Protein and methionine hydroxy analog for lactating cows.
A 2 X 2 factorial experiment (protein 12.5 and 15.5; methionine hydroxy analog 0 and .125% dry matter) included 144 cows for one complete lactation, distributed over seven locations. Rations were formulated to the desired protein, methionine analog, and constant amounts of fiber 17%, sulfur .225%, calcium .6%, phosphorus .4%, and salt .5%. Treatment effects were not apparent for dry matter intake, daily milk and fat-corrected milk production, conversion of energy, and body weight changes. Conversion of dietary crude protein into milk protein was 34.5% for the low and 25.8% for the high protein ration. Methionine analon (0% = 2.54; .125% = 1.90). Effect of methionine analog was most apparent at low protein as 0 analog cows produced 247 kg fat, required 2.9 services/contraception, and had 156 days open whereas cows on other treatments (.125% analog and/or high protein) produced 264 kg fat, required 1.8 to 2.2 services/conception, and had 124 to 134 days open. Methionine analog response is discussed in relation to tuminal and postruminal effects as well as the interrelation with protein and energy.
D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000378:metabolism*; D004043:Dietary Fiber; D004044:Dietary Proteins; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006885:Hydroxybutyrates / Q000378:metabolism*; D007774:Lactation; D050356:Lipid Metabolism; D008715:Methionine / Q000031:analogs & derivatives; D008892:Milk / Q000378:metabolism; D011247:Pregnancy; D011488:Protein Deficiency / Q000378:metabolism; D012098:Reproduction; D013438:Sulfhydryl Compounds / Q000378:metabolism
D004043:Dietary Fiber; D004044:Dietary Proteins; D006885:Hydroxybutyrates; D013438:Sulfhydryl Compounds; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine