@article {3672, title = {BRIEF COMMUNICATION: Carcass characteristics and meat quality of early, mid- and late-season commercial lambs}, journal = {New Zealand Journal of Animal Science and Production}, volume = {79}, year = {2019}, month = {07/2019}, pages = {80-83}, address = {Palmerston North}, abstract = {Comparisons were made of carcass and meat quality characteristics of three groups of wether lambs (n=15/group): a composite breed slaughtered at weaning (EARLY), and at 6-8 months of age (MID) and Merino lambs slaughtered at 12 months of age (LATE). Carcass weight and eye muscle area were measured and meat quality was measured on the Longissimus thoracis (loin). All lambs had similar carcass weights (18.7-19.0 kg; P>0.05). Meat from LATE lambs had higher ultimate pH and intramuscular fat \% (P<0.001) than EARLY and MID lambs. Loins from EARLY lambs had lower Chroma (P<0.01), higher eye muscle area (P<0.001) and shear force (P<0.05) and greater percentage of polyunsaturated fatty acids (P<0.001) than loins from MID and LATE lambs. Although statistical differences were observed in meat quality measurements, differences in absolute values suggest that the three production systems resulted in minor variation in meat quality.}, issn = {1176-5283}, author = {Ye Y and Schreurs NM and PL Johnson and Corner-Thomas RA and Agnew MP and Silcock P and Eyres GT and Maclennan G and Realini CE} } @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 {41837, title = {Repeatability of fatty acid composition in pm:am milk samples from cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {297-299}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {The present study was designed to estimate the repeatability of fatty acid composition in cows{\textquoteright} milk collected at a pm:am herd test. As part of a larger project, whole milk was collected during a routine herd test in March 2003 from 10 Friesian and 10 Jersey cows at Flock House, in the evening and again the following morning. Fat in the 40 samples was separated by centrifugation, fatty acids were converted to their methyl esters, and individual fatty acid percentages in each sample were assayed by gas chromatography. In general, the fatty acid composition of milk was very similar at the pm and am samplings. For the fatty acids making the largest contributions (10 to 29\% of the total) to fatty acids present in milk (C14:0, C16:0, C18:0 and C18:1 cis-9 (oleic)) and for conjugated linoleic acid and the Mono- Unsaturated/Saturated ratio, pooled within-breed correlations of compositions between pm and am milk samples were high (0.76, 0.80, 0.88, 0.76, 0.75 and 0.74, respectively; standard errors 0.06 to 0.12). The pm:am correlation, averaged over the most abundant 15 fatty acids in milk, was 0.77 {\textpm} 0.10. It is concluded that a single milk sample or a pooled pm:am sample is adequate for estimating the composition of the predominant fatty acids. KEYWORDS: milk; fatty acid; cows; repeatability. }, issn = {1176-5283}, author = {Morris CA and Hickey SM and Agnew MP} }