The aim of this diploma thesis is to evaluate fertility indicators and milk production on a selected farm. I have anticipated lower milk utility and less frequent pregnancy rate during summer time in comparison to other seasons.
The selected stable in Bílý Újezd is a part of ZEAS Podorlicko a.s. corporation. In this stable the dairy cattle of Holstein breed was studied. The breed was mixed with ayshir and red holstein, not exceeding 15% of blood mixture. Milk utility of 511 milkers was evaluated from October 1, 2013 to October 31, 2015. The data was gained from Milk Profi Data program and then statistically evaluated in SAS version 9.3. The analysis focused on the influence of lactation sequence, year influence, season influence and the influence of lactation period on daily milk production, percentage ingredient volume and the amount of somatic cells in milk.
The average count of lactations in a herd was 2.34 in the examined period and the average day of lactation was 169.32. A positive influence of lactation sequence on daily milk production was discovered (r = 0.056; P < 0.001). The highest daily milk production was detected within fourth lactation milkers (30.72 kg). Daily milk production was increasing year-on-year, the highest was in 2015 (32.09 kg). The influence of seasons on daily milk production was noticeable. Milkers had statistically the highest volumes of milk production in autumn (30.32 kg; P < 0.001). The lactation period had a negative influence on daily milk production (r = -0.548; P < 0.001). Till 60th day of lactation the daily volume of milk production was increasing, and then since 61st day till the end of lactation it was decreasing. The days of lactation had positive influence on fat content (r = 0.078; P < 0.001).
The influence of lactation sequence on a fat percentage could not be statistically proven. In 2013 the fat content was higher (3.84%) then in 2014 (3.64%). Compared to 2014, the fat content increased on 3.80% in 2015. The lowest fat content in milk was during summer (3.58%). In autumn the fat content reached 3.79% and it was the highest in winter (3.92%). The fat content decreased in spring, falling to 3.75%. A positive influence of lactation period on fat content was proven (r = 0.078; P < 0.001).
Any influence of lactation sequence on protein content was not statistically proven. The highest protein content was noted in 2013 (3.58%), then it decreased in 2014 on 3.52% and 3.48% in 2015. The highest protein content was reached in winter (3.62%). The protein content decresed in spring on 3.51% and the lowest level was in summer (3.38%). The protein content increased again in autumn reaching 3.60%. The influence of season was proven to be positive on lactation period and protein content (r = 0.451; P < 0.001).
A negative influence of lactation sequence on a lactose content was proven (r = -0.375 ; P < 0,001). A positive infuence in lactose content (r = 0.283; P < 0.001) was discovered throught seasons. The lowest lactose content was measured in winter (4.74%), it rose in spring reaching to 4.79% and in summer to 4.80%. The highest lactose content was in autumn (4.84%). Also a negative influcence of lactation period on lactose content was proven (r = -0.221; P < 0.001).
A positive influence of lactation sequence on the amount of somatic cells in ths/mL (r = 0.197; P < 0.001) was discovered. On the contrary the seasons had negative influence on the amount of somatic cells in ths/mL (r = -0.060; P < 0.001). A statistically noticeable difference was revealed between the amount of somatic cells measured in autumn (807.92 ths/mL) and in winter (968.58 ths/mL). The influence of lactation period on the amount of somatic cells was not proven.
Altogether 544 milkers were assesed for reproduction capability in the period from October 1, 2012 to October 31, 2015. The data was obtained from WebSkot program and statistically evaluated by SAS program version 9.3. The analysis focused on the influence of lactation sequence, insemination sequence and the month of insemination pregnancy rates, servis period and the interval of insemination.
The influence of lactation and the insemination sequence on pregnancy rate could not be proven. The analysis showed that the pregnancy rate was lower in August (23.69%) than in December (46.50%).
The influence of insemination on servis period could not be proven. A positive influence of insemination sequence on servis period was discovered (r = 0.802; P < 0.001). The influence of the month of the insemination on servis period was not proven as well.
The influence of lactation sequence nor insemination sequence on insemination interval was not proven. It was discovered that the insemination interval was shorter in December (70.01 days) then in July (90.15 days; P < 0.005).
Hypothesis, which presupposed lower milk utility in summer in comarison to winter was disproved. Hypothesis about lower pregnacy rates in summer months was proved.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:256930 |
| Date | January 2016 |
| Creators | Novotná, Markéta |
| Contributors | Toušová, Renata, Jan, Jan |
| Publisher | Česká zemědělská univerzita v Praze |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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