ANSC 318 1st Edition Lecture 18 Outline of Last Lecture I Economic values for cattle and energy requirements of beef cows Outline of Current Lecture II Protein Requirements for Beef Cows III Mineral Requirements for Beef Cows a Trace Mineral Nutrition IV Body Conditioning Scores V Feeding Beef Cattle a Impact of Forage Quality b Selecting Supplements Current Lecture Protein Requirements for Beef Cows Protein is needed for maintenance pregnancy lactation and growth for 1 st and 2nd calf cows only Mineral Requirements Fertility P Cu Zn Se Mn Appetite Mg K Zn Cu Nervous System Mg P Cu Fetal Development Cu Zn Se Mn Disease Resistance Cu Zn Se Hair Coat Cu Zn Se Skin and Hoof Health Zn Milk Production Ca P Mg Muscle Development P S Zn Se Bone Development Ca P Mg Mn Cu Macrominerals Macromineral Gestating Cows Lactating Cows Maximum Limit Calcium 1 6 x P 1 6 x P 2 0 Phophorous 0 17 0 24 1 0 Potassium 0 70 0 80 3 0 Magnesium 0 15 0 22 0 40 Sodium 0 10 0 15 These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Chlorine 0 25 0 30 Sulfur 0 15 0 15 0 40 Calcium and Phosphorous are the most likely to be deficient Magnesium deficiency grass tetany Sodium and Chloride salt Sulfur is not usually deficient and is often too high above 0 30 will impair Copper absorption Microminerals Micromineral Gestating Cow Lactating Cow Maximum Limit Copper ppm 17 17 100 Zinc ppm 60 60 500 Manganese ppm 70 70 1 000 Selenium ppm 0 20 0 30 2 Cobalt ppm 0 20 0 20 10 Iodine ppm 0 60 0 60 50 Iron ppm 87 87 1 000 Cu Zn and Se are most likely to be deficient When Cu is deficient the pigment of hair can be dulled average levels of most forages are below the requirement line for Zn and Cu Enhanced Bull Fertility Cu Mn Zn Se Vitamin E Enhanced Cow Fertility Immunity Mastitis Cu Mn Zn Se Vitamin E Maternal Selenium Vitamin E Supplements shorten the days to estrus after calving making rebreeding the cow a faster process they also have a positive effect on fertility Maternal Trace Mineral Nutrition o Enhanced Cold Tolerance Cu Se I o Enhanced Immune System Colostral Antibody Transfer Cu Co Se Vitamin E Mineral Supplementation for Beef Cows free choice meals blocks tubs liquid supplements limit fed energy protein supplements injectable vitamin A D E and trace minerals Vitamin Requirements for Beef Cows Vitamins A D and E need to be supplemented water soluble vitamins generally do not need supplementation vitamin A D and E supplementation is especially critical when green forages are not available Vitamin A D and E Sources green forages or hay synthetic sources for use in feed supplements injectable vitamins sunlight vitamin D only Vitamin Vitamin A Vitamin D Vitamin E Animal Class Feedlot Gestating Cow Lactating Cow All Cattle All Cattle Requirement 2 200 2 800 3 900 275 15 to 60 Critical vs Noncritical Stages of Production 1 Calving to Breeding early lactation high milk production preparing for cow rebreeding adding weight 2 Breeding to Weaning late lactation lower milk production slow fetal growth 3 Weaning to start of late gestation slow fetal growth no milk production 4 Late gestation rapid fetal growth Ranked highest to lowest 1 2 4 3 Most critical high to low 1 4 2 3 The critical periods 1 and 4 last about 3 months each Body Conditioning Scores management tool to estimate body fat reserves in cows used to monitor cow s energy status not an effective management tool to access protein vitamins or mineral status of cows Scores Range from 1 9 BCS 3 thin ribs and backbone are visible BCS 5 moderate ribs not visible and evidence of fat cover on each side of tail head BCS 7 Borderline fat fleshy appearance and abundant fat cover on both sides of tail head Feeding Beef Cattle Underfeeding Energy During Late Gestation Period 4 Impact on cow reproductive performance Beef cows with low BCS 4 at calving cows less likely to reach sufficient body condition during early lactation to have good reproductive success lower pregnancy rates conceive later in breeding season increased cattle interval Underfeeding Energy During Late Gestation Period 4 Impact on calf survival Calves born to low energy heifers lighter at birth lower survival rate at birth and during neonatal period higher death losses due to scours Underfeeding Energy During Late Gestation Period 4 Impact on calving difficulty in heifers Underfeeding Energy During Late Gestation Period 4 Impact on weak calf syndrome Calves born to low protein dams weaker and slower to suckle more susceptible to pathogens and cold stress higher incidence of morbidity and mortality Underfeeding Energy During Postcalving Period 1 Impact on cow productivity cows with low BCS 4 at start of breeding delayed return to estrus following calving reduced pregnancy rates conceive later in the breeding season increased calving interval lower milk production weaning BW minor decreased protein decreased time to estrus 85 days from calving to breeding is ideal Impact of Forage Quality increased protein increased DMI drops off with low protein because rumen microbes are being starved of ammonia increased fiber decreased DMI Best Way to Evaluate Forage Quality TDN CP Ratio forage TDN CP ratio TDN CP ideal TDN CP ratio for rumen microbes 4 to 5 1 DMI of forage is negatively related to TDN CP ratio threshold 7 1 if above there will not be enough CP Supplementation Programs for Grazing Beef Cattle Decision Process 1 determine cow s requirements weight Breed Pregnant macro and microminerals 2 evaluate forage quality TDN CP 3 select supplement based on ideal TDN CP select low TDN CP supplements for low quality forage 4 determine target level of supplement intake supplement intake shouldn t exceed 0 5 of BW 5 select method of supplementation based on costs and labor Types of Supplements for Grazing Beef Cattle meal supplements liquid supplements cube supplements block supplements tub supplements Ionophores Rumensin monensin Bovatec lasalocid and Gain Pro bambermycin rumensin improves feed efficiency in finishing cattle fed high grain diets 5 7 and forage fed cattle 14 16 underutilized as a management tool to improve feed efficiency of grazing cattle alter rumen fermentation beef cows fed rumensin consumed 10 less hay while maintaining similar BW gains and reproductive performance