Zvonimir Prpić

Effect of breed on mineral composition of meat from light lambs

Abstract The proximate composition and mineral content of light lambs muscle (derived from Istrian and Dalmatian Pramenka breeds) were studied. The M. Longissimus dorsi (MLD) samples of 30 carcasses were analysed and the effects of breed and sex were studied. Although lambs of investigated breeds were similar for slaughter age (2.5 months), Dalmatian Pramenka had significantly higher carcass weights (CW; P<0.05). Breed had a significant influence on moisture and fat contents, whilst mineral composition (with the exception of selenium) was scarcely affected by breed and sex. Fat and moisture contents were significantly correlated with cold CW. The magnesium, calcium, manganese and selenium contents were significantly correlated (r=0.50, -0.46, 0.44, 0.54; P<0.05 respectively) with CW. This study contributes to characterization of lamb carcasses from Istrian Sheep and Dalmatian Pramenka breeds and provides new data on the composition of the MLD of light lambs.

Relationship of litter size with milk yield, udder morphology and udder health of East Friesian sheep

The aim of this study was to determine relationship between litter size and milk yield, udder morphology, and udder health of East Friesian ewes. For that purpose a total of 80 East Friesian ewes, from 2nd to 4th lactation, with symmetrical udders, without visible (clinical) signs of mastitis were involved in this study. Until weaning at average age of 60±5 days lambs suckled their mothers exclusively. During milking period regular milking controls (on a monthly basis) were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis were taken. Three times per lactation (1st, 3rd and 5th milking control), prior to the milking, evaluation and measuring of udder morphology traits were performed. Also, during above-mentioned test-day controls (three times per lactation) one sample of half udder milk was taken with purpose of bacterial and somatic cell counts (SCC) tests. Ewes with twin and triplet lambs had significantly (P 0.05) and depth (P>0.05). Besides that,udders of ewes with twins and triplets had higher cistern, greater teat angle and larger teat dimensions than ewes with singles, although those differences were not statistically significant. Ewes with single lamb had teats more (P<0.05) cranially oriented than ewes with twins and triplets. Significant (P<0.05) differences in somatic cell count (log10SCC) between ewes of different litter sizes were determined, regardless of the health status of mammary gland. The higher (P<0.05) prevalence of subclinical mastitis was observed in ewes with twin and triplet lambs than in ewes with singles. In 46% of mammary glands (udder halves) of sheep with twins and triplets a subclinical mastitis was established and even 65.8% of them undergone an infection of one or both halves of the udder during the milking period.

Some dairy traits of Istrian ewes kept in semi-intensive farming conditions

Istrian sheep has the highest milk yield among indigenous Croatian sheep breeds though originally belongs to a group of sheep of combined production traits. Since milk of Istrian sheep is traditionally processed into cheese and that processing possibilities of milk, among other things, are defined by its chemical composition and hygienic quality, the aim of this study was to determine the influence of some environmental factors (year, parity, stage of lactation, season (month) of lambing) on daily and lactation milk yield, lactation length, milk chemical composition and the somatic cell count (SCC) in the milk of Istrian ewes. A total of 83 purebred, dairy Istrian sheep, during three consecutive lactations (from 2012 to 2014), were involved in this research. Due to conditions of feeding, care and housing, all ewes were kept in identical (semi-intensive) farming conditions throughout the whole study period. During milking period of lactation regular milking controls were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis and determination of somatic cell count were taken. During average lactation length of 206 days Istrian ewes produced on average 190.77 kg of milk, or 1.1 kg of milk per day. Milk of Istrian ewes on average contained 6.81% fat, 5.90% protein, 4.32% lactose, 18.08% total solids and 11.31% non-fat solids. The geometric mean of SCC was 316*103*mL-1 of milk (log 5.50±0.02). A significant (P < 0.001) effect of the year is determined on the milk yield and the lactation length, as well as the chemical composition of milk (with the exception of protein) and SCC. Ewes in the fourth lactation achieved the highest average daily (P < 0.001) and lactation milk yield (P < 0.05), while the first-lambing ewes produced milk with the highest content of total solids, milk fat and proteins. Stage of lactation significantly (P < 0.001) affected the daily milk yield, milk chemical composition, as well as the somatic cell count in ewe’s milk. Ewes born in December produced significantly (P < 0.001) more milk than ewes born in January and February. There was a negative correlation between SCC (log10) and daily milk yield (P < 0.001), while the SCC (log10) was positively correlated (P < 0.001) with the contents of total solids, milk fat and proteins.

Influence of the rennet type on the quality of Pag Island cheese (Croatian: Paški sir).

Cilj istraživanja bio je utvrditi utjecaj vrste sirila na fizikalno-kemijske parametre i senzornu kvalitetu i randman paskog sira, proizvedenog s domacim (tradicionalnim) i komercijalnim sirilom. Paski sirevi proizvedeni su s domacim sirilom, ekstrakcijom enzima iz janjeceg sirista (abomasum), i s komercijalnim sirilom u prahu talijanskog proizvođaca „Gruppo Clerici-Sacco“. Ukupno je proizvedeno 7 sarži sira, po dva sira unutar svake sarže. Tijekom 120 dana zrenja, sirevi su periodicno uzorkovani 0., 45., 90. i 120. dana, u svrhu određivanja sadržaja suhe tvari, mlijecne masti, proteina, koncentracije soli te pH vrijednosti sira. Također određen je udio ukupnih slobodnih aminokiselina iz vodenih ekstrakata sira te je provedena analiza proteina i polipeptida gel-elektroforezom u poliakrilamidnom gelu (UREA-PAGE). Istraživanjem nije utvrđen znacajan (P>0, 05) utjecaj vrste ispitivanog sirila na istraživane parametre kvalitete sira te na randman. Predmetnim istraživanjem nije utvrđen statisticki znacajan utjecaj na ispitivane fizikalno-kemijske parametre, randman te senzornu kvalitetu paskog sira, ali su dobiveni rezultati pokazali prakticne razlike koje bi mogle imati važnost u primjeni, pogotovo u postizanju boljeg randmana i vece brzine zrenja.