A52-75-2007E.pdf - AgroMedia International Inc

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Milk Production7Characterization and regulation of the bovine stearoyl-CoAdesaturase gene promoterCorresponding AuthorZhao, F-Q.University of VermontCollaboratorsKeating, A.F.University of AlbertaKennelly, J.J.University of AlbertaBiochemical and Biophysical Research Communications (2006) Vol. 344 p. 233-240.Conjugated linoleic acid (CLA) refers to a number of 18 carbon fatty acidisomers having 2 double bonds with a single intervening single bond. BecauseCLAs and their precursors are produced by rumen microbes, CLAlevels in ruminant tissues are higher than those found in the tissues ofmonogastric animals. In cow’s milk, the cis-9, trans-11 isomer (9,11 CLA)predominates. Studies using experimental animals have revealed severalhealth benefits associated with dietary intake of 9,11 CLA. For this reason,there is interest in understanding the mechanisms controlling milk 9,11CLA content with the goal of increasing it to therapeutic levels. The majorityof 9,11 CLA in milk is produced in the mammary gland from trans vaccenicacid which is synthesized in the rumen. Stearoyl-CoA desaturase (Scd,sometimes referred to as delta-9 desaturase) is the enzyme responsible forthis transformation and the abundance of this enzyme affects the rate atwhich the transformation occurs. The objective of this study was to characterizethe genetic code responsible for controlling the synthesis of Scd.A ‘promoter’ region, designated as the Scd transcription enhancer element(STE), was found to have a critical role in activating the transcription ofthe Scd gene to produce the Scd enzyme. Using mammary cells in tissueculture, it was found that the addition of CLA reduced the rate of enzymesynthesis while insulin and oleic acid increased it. Both effects were mediatedthrough the activity of the STE.8Geographic and temporal aspects of an outbreak of off-flavours inbulk-tank milk in Prince Edward Island, CanadaCorresponding AuthorWichtel, J.J.Atlantic Veterinary CollegeCollaboratorsMounchili, A.Atlantic Veterinary CollegeSanchez, J.Atlantic Veterinary CollegePreventive Veterinary Medicine (2006) Vol. 74 p. 154-161.An outbreak of off-flavoured milk occurred in Prince Edward Island dairyherds between September 2000 and June 2002. An earlier study by theseauthors examined the risk factors associated with this outbreak. In the presentstudy, a novel statistical analysis (cluster-detection test) was applied todata collected during the outbreak in order to assess associations betweenoff-flavour incidents, farm location, time of outbreak and off-flavour characteristics.The analysis resulted in the discrimination of several discretetime-location-flavour clusters within the overall 21-month outbreak.102 Highlights in Canadian Dairy Cattle Research - 2007
Milk Production9Acetyl CoA carboxylase shares control of fatty acid synthesis withfatty acid synthase in bovine mammary homogenateCorresponding AuthorMcBride, B.W.University of GuelphCollaboratorsWright, T.C.University of GuelphCant, J.P.University of GuelphBrenna, J.T.Cornell UniversityJournal of Dairy Science (2006) Vol. 89 p. 2552-2558.Better understanding of the nutritional roles of various fatty acids (FA) hasprovoked attempts to alter the FA composition of milk fat, primarily throughchanging the cow’s diet. Many of these attempts have been successful inchanging the concentrations of specific FA with chain lengths of 16 carbonsor more due to the fact that about half of the 16 carbon FA and allof the longer chain FA in milk are absorbed directly from the bloodstream.However, the remaining FA in milk are synthesized in the mammary gland,limiting the effects that dietary changes can have on their concentrations.To effect changes in these FA, an understanding of the mechanisms bywhich they are synthesized is required. The objective of this study was todetermine the relative influence of the 2 primary enzymes involved in synthesizingthese FA in determining their rate of synthesis. Although it hadbeen thought that acetyl CoA carboxylase (ACC) was the enzyme that wasrate-limiting, results demonstrated that ACC and fatty acid synthase sharedcontrol over the rate of mammary short-chain FA synthesis.10Clinical trial to determine the productivity impact of milk ureanitrogen reportsCorresponding AuthorVanLeeuwen, J.A.Atlantic Veterinary CollegeCollaboratorsArunvipas, P.Atlantic Veterinary CollegeDohoo, I.R.Atlantic Veterinary CollegeKeefe, G.P.Atlantic Veterinary CollegeLissemore, K.D.University of GuelphBovine Practitioner (2006) Vol. 40 p. 86-94.Many Dairy Herd Improvement organizations provide milk urea nitrogen(MUN) testing as part of their regular service offerings. High MUN concentrationsare an indication of dietary imbalance. The objective of this studywas to determine whether MUN test results were of value to milk producers.Based on results of previous testing, 50 dairy farms with high MUN resultsand 30 farms with low MUN results in Prince Edward Island were randomlydivided into 2 groups (40 per group). For an 11-month period, one group(the intervention group) received monthly MUN test results and wereprovided with assistance in interpreting results and identifying possiblereasons for abnormal results when they occurred. The second group (thecontrol group) received their monthly MUN test results but were providedno assistance in their interpretation or application. Results, assessed duringthe last 3 months of the trial, revealed no differences in average MUN levelsor in standardized milk production between the 2 groups. However, herdsin the intervention group that made feed changes in response to interpretationof MUN results produced an average of 1.1 kg/day more milk in themonth after the feed change than herds that did not make a feed change.Most producers in the intervention group felt that MUN testing was at leastsomewhat useful as a nutritional management tool.Milk Production 103
Page 1 and 2:
Highlightsin Canadian Dairy Cattle
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Table ofContentsIntroduction.......
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ParticipantsListAgriculture and Agr
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Participants• P.E. Shewen• K.V.
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ParticipantsInternational Collabora
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ResearchSummaryIndexAnimal Welfare1
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Research Summary Index10 Associatio
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Research Summary Index57 Efficacy a
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Animal Welfare
Page 22 and 23:
Animal Welfare3Stall dimensions and
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Animal Welfare7Effects of milking o
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Animal Welfare11Effects of roughnes
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Environment1An approach for measuri
Page 31:
Environment4Methane and nitrous oxi
Page 35 and 36:
Feeding1Effects of alfalfa particle
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Feeding5Frequency of feed delivery
Page 39 and 40:
Feeding9Dietary forage and nonfiber
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Feeding13Effects of tannic acid and
Page 43 and 44:
Feeding17What is the true supply of
Page 45 and 46:
Feeding20Effect of ruminally protec
Page 47 and 48:
Feeding24Impact of B-vitamin supply
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Feeding28Responses to amino acid im
Page 51 and 52: Feeding31Lower pregnancy losses in
Page 53: Genetics
Page 56 and 57: Genetics2An iterative procedure for
Page 58 and 59: Genetics6Analysis of inbreeding and
Page 60 and 61: Genetics10Association of toll-like
Page 63 and 64: Health1Bacterial meningitis and enc
Page 65 and 66: Health5Synthetic peptide vaccinatio
Page 67 and 68: Health9Bovine toll-like receptor 9:
Page 69 and 70: Health13Immunization with plasmid D
Page 71 and 72: Health17Progress in the development
Page 73 and 74: Health21Immune response to Staphylo
Page 75 and 76: Health24Genotype and subtype analys
Page 77 and 78: Health27Activation of the hypothala
Page 79 and 80: Health30Influence of the genotype o
Page 81 and 82: Health34Agreement between three ELI
Page 83 and 84: Health38Prevention of fatty liver i
Page 85 and 86: Health41The cell-mediated immune re
Page 87 and 88: Health45A comparison of serum harve
Page 89 and 90: Health48Effects of prepartum intram
Page 91 and 92: Health51Bovine whey proteins inhibi
Page 93 and 94: Health55DNA-protein immunization ag
Page 95 and 96: Health59Formulation with CpG oligod
Page 97: Milk Production
Page 100 and 101: Milk Production317β-estradiol redu
Page 105: Reproduction
Page 108 and 109: Reproduction3Follicular fluid conce
Page 110 and 111: Reproduction6The impact of chromoso
Page 112 and 113: Reproduction10Spontaneous uptake of
Page 114 and 115: Reproduction14Characterization of l
Page 116 and 117: Reproduction17Expression of phospho
Page 118 and 119: Reproduction21Regulation of serine
Page 120 and 121: Reproduction25 Na+ /K + ATPase as a
Page 123: Author Index
Page 126 and 127: Author IndexBrownlie, R. Health 6..
Page 128 and 129: Author IndexKeefe, G.P. Health 10..
Page 130 and 131: Author IndexPerez-Casal, J. Health
Page 132: Author IndexZadoks, R.N. Health 47.
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