title: Heat energy for growing goats and sheep grazing different pastures in the summer.
abstract: Angora goat, Spanish goat, and Suffolk x Rambouillet sheep wethers (20 of each type; 30.4+/-.57, 31.3+/-.93, and 32.4+/-1.08 kg BW for Angora goats, Spanish goats, and sheep, respectively) were used to investigate influences of animal type and two grass-based pasture treatments on heat energy during summer grazing (mid-August through September in Oklahoma). The improved pasture treatment consisted of .7-ha paddocks primarily of Old World bluestem and johnsongrass, whereas the native pasture treatment entailed 10.8-ha paddocks dominated by big and little bluestems and indiangrass. Grasses were 95 to 100% of diets for the improved pasture treatment and 71 to 95% for the native pasture treatment; forbs were 2 to 25%, and shrubs were less than 4% of diets for the native pasture treatment. Metabolizable energy intake was similar (P > . 10) between pasture treatments but differed (P <.01) among animal types: 79, 99, and 113 kcal/(kg(.75) BW.d) for Angora goats, Spanish goats, and sheep, respectively; SE 7.1. Heat energy estimated via CO2 entry rate was affected by pasture treatment ( P = .08) and animal type (P < .001): improved pasture treatment 109, 132, and 151 kcal/(kg(.75) BW.d); native pasture treatment 126, 138, and 163 kcal/(kg(.75) BW.d) for Angora goats, Spanish goats, and sheep, respectively. Likewise, daylight grazing time was greater (P = .04) for the native than for the improved pasture treatment and differed (P < .01) among animal types: improved pasture treatment 5.3, 4.7, and 6.7 h; native pasture treatment 6.0, 5.7, and 8.1 h for Angora goats, Spanish goats, and sheep, respectively. In conclusion, heat energy during summer grazing of grass-based paddocks was less for goats than for sheep, and animal type can affect the increase in heat energy as energy intake and grazing time increase.
authors.affiliation: E (Kika) de la Garza Institute for Goat Research, Langston University, OK 73050, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Herselman
authors.forename: S P
authors.initials: SP
authors.lastname: Hart
authors.forename: T
authors.initials: T
authors.lastname: Sahlu
authors.forename: S W
authors.initials: SW
authors.lastname: Coleman
authors.forename: A L
authors.initials: AL
authors.lastname: Goetsch
mesh_terms: D000821:Animal Feed; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D004734:Energy Metabolism; D005260:Female; D006041:Goats / Q000254:growth & development*; D006358:Hot Temperature; D012621:Seasons; D012756:Sheep / Q000254:growth & development*
chemical_list: D002245:Carbon Dioxide