Intake by Feedlot Cattle

Transcription

1 Intake by Feedlot Cattle Judson Vasconcelos, DVM, PhD Assc. Sr. Technical Consultant Global Cattle Marketing Elanco Animal Health

2 Objectives Review of basic concepts of intake by feedlot cattle. Evaluation of recent methods of intake prediction. Review of current data on intake of feedlot cattle.

3 Intake Basic Concepts The animal s productivity depends on feed amount and efficiency of digestion and metabolism. The dry matter intake affects animal performance. To manage DMI to optimize NEg intake is the main goal of nutritionists.

4 Factors that affect intake 1) Animal 2) Environment 3) Diet 4) Management

5 BW Factors that affect intake Animal BW is a key-factor for intake prediction. Galyean and Hubbert (1992): BW explained 59.78% of intake variation in diets with different energy levels. Commercial feedlots: In diets containing NEg of 1.1 to 1.59 Mcal/kg, BW explained 57.1 to 45.2% of the variation, respectively.

6 Factors that affect intake Animal Body composition The body composition changes during the feeding period. The protein and water deposition rate decrease during the finishing period.

7 Factors that affect intake Animal Body composition The amount of body fat is another key-factor on intake control. Intake lipostatic modulators are observed in intake curves in feedlots, which show decreased intake by the end of the finishing period. Leptin is a key-hormone in this regulation. The white adipose tissue produces leptin, which binds to specific receptors in the brain.

8 Leptin CNS (Hypothalamus) Hunger Leptin Adipose Tissue

9 Leptin Factors that affect intake Animal Hersom et al. (2004) observed that leptin concentrations increased 175% on days 26 to 86 in finishing steers. Fox et al. (1988): Intake decreased 2.7% for each increase of 1% in the amount of fat in intervals of 21.3 to 31.5% of body fat.

10 Factors that affect intake Animal Hersom et al. (2004); JAS

11 Factors that affect intake Animal Hersom et al. (2004); JAS

12 Lighter arrival weight cattle have a more steady increase in intake by days on feed. Heavier arrival weight cattle bump up quickly to a saturation point for a while and then decrease toward the end of feeding. The latter relationship shows 3 segments of the feeding period (adaptation, plateau, and retard phase).

13 Factors that affect intake Animal Sex Breed Age Size Previous nutrition Dynamics of rumen microbial popupaltion Feeding behavior Compensatory gain Intake level Energy level

14 Factors that affect intake Management Bunk management Implants Animal management Health Pen conditions Transport

15 Factors that affect intake Management Intake behavior Animal predisposition to acidosis could be related to intake rate and meal size. Cyclic intake happens in animals with ruminal acidosis, decreasing performance (Schwartzkopf-Genswein et al., 2003). Non-uniform intake (separation, bad mixture) can influence in the ability that animals have of keeping a healthy ph.

16 Factors that affect intake Management Bunk management Goal: Mantain or increase intake Similar or better feed conversion Decreased waste Control of amount fed

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20 Manejo Alimentar Dias de Trato Consumo de MS, kg/cabeça

21 Factors that affect intake Management Hubbert (2008)

22 Factors that affect intake Management Hubbert (2008)

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26 Factors that affect intake Diet

27 Intake Basic Concepts Increased intake = Increased ADG. Factors that affect intake are complex and multi-factorial. Rumen fill. Metabolic (calories or other chemical factors). Physiologic.

28 Factors that affect intake Diet Added roughage = decreased digestive upsets and maximized NEg intake Vasconcelos and Galyean (2007) Roughage level: 0 to 13.5% (mode: 9% [summer] and 10% [winter]) Common sources: Corn silage and alfalfa hay Small increases in roughage level = increased DMI Substitution with bulkier (higher NDF) roughage sources increased DMI by feedlot cattle The reasons are not fully understood

29 Dry Matter Intake vs. Dietary NDF Concentration Arelovich et al. (2009) Galyean and Vasconcelos (2008)

30 NEg Intake vs. Dietary NDF Concentration Arelovich et al. (2009) Galyean and Vasconcelos (2008)

31 NEg Dry Intake Matter per unit Intake DMI vs. vs. Dietary NDF NDF Concentration Concentration from Roughage Arelovich et al. (2009) Galyean and Vasconcelos (2008)

32 NEg Intake vs. NDF Concentration from Roughage Arelovich et al. (2009) Galyean and Vasconcelos (2008)

33 Intake Given that DMI was highly related to dietary NDF concentration in our beef cattle database and NEg intake per unit DMI was not related to NDF concentration, one could infer that DMI would not be highly related to NEg intake per unit of DMI or to other measures of feed efficiency. ARELOVICH ET AL. (2008)

34 Intake prediction Evaluation of NRC (1996) equations for intake prediction and relationship with performance Four years of data. Three feedlots in the US. Data obtained: 1) animal performance. 2) diet composition. 3) ingredients DM. 4) days in each ration. 5) DM fed daily. McMeniman et al. (2009)

35 Intake prediction Relationship between observed and predicted DMI by NRC (1996) with initial BWbased equations for 3363 pens of cattle in a commercial feedlot database. McMeniman et al. (2009)

36 Intake prediction Plot of year x feedlot x season adjusted: ADG vs. NEg intake for 3363 pens of cattle in a commercial feedlot database. McMeniman et al. (2009)

37 Intake prediction Plot of year x feedlot x season adjusted: G:F vs. NEg intake for 3363 pens of cattle in a commercial feedlot database. McMeniman et al. (2009)

38 Intake prediction Interactions between numerous dietary, animal, environmental, and management factors. Biases observed in evaluation of NRC equations. Development of feedlot-specific prediction equations. More accurate and precise method for predicting DMI by feedlot cattle.

39 Intake prediction These evaluations of DMI indicated the shortcomings of current published equations for predicting DMI. ADG increased with NEg, but conversion was not affected. These findings suggest a diminishing return effect of energy intake on energy retention.

40 Questions and Comments Judson Vasconcelos, DVM, PhD Assc. Sr. Technical Consultant Global Cattle Marketing Elanco Animal Health 2001 W. Main Street, P.O. Box 708 Greenfield, IN 46140