@article {3672, title = {Impact of winter near-maintenance or non-restricted feeding on growth and intramuscular fat content of yearling rams}, journal = {New Zealand Journal of Animal Science and Production}, volume = {81}, year = {2021}, month = {01/2022}, pages = {141-145}, address = {Online}, abstract = {There is increased interest in genetic improvement in intramuscular fat in lamb due to its positive association with meat quality. Live-animal measures such as ultrasound or computed tomography scanning can enable genetic selection. The optimum time at which such measurements should take place is unknown. This study investigated levels of intramuscular fat in year-old rams. During the winter of 2020, ram lambs were fed on either a just-above-maintenance pasture diet (JAM) (n=119) with a target weight gain of 50 g/day, or non-restricted feeding (GAIN) (n=120) with a target weight gain of 180-200 g/day, with all rams slaughtered after 10 weeks of differential feeding. Both groups of rams were fed a ryegrass-dominant pasture. The target for the GAIN group was achieved with an average growth rate of 182{\textpm}42 g/day (range 76 to 293 g/day), however, for JAM group the average growth rate was 24{\textpm}64 g/day (range -212 to 126 g/day), with a third of the animals losing weight. The JAM group were split according to whether they had gained (JAM {\textendash} Gain) or lost weight (JAM {\textendash} Loss) for the analysis. There were differences (P<0.001) at the time of slaughter in early spring in carcass weight between groups (23.7{\textpm}0.35, 19.5{\textpm}0.40 and 17.0{\textpm}0.47 kg for GAIN, JAM {\textendash} Gain and JAM {\textendash} Loss respectively). The levels of intramuscular fat were low across all groups compared to levels normally observed in 6-8-month old ram lambs and with further differences (P<0.001) between the three groups (2.1{\textpm}0.08, 1.9{\textpm}0.09 and 1.4{\textpm}0.10 kg for GAIN, JAM {\textendash} Gain and JAM {\textendash} Loss respectively). More work is required to understand management systems that allow improved expression of the trait. Additionally, careful consideration needs to be given to winter grazing management of all young stock, as there is considerable variability in individual animals handling of winter maintenance feeding. Keywords: lamb; maintenance feeding; intramuscular fat}, issn = {1176-5283}, author = {PL Johnson and Knowler K and Mcrae KM and Bain WE and Pile G and Craigie CR and Rowe SJ} } @article {3672, title = {Is it possible to produce good quality meat from Holstein-Friesian bulls?}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {194-199}, address = {Lincoln}, abstract = {There is potential to increase the value of meat from Holstein-Friesian bulls by increasing the proportion of carcasses that are of suitable quality to be eligible for primal cuts sold in high-value markets. The objective of this study was to explore relationships between carcass and meat-quality traits from Holstein-Friesian bulls between 21-38 months of age, slaughtered on different occasions. Meat samples of M. longissimus lumborum were collected at slaughter and chill-aged at -1.5{\textordmasculine}C for seven days. The means ({\textpm}s.d.) were: carcass weight 313{\textpm}29 kg (n=256), dressing-out 54.7{\textpm}2.6\% (n=256), ultimate pH 5.9{\textpm}0.38 (n=221), shear force 11.34{\textpm}4.93 kgF (n=221), cook loss 28.4{\textpm}5.4\% (n=220) and colour indexes (n=159) L* (lightness) 36.06{\textpm}2.96, a* (redness) 12.38{\textpm}4.04 and b* (yellowness) 8.74{\textpm}2.24. A total of 80 samples (36\%) were found to be both of acceptable tenderness (below 10.9 kgF) and pH less than 5.8. Alleviating meat pH issues is required to ensure high-quality meat from bulls that is suitable for high-value primal cuts.}, issn = {1176-5283}, author = {Martin NP and Schreurs NM and Morris ST and McDade JL and Craigie CR and Hickson RE} } @conference {3672, title = {Intramuscular fat content of New Zealand lamb M. longissimus lumborum}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {77}, year = {2017}, month = {06/2017}, pages = {189-193}, address = {Rotorua}, abstract = {

The content of intramuscular fat (IMF\%) in lamb is an important trait for the lamb-meat value chain. Not only is IMF\% an import-ant energy reserve for replacement stock, IMF\% is an important driver of lamb-meat eating quality. A growing body of research shows an antagonistic relationship between muscle growth traits and fat content across the lamb carcass (including IMF\%). The New Zealand sheep industry has selected for muscle growth traits for decades to improve production efficiency and reduce extremes of carcass fatness historically observed, but the impacts on IMF\% levels in New Zealand lamb have not been widely investigated.

This paper aims to stimulate discussion on lamb IMF\% by reporting on levels of IMF\% observed in the M. longissimus lumborum (LL) of 1,705 progeny test lambs raised under extensive, pasture-based production systems across New Zealand, and investigates the relationship between IMF\% and carcass weight, VIAscan{\textregistered}-predicted GR (VSGR) and lean-meat-yield percentage (VSYLD).

The average IMF\% was 2.69\%, (SD = 0.83\%, and ranged between 0.91-6.42\%). IMF\% is positively correlated with carcass weight and VSGR and negatively correlated with VSYLD. Considerable variation exists in lamb IMF\%, highlighting the opportunity to manage IMF\% through genetic improvement and optimised on-farm management.

}, issn = {1176-5283}, author = {Craigie CR and Agnew MP and Stuart AD and Shorten PR and Reis MM and Taukiri KR and PL Johnson} } @conference {3672, title = {Assessing the meat quality of venison short-loin from farmed red deer using visible-near infrared spectroscopy}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {74}, year = {2014}, month = {06/2014}, pages = {17-22}, address = {Napier}, abstract = {Venison from red deer (Cervus elaphus) is marketed as a premium quality, healthy red meat. Ideally, meat-quality attributes need to be measured prior to sale. Near infrared spectroscopy (NIRS) has potential for the measurement of sensory, nutritional and technological parameters in beef, but its use on venison has not yet been considered. The aim was to evaluate NIRS for predicting Warner-Bratzler shear-force parameters, meat colour, ultimate pH, sarcomere length and water holding capacity of venison short-loins. Samples were halved, vacuum packaged, aged for either 3 or 42 d at 1{\textpm}1{\textdegree}C and frozen, then defrosted for meat-quality assessment and acquisition of spectral data. In total, 154 samples (3 and 42 d aged) were divided into calibration (75\%) and validation datasets (25\%). Using partial-least squares regression, calibration equations were tested on the validation dataset. Prediction accuracies ranged from R2 =8.3\%, (SEpred =2.42) for meat lightness to R2 =66.6\%, (SEpred =0.10) for ultimate pH, suggesting that NIRS maybe useful for predicting some venison quality parameters.}, issn = {1176-5283}, author = {Craigie CR and Purchas RW and Maltin CA and Roehe R and Morris ST} }