The influence of milking procedures on cow’s teat tissue, milk yield and milking time

U radu je istražen utjecaj načina mužnje na promjenu dužine i promjera vrha sise, te količinu i protok mlijeka. Uspoređena su dva načina mužnje. U prvom muzač odlučuje o trenutku skidanja muzne jedinice s vimena krave a u drugom, kada se protok mlijeka smanji ispod 200 g/min, muzna jedinica se sama skida s vimena. Na farmama A i B obavljena su mjerenja 15 slučajno izabranih krava koje nisu pokazivale znakove kliničkog mastitisa. Rezultati pokazuju da između farme A i B ne postoje značajne razlike u dužini sisa i promjera vrha sisa prije i poslije mužnje. Strojna mužnja je na farmi A trajala prosječno 6 min i 58 s, dok je na farmi B trajala 5 min i 3 s. Na farmi B prosječno je namuzeno 12,9 kg mlijeka, a na farmi A 13,4 kg. Trajanje strojne mužnje bilo je kraće na farmi B u odnosu na farmu A. Prosječna količina pomuzenog mlijeka po kravi bila je približno ista na obje farme. Automatsko skidanje muzne jedinice (težine 2 kg), kada protok mlijeka padne ispod 200 g/min smanjuje trajanje mužnje što je dobro za očuvanje zdravlja vimena.The aim of this study was to evaluate the effect of two different milking procedures on teat length and diameter, milk yield and milking time. During the first milking procedure the milker decides when to remove the milking cluster from the udder, while in the second an automatic cluster removal, when milk flow was lower than 200 g/min, was performed. Measurements were made on two commercial farms B and A on 15 randomly chosen cows without any clinical sign of mastitis. There were no significant differences between those farms in teat length and diameter differences before and after the milking. Average milking time on farm A was 6 min and 58 s, while on farm B was 5 min and 3 s. Average milk yield was 12.9 kg on farm B and 13.4 kg on farm A. Milking time was considerably shorter on farm B compared to farm A, while milk yield was almost equal on both farms. Automatic cluster weighting 2 kg removal was performed when milk flow was lower than 200 g/min in order to shorten the time needed to milk the cow, ensuring good udder health

ASSOCIATION OF β-LAKTOGLOBULIN WITH MILK YIELD OF CROATIAN SIMMENTAL II. GENE EFFECT

Istraživanje utjecaj alela β- laktoglobulin lokusa u 195 uzoraka na količinu mlijeka i masti (kg) te sadržaj masti (%) prve laktacije hrvatskog simentalca. Za isti gen lokus procijenjen je udio aditivne u fenotipskoj varijanci. Prosječan efekt supstitucije alela B za A izračunat je gen supstitucijskim modelom. Aditivna genetska varijanca (ơ²ᴀ) istih mliječnih proizvodnih osobina izračunata je formulom ơ²ᴀ =2pqα². Signifikantan prosječan efekt supstitucije alela B za A utvrđen je za količinu mlijeka - 176,648 ± 63,273 (P=0,006), masti - 5,487 ± 2,690 (P=0,043) i sadržaj masti 0,041 ± 0,013 (P = 0,003). Udio aditivne genetske varijance u fonotipskoj varijanci iznosio 4,1% za količinu mlijeka (kg), 2,2% za količinu masti (kg) i 4,9% za sadržaj masti. U ovom radu utvrđena je veća količina mlijeka i masti (kg) za alel A, te viši postotak masti (%) za alel B. Naravno, posebna su daljnja istraživanja koja bi potvrdila dobivene rezultate prije uključivanja β-laktoglobulin alela u selekciju.Effects of β-lactoglobulin locus on first lactation milk yield, kilograms of fat and fat percentage in milk samples from 195 Croatian Simmental cows were examined by gene substitution models after allele A was set to zero. Additive genetic variance due to β-lactoglobulin locus was calculated by formula ơ²ᴀ =2pq α². The substitution of the B allele for the A allele was associated with decreased mitt yield (P=0,006) and fat yield (P=0,043) but increased fat content (P=0,003). The contribution of B- lactoglobulin locus accounted for 4.1% of phenotypic variance in milk yield, 2.2% in fat yield and 4.9% in fat content. This study found that milk with allele A had higher milk and fat yield but allele B was associated with higher fat content. However, more research is necessary to confirm these findings before B- lactoglobulin alelles are included in selection

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements