Voluntary feed intakes of Feeds Department of Animal Science, Faculty of Agriculture Khon Kaen University Prof. Dr. Metha Wanapat Dr. Anusorn Cherdthong Tropical Feed Resources and Feeding Technology

Voluntary feed intake Voluntary feed intake (VFI), voluntary dry matter intake (VDMI) Amount of feed which animals are allowed to adapt for suitable time to consume such feed until consistent level achieved and measured when feed is given on ad libitum basis and about 10% of feed remaining

Intake Essential factor to measure uptake of feeds and nutrients by animal measured as –kg DM/hd/d –% of body weight /hd/d –g/W.75 /hd/d

* * * * * * ** * * * * Intake increase as adaptation time advances Roughage Intake Kg/d Adaptation of ruminants to obtain consistent DM intake of roughages Day * *

Palatability and Taste Responses which animals show in accepting and consuming any given feeds Influenced by numerous factors: sight/visual, smell, flavors, tastes, chemical compositions etc

Regulation of feed intake Short-term control long-term control Current concept: energy intake will be regulated to maintain consistent level of lipids stored in adipose tissue in adult animals adult animals tended to adapt to high energy diets in order to maintain consistent level of body stored lipids

The various mechanisms postulated to regulate voluntary intake. --Energy balance is governed by the input of digestible nutrients, the output, and the cost of work of digestion and metabolism. --Hormonal factors in blood are a composite of responses to absorbed nutrients, components that regulate mobilization of energy from depot in case of negative energy balance, and the factors secreted by the anterior pituitary the regulates eating. --The central nervous system (CNS) and hormones regulate gastrointestinal motility and probably passage, causing some alleviation of fill by passing coarser material at higher intakes and set points

The more the feeds can be digested, the higher feed intake will be, well true in roughages but not for concentrates Ad libitum feeding will result in best measure of roughage intake Adaptation period for any animals / species should be given and will be variable

CNS Sight Odour Taste Texture Gl tract Mechanoreceptors Chemoreceptors Blood-borne Liver Hindbrain Body Adipose Muscle FOOD DIGESTA NUTRIENTS STORES Eating Digestion Metabolism Time Regulation of feed intake

Receptors CNS Feeding behavior Feed intake Digestion absorption VFA + energy balance - Fill Time limit Rumination Passage Hormones mobilization Output maintenance growth, work lact., stress Appetite set point integration Hypothalamus Work of digestion Regulation of feed intake

Feedback for energy balance regulation Lipostasis –balance of stored fat –fat animals eat less than thin animals Humoral factors –Central nervous system (CNS) regulates energy balance by receptors –CNS regulates –Hunger-physiological and psychological state resulting in initiation of feeding –Satiety-opposite to Hunger, resulting in termination of feeding

Factors affecting on voluntary feed intake Rumen distention/gut-fill –the ability of rumen to expand to fill in feed particles until compacts and depends on feed bulkiness Rumen conditions –pH < 6.0 intake < 5.5severe intake - VFAs C 2 > C 3 > C 4 intake

Chemostatic factor –rumen VFAS –plasma VFAS Thermostatic factor –rumen temperature intake –body tempereture intake

Distension/Gut Fill Thermostatic Chemostatic (VFA) DMI DM Intake. g/kg W % TDN Nutritive value Relationship between DM roughage intake (DMI), digestible energy intake (DEI) and nutritive value DEI Inflection point In the tropics

Strategies to improve feed intake of roughage Treatment / processing supplementation –concentrates –strategic supplement

Supplementation and substitution effects Concentrate supplementation Roughage intake, %BW Kg/hd/d

Treatments of Roughages Physical treatment –Chopping –Grinding –Pelletting –Watering –Cubing

Chemical treatment NaOH Ca(OH) 2 Aqueous NH 3 (NH 4 OH) Anhydrous NH 3 Urine Urea

Biological treatment White-rot fungi mushroom culture industrial enzymes : cellulase, pectinase, xylanase etc

Caloric density (CD) CD = DE x D kcal/ml DE = kcal/g D = density of ground feed when replaced in water, g/ml

Mean milk yield Mean DM intake Mean body weight Lactation, month Trends in milk production, DM intake, body weight change in lactating dairy cows BW,kg DM intake kg/d Milk yield kg/d

kg milk REQUIREMENT POR : 630 KG COW 45 kg milk 27 kg milk 18 kg milk 9 kg milk Ration DE X D, Kcal / ml Digestide energy intake (Kcal/W kg 3/4 )

Problems in feeding lactating dairy cows Low DM intake of roughages Low quality of roughages low overall DM intake during peak milk persistency low milk yield and milk quality, fat, protein, solids-not-fat (SNF)

Possible solutions/ strategies of feeding Increase roughage intake Improve roughage quality treatment/supplementation improve rumen ecology and fermentation efficiency Manipulate VFAs microbial protein synthesis etc

Good luck!!!