New insights into body condition score and its association with fatty liver in Holstein dairy cows

Abstract

The aim of this study was to estimate the association between body condition and fatty liver in high-yielding dairy cows. One hundred dry Holstein cows were selected. Cows were scored once for body condition during the dry period, puerperium and month 2 of lactation, according to the system provided by Elanco Animal Health Buletin Al 8478. Body condition loss was determined as marked if loss was over 0.7 points between two consecutive phases of cycles and over 1.5 points between puerperium and month 2 of lactation. Liver tissue samples were taken 12 d after calving and tested for lipid content. 50% of cows had mild (3.92 ± 3.33% fat), 33% moderate (19.28 ± 5.18% fat), and 17% severe fatty liver (36.21 ± 4.55% fat). The mean body condition scores were 3.79 ± 0.55 (dry period), 3.18 ± 0.34 (puerperium) and 2.90 ± 0.29 (month 2 of lactation). Marked body condition loss from the dry period to puerperium had 38% of cows, 20% from dry period to month 2 of lactation and 8% from puerperium to month 2 of lactation. Body condition scores out of the physiological range had 39% dry cows, 49 % cows in puerperium and 9% cows at month 2 of lactation. After dividing cows into groups according to fatty liver degree, it was shown that only cows with severe fatty liver were obese during the dry period and that 76.47% of cows from this group had marked condition loss from the dry period to puerperium, 47.06% from dry period to month 2 of lactation and 23.53% from puerperium to month 2 of lactation. These indicate that in cows with severe fatty liver lipomobilisation is intensive and starts around calving, before milk production enhacement. Our results indicate a strong association between body condition and fatty liver in cows, which can be estimated only when body condition is analyzed in details. Besides, our results clearly indicate that body condition is not the only etiological factor that leads to fatty liver in dairy cows.

Cilj istraživanja u ovom radu je bio da se ispita povezanost telesne kondicije i zamašćenja jetre kod visoko-mlečnih krava. Za ogled je izabrano 100 krava holštajn rase u zasušenju. Telesna kondicija je ocenjena jedanput u zasušenju, puerperijumu i 2. mesecu laktacije prema sistemu Elanco Animal Health Buletin Al 8478. Gubitak u telesnoj kondiciji je označen prekomernim ako je iznosio preko 0,7 poena između dve uzastopne faze ciklusa, odnosno preko 1,5 poena između zasušenja i 2. meseca laktacije. Uzorci jetre su uzeti 12 dana nakon teljenja i ispitani na sadržaj masti. Polovina (50%) krava je imalo blag (3,92±3,33% masti), 33% srednji (19,28±5,18% masti), a 17% krava visok stepen zamašćenja jetre (36,21±4,55% masti). Prosečne OTK krava su iznosile 3,79±0,55 (zasušenje), 3,18±0,34 (puerperijum) i 2,90±0,29 (2. mesec laktacije). Prekomeran gubitak u telesnoj kondiciji između zasušenja i puerperijuma je imalo 38% krava, 20% između zasušenja i 2. meseca laktacije i 8% između puerperijuma i 2. meseca laktacije. Telesnu kondiciju izvan fizioloških granica je imalo 39% krava u zasušenju, 49% krava u puerperijumu i 9% krava u 2. mesecu laktacije. Kada su krave podeljene na osnovu stepena zamašćenja jetre, utvrđeno je da su samo krave sa visokim stepenom zamašćenja jetre bile pregojene u zasušenju, kao i da je kod ove grupe krava u 76,47% slučajeva nastao prekomeran gubitak u telesnoj kondiciji od zasušenja do puerperijuma, u 47,06% od zasušenja do 2. od meseca laktacije i u 23,53% od puerperijuma do 2. meseca laktacije što ukazuje da pojačana lipomobilizacija kod ove grupe krava počinje u periodu oko teljenja vrlo rano, pre nego što nastane značajan porast u proizvodnji mleka. Naši rezultati ukazuju na postojanje značajne povezanosti telesne kodnicije i zamašćenja jetre koja se može utvrditi jedino detaljnom analizom telesne kondicije krava u zapatu. Pored toga, rezultati jasno ukazuju da telesna kondicija nije jedini etiološki faktor u nastanku masne jetre kod krava.