658 KB52 KB200420252023Chimonyo, MichaelDhliwayo, MarshallMatope, AlphonceTivapasi, MusavengaZindove, Titus Jairusštevilka:111 str.letnik:119COBISSID_HOST:154876419ISSN:1854-1941URN:URN:NBN:SI:doc-JI85CNUKenZaložba Univerze v LjubljaniActa agriculturae Slovenicaarid rangelandsbeef cattlebody framebreedsconformation traitsfiziološki parametrigovedograzingheat stressMashonamesne pasmeokvirpašaphysiological parameterspolsušno okoljesemi-arid rangelandssušno okoljetelesne lastnostivročinski stresHeat tolerance in Mashona beef cows in semi-arid rangelands: does con-formation matter?|High temperatures and frequent heat waves raise concerns about heat stress in cattle in grass-based systems, especially in arid and semiarid areas. This study analysed the relationship between conformation traits and physiological pa-rameters associated with heat stress in Mashona cattle. A total of 200 records from fifty cows were used to study the relation-ships between seven conformation traits and physiological pa-rameters associated with heat stress. Body conformation traits were categorised into three principal components related to body capacity (body depth, flank circumference, chest girth), frame size (stature and body length), and loose skin fold (navel height and dewlap size). As the size of abdominopelvic and tho-racic cavities increased, respiratory rate, heart rate, and rectal temperature decreased significantly, while blood triiodothyro-nine concentration increased. Cattle with deeper bodies, larger flanks, and larger chest girths had significantly lower heart rate, respiratory rate, and rectal temperature but higher blood tri-iodothyronine concentration than cattle with shallower bod-ies, smaller flanks, and smaller chest girths. Respiratory rate increased with increasing frame size. Large-framed cattle had significantly higher respiratory rate and lower blood thyroxine concentration. Small-framed cattle with larger chest girth, larg-er dewlap, and navel farther from the ground surface are better adapted to higher ambient temperaturesVisoke temperature in pogosti vročinski valovi povečujejo nevarnost vročinskega stresa pri govedu na paši, zlasti v sušnih in polsušnih okoljih. Raziskava je analizirala povezave med telesnimi lastnostmi goveda pasme mashona in fiziološkimi parametri, povezanimi z vročinskim stresom. Skupno 200 meritev, pridobljenih na petdesetih kravah, je bilo uporabljenih za preučevanje povezave med sedmimi telesnimi lastnostmi in različnimi fiziološkimi parametri, povezanimi z vročinskim stresom. Telesne lastnosti so bile razvrščene v tri kategorije, ki se nanašajo na obseg telesa (globina telesa, obseg trebuha, prsni obseg), velikost okvira (višina križa in dolžina telesa) in viseči kožni gubi (višina popka in velikost podgrline). S povečevanjem velikosti prsne in trebušne votline se je zmanj-ševala frekvenca dihanja, srčni utrip in rektalna temperatura, koncentracija trijodtironina v krvi pa se je povečevala. Govedo z večjo globino telesa, in večjim obsegom trebuha ter prsnega koša je imelo nižji srčni utrip, frekvenco dihanja in rektalno temperaturo, vendar višjo koncentracijo trijodotironina v krvi kot govedo s plitvejšim telesom, in manjšim obsegom trebuha ter prsnega koša. S povečevanjem velikosti okvira se je poveče-vala frekvenca dihanja. Živali z velikim okvirom so imele zna-tno manjšo frekvenco dihanja in nižjo koncentracijo tiroksina v krvi. Živali manjšega okvira z večjim prsnim obsegom, večjo podgrlino in popkom, bolj oddaljenim od površine tal, so bolje prilagojene na višje temperature okoljaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Biotehniška fakulteta