The　cognitive　radio　enabled　cooperative　communication　is　envisioned　to　be　a　vital　part　of　the　5G-based　Internet　of　Things　(IoT).　Since　IoT　contains　billions　of　resource　constrained　devices,　spectrum　utilization　efficiency　(SUE)　becomes　a　significant　problem　in　order　to　accommodate　such　a　large　number　of　devices　within　the　scarce　spectrum.　Therefore,　in　this　paper,　SUE　of　cognitive　radio　networks　(CRNs)　is　investigated　in　terms　of　channel　availability　and　service　completion　probability.　We　propose　a　spectrum　efficient　CRN　(SE-CRN)　that　employs　a　hybrid　underlay-interweave　(UI)　mode　of　CRNs　for　secondary　users　(SUs)　under　cooperative　communication.　Two　types　of　SUs,　with　low　and　high　priority　levels,　are　considered.　Moreover,　a　multi-attribute　based　approach　for　service　determination　for　low　priority　users＇　interruption　is　proposed　that　ensures　the　optimal　channel　availability　for　high　priority　users.　SE-CRN　is　composed　of　two　algorithms,　namely,　spectrum　efficient　dynamic　spectrum　access　(SE-DSA)　and　spectrum　efficient　dynamic　channel　reservation　(SE-DCR).　SE-DSA　dynamically　assigns　available　channels　to　primary　and　secondary　users　based　on　their　priority　levels.　SE-DCR　dynamically　keeps　a　number　of　channels　reserved　to　support　interruption　of　ongoing　services.　We　utilize　continuous　time　Markov　chain　(CTMC)　for　modeling　and　also　form　mathematical　expressions　for　a　number　of　QoS　parameters.　The　scheme　is　evaluated　under　varying　levels　of　network　traffic　loads　and　multiple　rates　of　channel　failure.　We　show　through　numerical　results　that　SUE　can　be　reasonably　enhanced　by　SE-CRN.