefficient (r = 1.0) in both years. Estimates between growth and carcass traits varied widely; notable were those for post-weaning ADG, 2-year weight, and finish weight with carcass weight, which were high in both years (r = 0.86, 0.80; r = 0.80, 0.85; and r = 0.92, 0.92, respectively). Carcass traits were mostly positively correlated, with low to medium coefficients between them. Lean percentage had a strong negative correlation with fat trim percentage (r = -0.71), but bore little relationship with other traits. Correlation coefficients between carcass and meat traits were mostly positive, but low and inconsistent between years. Carcass weight was related to most fatness attributes of the carcass and meat. Most meat traits were positively correlated with each other with low and medium correlation coefficients.Item The effects of genes/QTL for muscle and fat on the weights of saleable carcass components in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Masterate of Science in Animal Breeding and Genetics at Massey University, Palmerston North, New Zealand(Massey University, 2005) Gibson, Olivia MarySheep farmers in New Zealand have the opportunity to increase income through selection based on genetic markers linked to Quantitative Trait Loci (QTL) and/or genes for a variety of traits. A small number of muscle-related QTL/genes have been discovered in sheep and include the Callipyge gene, myostatin gene and the LoinMAX™ QTL. All of these QTL/genes result in an increase in the proportion of lean meat that is produced by the lamb; the size of the increase is different between the QTL/genes. The LoinMAXTM QTL has the smallest effect on carcass composition and results in an increase in the weight and area of the eye muscle. The Callipyge gene shows a larger change in carcass composition than the LoinMAXTM QTL, resulting in a visiable increase in the muscles in the hind quarter of the sheep. The myostatin gene has a more general effect on the carcass of a sheep and results in an increase in the weight of all the muscles of the carcass and a decrease in the fat content of the carcass. Both the Callipyge and the myostatin gene also result in an increase in the dressing out percentage of the animal. There is limited information on the economic effects of introducing such QTL/genes into sheep populations. This study involved using a modelling approach to examine the impact of muscle and dressing out percentage QTL in a sheep flock. A model was established to simulate the growth of 1000 lambs from weaning to slaughter. Further models were used to simulate the processing of carcasses into cuts, with the value of the carcass estimated for both processors and farmers, based on the weight of the individual cuts. A base scenario established the size of cuts and carcass value for lambs, without the presence of known QTL/genes. Four experimental scenarios were examined based on the Callipyge gene, the myostatin gene, the LoinMAXTM QTL, and the effects of the Callipyge and myostatin gene on dressing out percentage. Within each scenario, the QTL effect was estimated at four different magnitudes. The model output for each of the QTL effects was compared to the base model to estimate the additional income of the meat processor when purchasing lambs from farmers who had used the QTL/gene and also the additional income to the farmers. This study found that the use of muscle QTL/genes in a New Zealand flock has variable effects on the income generated for the processor and the farmer. All the QTL/genes in the study, which were loosely based on muscle QTL/genes currently identified in sheep, resulted in an increase in income for both farmers and processors. The scenario that was based on the LoinMAXTM QTL generated an additional $0.80 to $1.80 per lamb for the processor and an additional $0.56 to $1.26 per lamb for the farmer. The effect of the Callipyge gene resulted in an increase in the income generated for the processor of between $12.59 and $14.97 per lamb, and between $8.81 and $10.48 per lamb for the farmer. The last of the muscle QTL/genes analysed was the myostatin gene, the use of this gene in a commercial flock resulted in between $4.19 and $7.99 per lamb additional income for the processor and between $2.93 and $5.59 per lamb for the processor. When the effect of a dressing out percentage QTL was run through the model the additional income generated for the processor, when the QTL effect was between 5% and 10%, was within $3.56 and $8.ll and the additional income for farmers was between $2.49 and $5.68. It can be concluded from this study that the size of the QTL/gene effect and the muscles that are affected by the QTL/gene will influence the additional income that can be generated for the farmer and the processor. In general additional income can be achieved; however, whether or not this outweighs any additional costs that may be associated with using such QTL/genes needs further investigation.