Concepts in Beef Cow Nutrition Aaron Stalker University of Nebraska-Lincoln

Introduction Feed costs –Major factor in economic efficiency Harvested forages –Majority of total feed costs

Annual operating costs per cow Northern Great Plains USDA, Economic Research Service, 2002 $419

Annual operating costs per cow Northern Great Plains USDA, Economic Research Service, 2002 $419 46%

Biological Priority for Nutrients Priority Function 1Maintenance 2Growth 3Milk Production 4Reproduction

Plant Cell PROTEIN SUGARS STARCH PECTINS FATS PRIMARY WALL SECONDARY WALL CELL CONTENTS CROSS SECTION

Inside SECONDARY WALL PRIMARY WALL CELLULOSE HEMICELLULOSE LIGNINACID DETERGENT FIBER (ADF) NEUTRAL DETERGENT FIBER (NDF) OUTSIDE

Ruminal Microorganisms n Ferment Structural Carbohydrates u Volatile Fatty Acids F Acetate, Propionate, Butyrate n Microbial Crude Protein

What is MP? n Metabolizable protein (MP) system (1996 NRC) u Acknowledges ruminal microorganisms F Protein (nitrogen) requirement F Separate from host u Degradable intake protein (DIP) F Fraction of total protein degraded in rumen u Primary source of nitrogen for microorganisms

What is MP? n Metabolizable protein (MP) system u Undegradable intake protein (UIP) F Fraction of total intake protein not degraded in rumen F Passes to small intestine u Metabolizable protein F Sum of digestible microbial protein and undegradable intake protein

Dietary Protein SMALL INTESTINE RUMEN

Dietary Protein SMALL INTESTINE

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein Undegraded Intake Protein aka Bypass or Escape

Dietary Protein SMALL INTESTINE Degradable Intake Protein Undegraded Intake Protein aka Bypass or Escape Metabolizable Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE Degradable Intake Protein

Dietary Protein SMALL INTESTINE

Demonstration of NRC software

Feed Costs Directly related to calving date Survey of cow calf producers –Western and North Central Nebraska –80% March-calving herd –Requires feeding hay 2427 kg per cow (Clark et al., 2004)

Reduce Harvested Forage Key Concepts –Cow nutrient requirements –Forage nutrient supply

Reduce Harvested Forage Key Concepts –Cow nutrient requirements –Forage nutrient supply

Metabolizable Protein Requirement of a 1200lb March-Calving Cow, 20 lb milk Peak Lactation Weaning Fetal Growth National Research Council, Nutrient Requirements of Beef Cattle, 1996

Biological Priority for Nutrients Priority Function 1Maintenance 2Growth 3Milk Production 4Reproduction

Potential metabolizable protein from native upland forage in Nebraska Sandhills Cow weighing 1200 lbs with 20 lbs peak milk, Adapted from Lardy et al., 2004

Metabolizable Protein Requirement of a March-Calving Cow and Forage Supply March Calving Cow weighing 1200 lbs with 20 lb peak milk production

Metabolizable Protein Requirement of a June-Calving Cow and Forage Supply June Calving Cow weighing 1200 lbs with 20 lb peak milk production

Hypothesis June-Calving –Annual operating costs decreased Extend grazing Limited Harvested Forage Match requirements with supply

Objectives Compare productivity –Traditional: March-calving –Extended Grazing: June-calving Develop net returns budgets

Study Site

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Materials and Methods 195 cows –75 March-calving: Traditional –120 June-calving: Extended Grazing First two years not included 4 Years of data –4 production cycles

Materials and Methods 195 cows –75 March-calving: Traditional –120 June-calving: Extended Grazing 60 breeding season on meadow 60 breeding season on upland range 4 Years of data –4 production cycles

Herd Management Traditional system –Fed hay mid-January through April Extended Grazing system –Fed supplement –Fed hay post-calving and winter storms

Weaning Calves weaned at 210 days of age –Traditional: March-born October –Extended Grazing: June-born January Pregnancy status determined Weaning rates

Post-weaning management Traditional: March-born –Grazed sub-irrigated meadow for 21 days Extended Grazing: June-born –Fed hay and supplement for 21 days

Economic analysis Budgets include actual costs of: –Harvesting hay –Purchased feed –Grazing Fence and water maintenance Monitoring livestock –Labor –Operating interest and overhead –Heifer replacement –Veterinary and medicine

Economic analysis (cont.) Budgets do not include costs of: –Land –Property taxes –Insurance –Buildings –Management

Statistical Analysis Experimental design –Completely randomized Experimental unit –Calving system Replication year

Statistical Analysis (cont.) Proc GLM SAS Single degree of freedom orthogonal contrasts: –Traditional vs. Extended Grazing All measured responses –Range vs. Meadow within Extended system Pregnancy rate Weaning rate

Results and Discussion

TraditionalExtended Grazing ItemRange Meadow Pregnancy Rate, % ab Weaning Rate, % ab a Means were similar (P>0.10) for Traditional vs. Extended Grazing. b Means were similar (P>0.10) for Range vs. Meadow within Extended Grazing system. Pregnancy and weaning rates of cows in Traditional and Extended Grazing systems

TraditionalExtended Grazing ItemRange Meadow Pregnancy Rate, % ab Weaning Rate, % ab a Means were similar (P>0.10) for Traditional vs. Extended Grazing. b Means were similar (P>0.10) for Range vs. Meadow within Extended Grazing system.

Weaning weight of calves in Traditional and Extended Grazing systems ItemTraditionalExtended Grazing Weaning weight, kg 220 a 189 b Gross value, $ Sale price, $/45 kg Cow cost/weaned calf, $ ab Means differ (P<0.05) for Traditional vs. Extended Grazing.

Gross value of calves in Traditional and Extended Grazing systems ItemTraditionalExtended Grazing Weaning weight, kg 220 a 189 b Gross value, $ Sale price, $/45 kg Cow cost/weaned calf, $ ab Means differ (P<0.05) for Traditional vs. Extended Grazing.

Seasonal price index of kg steer calves Source: USDA, Agricultural Marketing Service, western Nebraska-eastern Wyoming market , Nebraska auction markets

Seasonal price index of kg steer calves Source: USDA, Agricultural Marketing Service, western Nebraska-eastern Wyoming market , Nebraska auction markets

Seasonal price index of kg steer calves Source: USDA, Agricultural Marketing Service, western Nebraska-eastern Wyoming market , Nebraska auction markets

Steer calf price Source: USDA, Nebraska auction markets

Sale price of calves in Traditional and Extended Grazing systems ItemTraditionalExtended Grazing Weaning weight, kg 220 a 189 b Gross value, $ Sale price, $/45 kg Cow cost/weaned calf, $ ab Means differ (P<0.05) for Traditional vs. Extended Grazing.

Sale price of calves in Traditional and Extended Grazing systems ItemTraditionalExtended Grazing Weaning weight, kg 220 a 189 b Gross value, $ Sale price, $/45 kg Cow cost/weaned calf, $ ab Means differ (P<0.05) for Traditional vs. Extended Grazing.

Average resource use for Traditional and Extended Grazing cows over 4 years ItemTraditionalExtended Grazing Hay fed, kg Commercial Supplement, kg Grazing days Feeding labor, hour/head Calving labor, hour/head

Average resource use for Traditional and Extended Grazing cows over 4 years ItemTraditionalExtended Grazing Hay fed, kg Commercial Supplement, kg Grazing days Feeding labor, hour/head Calving labor, hour/head

Average resource use for Traditional and Extended Grazing cows over 4 years ItemTraditionalExtended Grazing Hay fed, kg Commercial Supplement, kg Grazing days Feeding labor, hour/head Calving labor, hour/head

Average resource use for Traditional and Extended Grazing cows over 4 years ItemTraditionalExtended Grazing Hay fed, kg Commercial Supplement, kg Grazing days Feeding labor, hour/head Calving labor, hour/head

Average resource use for Traditional and Extended Grazing cows over 4 years ItemTraditionalExtended Grazing Hay fed, kg Commercial Supplement, kg Grazing days Feeding labor, hour/head Calving labor, hour/head

Average post-weaning resource use for March and June born calves over 4 years ItemTraditionalExtended Grazing Feeding labor, hour/head Hay fed, kg- 200 Commercial Supplement, kg Grazing days21 -

Average post-weaning resource use for March and June born calves over 4 years ItemTraditionalExtended Grazing Feeding labor, hour/head Hay fed, kg- 200 Commercial Supplement, kg Grazing days21 -

Average post-weaning resource use for March and June born calves over 4 years ItemTraditionalExtended Grazing Feeding labor, hour/head Hay fed, kg- 200 Commercial Supplement, kg Grazing days21 -

Average post-weaning resource use for March and June born calves over 4 years ItemTraditionalExtended Grazing Feeding labor, hour/head Hay fed, kg- 200 Commercial Supplement, kg Grazing days21 -

Summary of Traditional and Extended Grazing systems Item Extended GrazingTraditionalDifference Gross value, $ Cow cost, $

Net returns per calf in Traditional and Extended Grazing systems Item Extended GrazingTraditionalDifference Gross value, $ Cow cost, $ Net returns$252$187$65

Conclusions Traditional vs. Extended Grazing system –Similar pregnancy rate –Similar weaning rate

Conclusions Traditional vs. Extended Grazing system –Weaned calf –Approximately equivalent value Seasonal price Price slide

Conclusions Traditional vs. Extended Grazing system –Extended Grazing Lower feed costs Greater net returns

Implications Changing calving date –Effective means of increasing net returns Match –Cow nutrient requirements –Forage nutrient supply Not March vs. June

Implications Date of calving varies –Geographic location –Forage resources

Metabolizable Protein Requirement of a 1200lb March-Calving Cow, 20 lb milk Peak Lactation Weaning Fetal Growth National Research Council, Nutrient Requirements of Beef Cattle, 1996

Metabolizable Protein Requirement of a 1200lb March-Calving Cow, 20 lb milk Peak Lactation Weaning Fetal Growth National Research Council, Nutrient Requirements of Beef Cattle, 1996

Metabolizable Protein Requirement of a March-Calving Cow and Forage Supply March Calving Cow weighing 1200 lbs with 20 lb peak milk production

Weaning Dates 8 weaning dates: –August 18, 1999 to November 24, 1999 –August 16, 2000 to November 22, 2000 (140 to 240 days after calving)

Effect of Weaning Date on Change in Cow Body Condition Score R 2 =.95

August weaning 1. No protein supplement during winter grazing 2. Protein supplement during winter grazing Weaning and Supplement Treatments for March Calving Cows November weaning 1. No protein supplement during winter grazing 2. Protein supplement during winter grazing

Effect of weaning date on cow body condition score

Effect of weaning date on pregnancy rate P = 0.56

Effect of weaning date on weaning weight P = <0.001

Effect of weaning date on carcass weight P = 0.56

Effect of supplement on cow body condition score

Effect of supplement on pregnancy rate P = 0.27

Effect of supplement on weaning weight P = <0.001

Effect of supplement on carcass weight P = 0.04

Effect of supplement on cow body condition score

P rotein supplement during winter grazing 1. Graze meadow pre breeding 2. Feed hay pre breeding No Protein supplement during winter grazing 1. Graze meadow pre breeding 2. Feed hay pre breeding Follow up study

Winter Protein Supplement No Protein Supplement

Spring Meadow Hay

Effect of supplement on cow body condition score *** **

Effect of supplement on pregnancy rate P = 0.46

Effect of supplement on percentage of live calves at weaning P = 0.02

Effect of supplement on calf weight P = 0.29 P = 0.02

Effect of supplement on carcass weight P = 0.23

Effect of meadow grazing on cow body condition score ***

Effect of meadow grazing on pregnancy rate P = 0.88

P = 0.15 Effect of meadow grazing on percentage of live calves at weaning

Effect of meadow grazing on calf weight P = 0.20 P = 0.01

Effect of meadow grazing on carcass weight P = 0.67

How much supplemental protein? Cows grazing native winter range, Nebraska Sandhills: 0.4 lb CP mid-late gestation (Dec-Feb) 0.6 lb CP 30 days pre-calving 1.0 lb CP days post calving

How much supplemental protein? Cows grazing native winter range, Nebraska Sandhills: 0.4 lb CP mid-late gestation (Dec-Feb) 1.5 lb DDG (as fed) 0.6 lb CP 30 days pre-calving 2.2 lb DDG (as fed) 1.0 lb CP days post calving 3.0 lb DDG (as fed)

How much supplemental protein? Cows grazing native winter range, Nebraska Sandhills: 0.4 lb CP mid-late gestation (Dec-Feb) 2.0 lb of CP in total diet 0.6 lb CP 30 days pre-calving 2.2 lbs of CP in total diet 1.0 lb CP days post calving 2.6 lbs of CP in total diet

Price Shop Calculate the cost per unit of the nutrient(s) you need. Evaluate other factors. Purchase in most economical way. EXAMPLE: $/Ton of Feed # of CP/Ton $200/ton of DDG 600# of CP/Ton DDG = $/lb of CP = $.33/lb of CP

Cost of Supplements $/Ton % CP Cost of CP Cottonseed Pellets % Cube (AN) % Liquid (16% NPN) % Tub % Cube % Alf. Hay (Lg Rd. ) % Alf. Hay

Feed Cost Calculator Ag manager’s tool box

A measure of energy reserves Influences animal –Reproduction/lactation –Feed efficiency/gain –Health –Maintenance requirements Scale 1 – 9 (emaciated to obese) Body Condition Score

BCS 2 Ribs and bone structure easily visible, but no signs of physical weakness.

BCS 3 Very thin. No visible fat is on the ribs or brisket. Individual muscles in the hindquarters are easily visible and spinous processes are very apparent.

BCS 5 There is less than 0.2 inches of fat over the ribeye. Last one or two ribs may be apparent. No fat is present in the brisket.

BCS 6 Appearance is smooth throughout. Some fat deposition is apparent in the brisket. Individual ribs are not visible.

BCS 7 Brisket is full. Tail head and pin bones have protruding deposits of fat on them. Back appears square due to fat.