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1.
Measuring heart rate of cows in milking parlour
Marjan Janžekovič, 2005, izvirni znanstveni članek

Ključne besede: heart rate, dairy cows, milking parlour, Polar monitors
Objavljeno: 10.07.2015; Ogledov: 561; Prenosov: 21
URL Povezava na celotno besedilo

2.
Comparison of longevity and production traits of Holstein and Simmental cows of different origin in Slovenia
Marjan Janžekovič, Marko Ocepek, Tadej Virk, Dejan Škorjanc, 2009, izvirni znanstveni članek

Opis: The aim of this research was to establish whether there are differences in the longevity and production characteristics within the studied breeds of cows of different origin. Holstein cows of Slovenian (461) and foreign (356) origin and Simmental cows of Slovenian (261) and foreign (43) origin were studied. Only culled animals that previously had between 1 and 9 lactations were included. The analyzed properties consisted of characteristics related to the longevity and lifetime productivity. Compared with Slovenian cows, imported Holstein cows had a significantly longer calving interval (1210±31 days, 1337±39 days, P=0.008), a longer dry period (172±6 days, 192±7 days, P=0.022), and a significantly lower daily milk yield (23.0±0.2 kg, 22.0±0.3 kg, P=0.002). Significant differences between Simmental cows of Slovenian and foreign origin were observed in functional productivity (1317±52 days, 1808±186 days, P=0.006), longevity (2175±53 days, 2701±145 days, P=0.004), and duration of lifetime lactation (990±38 days, 1265±137 days, P=0.037).
Ključne besede: cows, Holstein breed, Simmental breed, production properties, longevity
Objavljeno: 10.07.2017; Ogledov: 253; Prenosov: 58
.pdf Celotno besedilo (269,31 KB)
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3.
Effect of concentrate exchange on dairy farm
Marjan Janžekovič, Milan Repič, 2009, izvirni znanstveni članek

Opis: The purpose of the research was to establish the effect of concentrates A (C-A) and B (C-B) on the quantity and composition of the produced milk of dairy cows. The research included cows of Holstein Friesian and Simmental breeds and crossbreeds with Simmental breed. The test took place in two periods. The first period with the C-A lasted from December 2004 to February 2005 and included 113 cows. During the second period the C-B was fed. The test endured from April to June 2005. The results of monthly controls of milk quantity and protein and fat contents were entered into the Excel programme and processed with the statistical programme SPSS for Windows 12.0. When the concentrate B was fed, the milk quantity amounted to 21.99 L/day and was statistically significantly (P<0.05) greater than the milk quantity in case of feeding the concentrate A, when the milk quantity was 19.12 L/day. No statistically significant differences (P<0.05) of the protein and fat content in the milk were established.
Ključne besede: milking cows, concentrate, milk quantity, proteins, fats
Objavljeno: 10.07.2017; Ogledov: 238; Prenosov: 49
.pdf Celotno besedilo (275,28 KB)
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4.
The milk quality and feasibility analysis of loose housing dairy cows
Marjan Janžekovič, Črtomir Rozman, 2006, izvirni znanstveni članek

Opis: The aim of the study was technological and economical analysis of free range cow breeding. The case study analyzed two different systems of holstein-fresian dairy cows breeding. The model total costs enterprise budget was developed for evaluation of economic feasibility of loose housing dairy cows in comparison with tied cow breeding system. Computer supported calculation enabled estimation of the most important economical parameters (net return, observed input parameters) loose housing system is economically feasible, if there is a minimum of 41 dairy cows with an average milk production of 8610 kg per cow. It was also established that cows need approximately 6 months to fully adapt to the loose hausing system.
Ključne besede: loose housing, dairy cows, milk quality, coefficient of economy
Objavljeno: 10.07.2017; Ogledov: 377; Prenosov: 60
.pdf Celotno besedilo (221,55 KB)
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5.
Prediction of standard lactation curves for primiparous Holstein cows by using corrected regression models
Janez Jeretina, Drago Babnik, Dejan Škorjanc, 2015, izvirni znanstveni članek

Opis: Prediction of the expected milk yield is important for the management of the primiparous cows (PPC) with a few or no data on their own milk productivity. We developed a system of regression equations for predicting milk yields in standard lactation. The models include the systematic effects of the calving season, the five-year rolling herd average of milk yield of PPC, the breeding values of the parents for milk production, and daily milk recordings. A total of 21,901 lactations of Holstein PPC were collected during the regular monthly milk recordings of cows in the Republic of Slovenia. By including daily milk recordings in the model, the coefficients of determination of regression models for the prediction of milk yield increase: without known recordings (M0) R 2 =0.80; with one recording (M1) R 2 =0.82; with two first consecutive recordings (M2) R 2 =0.86; and with three recordings (M3) R 2 =0.89. Deviations of milk yield up to 500 kg in a standard lactation (<1.6 kg/day) were as follows: with the model M0, they occurred in 53.4% of PPC; with M1, they occurred in 56.3% of PPC; with M2, they occurred in 64.5% of PPC; and with M3, they occurred in 70.9% of PPC. We concluded that the developed system of regression models is an appropriate method for milk yield prediction of PPC.
Ključne besede: primiparous cows, milk yield, prediction, lactation curves, regression equations
Objavljeno: 24.07.2017; Ogledov: 443; Prenosov: 202
.pdf Celotno besedilo (497,85 KB)
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6.
A new somatic cell count index to more accurately predict milk yield losses
Janez Jeretina, Dejan Škorjanc, Drago Babnik, 2017, izvirni znanstveni članek

Opis: Intramammary infection and clinical mastitis in dairy cows leads to considerable economic losses for farmers. The somatic cell concentration in cow's milk has been shown to be an excellent indicator for the prevalence of subclinical mastitis. In this study, a new somatic cell count index (SCCI) was proposed for the accurate prediction of milk yield losses caused by elevated somatic cell count (SCC). In all, 97238 lactations (55207 Holstein cows) from 2328 herds were recorded between 2010 and 2014 under different scenarios (high and low levels of SCC, four lactation stages, different milk yield intensities, and parities (1, 2, and _>3). The standard shape of the curve for SCC was determined using completed standard lactations of healthy cows. The SCCI was defined as the sum of the differences between the measured interpolated values of the natural logarithm of SCC (ln(SCC)) and the values for the standard shape of the curve for SCC for a particular period, divided by the total area enclosed by the standard curve and upper limit of ln(SCC)=10 for SCC. The phenotypic potential of milk yield (305-day milk yield - MY305) was calculated using regression coefficients estimated from the linear regression model for parity and breeding values of cows for milk yield. The extent of daily milk yield loss caused by increased SCC was found to be mainly related to the early stage of lactation. Depending on the possible scenarios, the estimated milk yield loss from MY305 for primiparous cows was at least 0.8 to 0.9 kg day -1 and for multiparous cows it ranged from 1.3 to 4.3 kg day-1. Thus, the SCCI was a suitable indicator for estimating daily milk yield losses associated with increased SCC and might provide farmers reliable information to take appropriate measures for ensuring good health of cows and reducing milk yield losses at the herd level.
Ključne besede: dairy cows, milk production, lactation intervals, milk yield losses, somatic cell count index
Objavljeno: 24.10.2017; Ogledov: 554; Prenosov: 311
.pdf Celotno besedilo (317,33 KB)
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