Kimwe mu byatangaje abashakashatsi ni uko inka zishobora kugira inshuti zihariye, zigahitamo kubana na zo kurusha izindi, kandi kuzitandukanya bikazigirira ingaruka zigaragara ku buzima n'imyitwarire.
Bumwe mu bushakashatsi bwakunzwe kuvugwa cyane kuri iyi ngingo bwakozwe n'abashakashatsi bo muri University of Northampton mu Bwongereza, buyobowe na Dr. Krista McLennan.
Ubwo bushakashatsi, bwatangajwe mu mwaka wa 2008 mu kinyamakuru cy'ubushakashatsi cya Applied Animal Behaviour Science, bwari bugamije kumenya niba inka zifite ubushobozi bwo kugirana umubano wihariye n'izindi nka, n'ingaruka zibaho iyo zitandukanyijwe.
Abashakashatsi bakurikiranye imyitwarire y'inka ziba mu matsinda, bareba uburyo zibana mu buzima bwa buri munsi. Basanze buri nka yaragiraga izo yikundira kurusha izindi, aho zabaga zegeranye igihe zirisha, ziryamye, zitembera, cyangwa ziri kuruhuka.
Mu rwego rwo kumenya niba koko izo nka zari zifitanye isano idasanzwe, abashakashatsi bazishyize ahantu hatandukanye. Rimwe bazishyiraga hamwe n'inka zisanzwe ziziranye, ubundi bakazitandukanya bakazihuza n'inka zitari zisanzwe zibana na zo.
Muri icyo gihe bapimaga: umuvuduko w'umutima (heart rate), imyitwarire yazo, ndetse n’urwego rw'ituze cyangwa guhangayika.
Ibyavuye muri ubwo bushakashatsi byatangaje benshi. Abashakashatsi basanze iyo inka yabaga iri kumwe n'iyo isanzwe ikunda: umutima wayo warateraga ku muvuduko usanzwe, ituje, ndetse imyitwarire yaya ari isanzwe.
Ariko iyo yatandukanaga n'inshuti yayo: umuvuduko w'umutima warazamukaga, yagaragazaga ibimenyetso byo guhangayika, yabaga idatuje kandi ikora amakosa menshi mu bizamini byoroheje byayikorerwagaho.
Dr. Krista McLennan yavuze ko ibi byerekanye ko kuba hafi y'inka zisanzwe zimenyeranye bifasha kugabanya stress, kimwe n'uko bimeze ku bantu cyangwa ku zindi nyamaswa zibana mu matsinda.
Nyuma y'ubwo bushakashatsi, abandi bashakashatsi bo muri University of British Columbia muri Canada ndetse n'ikigo Animal Welfare Program bakoze ubushakashatsi ku mibanire y'inyana n'inka nkuru.
Basanze inyana zirerewe hamwe n'izindi zigaragaza: kwiga vuba, kudatinya ibintu bishya, ndetse no kugira ituze kurusha izarerwa zonyine.
Ubushakashatsi bwasohotse mu binyamakuru nka Frontiers in Veterinary Science na Journal of Dairy Science bwerekanye ko kubuza inka kubana n'izo zisanzwe zimenyereye bishobora kugira ingaruka ku mibereho yazo no ku musaruro wazo.
Abahanga bavuga ko inka ari inyamaswa zibaho mu matsinda (social animals).
Mu gasozi, kubana mu matsinda byazifashaga: kwirinda inyamaswa z'inkazi, kurinda inyana zazo, gufatanya gushakisha ubwatsi no kubona amazi, no kugabanya ubwoba.
Ni yo mpamvu n'ubu, n'ubwo zororerwa mu bworozi bugezweho, zigikomeza kugira uwo zikunda kubana na we kurusha abandi.
Kuzitandukanya bishobora kugira izihe ngaruka?
Iyo inka zitandukanyijwe n'inshuti zazo z'igihe kirekire, ubushakashatsi bwagaragaje ko zishobora:
- Kwabira cyane zishaka izo zatandukanye na zo.
- Kugabanya uko zirya.
- Kugira umunaniro cyangwa guhangayika.
- Guhora zishakisha aho ya nka zikunda yagiye.
- Kugira impinduka ku musaruro w'amata mu gihe runaka, bitewe n'igipimo cy'igitutu yagize.
Abahanga bavuga ko izo ngaruka ziterwa n'uko gutandukana n'inka yari isanzwe imenyereye bihungabanya ubuzima busanzwe bwayo.
Ni iki ubu bushakashatsi bwahinduye?
Ibyavuye muri ubu bushakashatsi byatumye ibihugu byinshi n'abahanga mu bworozi batangira gushishikariza aborozi kwita ku mibereho y'amatungo, aho bishoboka bakirinda gutandukanya inka zimaze igihe zibana, cyane cyane igihe cyo kuzimurira ahandi.
Ibi biri mu rwego rwo guteza imbere imibereho myiza y'inyamaswa, kuko ubushakashatsi bwagaragaje ko ubuzima bwiza bw'amatungo butagira akamaro ku nyamaswa gusa, ahubwo bugira uruhare no mu kongera umusaruro no kugabanya indwara ziterwa na stress.
N'ubwo abantu bakunda kubivuga nk'urwenya ko "inka zigira inshuti magara," ubushakashatsi bwa siyansi bwerekanye ko ibi ari ukuri. Inka zigira izo zikunda kubana na zo kurusha izindi, kandi kuzitandukanya bishobora kuzitera guhangayika no guhindura imyitwarire yazo.
Ibi ni kimwe mu bimenyetso bigaragaza ko inyamaswa na zo zigira amarangamutima n'imibanire igoye kurusha uko abantu benshi babyumva.
Ni na yo mpamvu abahanga bakomeza gushimangira ko kuzitaho no kuziha imibereho myiza bidafasha gusa mu bworozi, ahubwo binubahiriza imibereho y'ibinyabuzima bifite ubushobozi bwo kugirana umubano no kumva ihungabana igihe bitandukanye n'bindi binyabuzima bimenyeranye.