Skirtingų veislių karvių melžimo savybių palyginimas
Lembertas, Klaudijus |
Šlyžius, Evaldas |
Šimkienė, Aldona | |
Šio darbo tikslas - palyginti skirtingų veislių karvių melžimo savybes. Darbo uždaviniai. 1. Išanalizuoti Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių melžimo savybes. 2. Nustatyti laktacijos įtaką karvių melžimo savybėms. 3. Nustatyti melžimo laiko įtaką tiriamų veislių karvių pieno kiekiui ir vidutiniam pieno atidavimo greičiui. 4. Įvertinti ūkio įtaką melžimo savybėms. 5. Atlikti somatinių ląstelių skaičiaus (SLS) ir melžimo savybių koreliacinę analizę. Išvados: 1) Išanalizavus tirtų Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių pagrindinių melžimo savybių rezultatus nustatyta, kad: 1.1. Vidutinis pieno tekėjimo greitis Lietuvos žalųjų (0,02 kg/min) buvo didesnis nei Lietuvos juodmargių veislės karvių (p<0,05). 1.2. Didžiausia pieno tekėjimo srovė buvo Lietuvos juodmargių buvo 0,05 kg/min didesnė nei Lietuvos žalųjų (p>0,05). 1.3. Melžimo laikas 0,11 min. buvo ilgesnis Lietuvos žalųjų veislės karvių. 2) Atlikus skirtingų laktacijų karvių produktyvumo ir melžimo savybių analizę, nustatyta, kad I laktacijos karvių bendras pieno kiekis (kg) ir vidutinis pieno atidavimo greitis (kg/min). buvo didžiausias Lietuvos žalųjų karvių, tačiau I laktacijos karvių melžimo trukmė buvo ilgesnė nei Lietuvos juodmargių veislės karvių. 3) Nustatyta, kad Lietuvos juodmargių, kurios melžėsi ilgiau nei 6 minutes buvo 4,73% daugiau nei Lietuvos žalųjų veislių karvių (p<0,05) Iš pateiktų duomenų matome, kad Lietuvos žalųjų buvo beveik 5% daugiau nei Lietuvos juodmargių, kurios melžėsi trumpiau nei 6 minutes (p<0,05). 4) Atlikus ūkio analizę pagal melžimo savybes, ūkyje A nustatytas 0,15 kg/min. didesnis vidutinis pieno tekėjimo greitis ir 0,12 kg/min didesnė pieno tekėjimo srovė nei ūkyje B. Melžimo laikas 0,3 min. nustatytas trumpesnė B ūkyje palyginus su ūkiu A. 5) Nustatyta teigiama statistiškai patikima koreliacija tarp primelžto pieno kiekio ir vidutinio pieno tekėjimo greičio (r=0,647, p<0,01) bei primelžto pieno kiekio ir melžimo trukmės (r=0,532, p<0,01).
The aim of this thesis was to assess milking properties of cows of different breeds. Objectives of the paper: 1. Analyze the Lithuanian Black and White and Lithuanian Red cows milking qualities. 2. Determine lactation influence milking performance. 3. Determine the time of milking cows tested influence on milk yield and milk the average speed of the output. 4. To evaluate the farm impact of the milking properties. 5. Perform somatic cell count and milking performance correlation analysis. The scientific research was carried out between 2012-2014 at the Department of Animal Breeding of the Veterinary Academy of the Lithuanian University of Health Sciences and 2 dairy farms. Descriptive statistics: the average of investigated traits (M), standard errors were calculated using the EXEL and “R” (The R Project for Statistical Computing, 2012) statistical packages Milking properties were analyzed with the help of the device Lactocorder. In total 81 cows of Lithuanian black and white and Lithuanian red cattle breeds from two farms were analyzed. Lithuanian black and white cows constituted 71.6 percent, while Lithuanian red cows constituted 28.4 percent. According to lactation all analyzed cows were divided into the following three groups: lactation I, lactation II, lactation III and later. The first lactation cows constituted 6.1 % , the second lactation cows constituted 19.75 % and the group of cows of the third and later lactation was the largest and constituted 74.07 % . The research showed that the average milk yield of Lithuanian black and white cows was 7.7 kg, the average milk flow rate was 1.38 kg/min and the maximum milk flow rate was 2.30 kg/min. It was also determined that the average milk yield of Lithuanian red cows was 8.99 kg, the maximum milk flow rate was 2.25 kg/min and the average milk flow rate was 1.58 kg/min. The comparison of the main milking properties – average milk yield and average milk flow rate – determined during the research showed that Lithuanian red cows are more productive than Lithuanian black and white cows. The average milk yield (kg) differed by 1.29 kg, while the average milk flow rate differed by 0.2 kg/min. The milk yield of Lithuanian red cows was higher by 14.35 percent in average compared to Lithuanian black and white cows. The maximum milk flow rates were very similar: 2.3 kg/min and 2.25 kg/min in case of Lithuanian black and white cows and Lithuanian red cows respectively (p>0.05). The difference was very insignificant – 2.17 percent. The difference between milking durations was insignificant as well. Lithuanian black and white cows were milked by 0.11 min (1.9 percent) faster than Lithuanian red cows. When the milking duration was divided into two categories, one being up to 6 min and the other – more than 6 min, it was found that Lithuanian red cows that fell under the category of up to 6 min produced more milk than Lithuanian black and white cows, i.e. by 1.76 kg more. Lithuanian red cows that fell under the category of ≥6 min also produced more milk, i.e. by 0.71 kg more (p>0.05). The research showed that Lithuanian red cows of the first lactation and Lithuanian black and white cows of the third and later lactation produce the largest milk yields, i.e. 10.12 kg and 8.09 kg respectively. Their average milking durations did not exceed the limit of 6 minutes: Lithuanian black and white cows were milked 5.56 min, whereas Lithuanian red cows – 5.76 min. The comparison of the most productive lactations of both breeds revealed that Lithuanian red cows produced 2.03 kg more milk than Lithuanian black and white cows, the difference being as high as 20.06 percent. It was observed that cows kept on the farm “A” were more productive in respect of all measured indicators compared to the farm “B”. The average milk yield produced by cows kept on the farm “A” (n=8) was higher by 1.7 kg (16.8 percent) compared to cows kept on the farm “B” (n=73). The average milk flow rate differed by 0.2 kg/min (9.25 percent) and was higher on the farm “A”. The maximum milk flow differed by 0.12 kg/min. The milking duration was shorter in the farm “B” by 4.94 percent. Somatic cell count was grouped according to the lactations and was the lowest in the second lactation both in case of Lithuanian black and white cows (36 thousand/ml) and Lithuanian red cows (39 thousand/ml). Somatic cell count in milk of the Ist lactation Lithuanian red cows was higher by 17.65 percent (p<0.05) compared to Lithuanian black and white cows. The highest somatic cell count was found in milk of Lithuanian red cows of the IIIrd and later lactation and it was higher by 42.4 percent compared to the lowest somatic cell count in milk of Lithuanian black and white cows of the IInd lactation and by 18.4 percent (p<0.05) higher compared to Lithuanian black and white cows of the IIIrd and later lactation. On the farm “A” the total amount of cows in whose milk somatic cell count was up to 200 thousand/ml constituted 87.5 percent, whereas on the farm “B” – 90.41 percent. On the farm “A” the total amount of cows in whose milk somatic cell count was from 200 thousand/ml to 400 thousand/ml constituted 12.5 percent, whereas on the farm “B” – 8.22 percent. Somatic cell count in milk exceeding 400 thousand/ml was found only on the farm “B” and constituted only 1.37 percent of all analyzed cows (p<0.05). Correlation analysis showed a statistically significant positive correlation between milk yield and milking duration (r = 0.532, p<0.01), even higher correlation was found between milk yield and average milk flow rate (r = 0.647, p <0.01).