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Würtz, Mikaela, 2019. Field study of the drought’s impact on feeding strategy and biological parameters in early lactation dairy cattle. Second cycle, A2E. Uppsala: SLU, Dept. of Animal Nutrition and Management

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Abstract

The summer of 2018 was unusually warm and dry. For animal production, this resulted in poor pastures, reduced harvests of crops, such as roughage and grains, and increased risk for heat stress in the animals. The drought led to problems as in shortage of animal feed, which made the feeding of dairy cattle difficult. This field study was performed to research how Swedish dairy farmers handled the drought and feed situation. Eleven farms were visited, and the farmers were asked questions from a questionnaire, regarding whether they experienced that they were affected by the drought and feed situation or not, questions about the feeding strategy on the farm, if alternative feedstuffs were used and if the farmers had been required to sell or slaughter animals because of the feed situation. The farmers had different experiences of the drought where some of them tried feeding alternative feedstuffs as bean straw, peas, whole crop silage, silage from fallow land or a complementing compound feed. Some farmers needed to slaughter or sell animals due to the lack of feed. In total, 59 primiparous cows in their early lactation were included. The examined cows were of the breeds Swedish Holstein (SH), Swedish Red (SRB) and Jersey cattle. In addition to the questionnaire, feed samples were collected from the roughage used, to see if relations could be found between the result of feed samples and other studied parameters. Milk- and blood samples were collected from 3-10 cows from each farm. These cows were also body condition scored. It was studied if a relation could be found between any experienced problems caused by the feed situation, and the studied biological parameters. These parameters were levels of myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0) and oleic acid (C18:1 cis-9) in milk, and levels of b-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), glucose, insulin and insulin-like growth factor 1 (IGF-1) in blood plasma, body conditions and feed samples. The feed samples were analysed for contents of dry matter (DM), metabolizable energy (ME), ash, crude protein (CP) and neutral detergent fibre (NDF). The majority of the examined cows (93%) had body conditions between 3.0 and 4.0 of a scale of 1-5, where 1 is emaciated and 5 is obese. Approximate energy balances on herd level were estimated via the software IndividRAM which showed that the herds were between 92 and 109%. Relations were found between some of the studied parameters, with different parameters identified on the different farms. Statistical analyses showed significant correlations between C14:0 and C18:1 cis-9; NEFA and C18:1 cis-9; BHB and C18:1 cis-9; BHB and C14:0; BHB and glucose; BHB and NEFA. An analysis of variance (ANOVA) showed significant differences between the farms regarding the levels of the milk fatty acids C14:0, C16:0, C18:0, plasma components BHB, NEFA, glucose, IGF-1 and body conditions.

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Sommaren 2018 var ovanligt varm och torr. Detta resulterade bl.a. i försämrade beten, minskade skördar av grödor, såsom grovfoder och spannmål. Torkan orsakade problem som exempelvis djurfoderbrist, vilket försvårade utfodringen av mjölkkor. Denna fältstudie gick ut på att undersöka hur svenska mjölkbönder hanterat torkan och fodersituationen. Elva gårdar besöktes och lantbrukarna fick frågor från en frågeenkät som handlade om huruvida de påverkades av torkan och fodersituationen eller inte, frågor om utfodringsstrategin på gården, om alternativa fodermedel använts och om lantbrukarna behövt sälja eller slakta djur till följd av fodersituationen. Lantbrukarna hade olika upplevelser av torkan, där en del testade att utfodra alternativa fodermedel som bönhalm, ärter, helsädesensilage, ensilage från trädad mark eller ett kompletterande pelleterat foder. En del av lantbrukarna behövde slakta eller sälja djur till följd av fodersituationen. Totalt ingick 59 kor som var i tidig laktation och nyligen fått sin första kalv. De kor som undersöktes var av raserna Svensk Holstein (SH), Svensk rödbrokig boskap (SRB) och Jersey-boskap. Utöver frågeenkäten togs foderprov från det grovfoder som användes för att se om samband fanns mellan foderprovsanalysen och andra studerade parametrar. Mjölk- och blodprover togs från 3-10 kor från varje gård. Dessa kor hullbedömdes även. Det undersöktes om samband kunde finnas mellan eventuella upplevda problem på grund av fodersituationen, och de studerade biologiska parametrarna. Dessa parametrar var koncentrationer av myristinsyra (C14:0), palmitinsyra (C16:0), stearinsyra (C18:0) och oljesyra (C18:1 cis-9) i mjölk, och koncentrationer av blodplasmakomponenterna b-hydroxybutyrat (BHB), icke-esterifierade fettsyror (NEFA), glukos, insulin och insulinliknande tillväxtfaktor (IGF-1), hull och foderprover. De grovfoderprover som togs analyserades för torrsubstans, innehåll av smältbar energi (ME), aska, råprotein (CP) och fiber (NDF). Majoriteten av de undersökta korna (93%) hade hull mellan 3,0 och 4,0 på en skala från 1-5, där 1 är undernärd och 5 är överviktig. Ungefärliga energibalanser på besättningsnivå uppskattades med datorprogrammet IndividRAM som visade att besättningarna var mellan 92 och 109%. Samband fanns mellan en del parametrar. Vilka parametrar som hade ett samband varierade mellan gårdarna. Statistiska analyser visade signifikanta korrelationer mellan C14:0 och C18:1 cis-9; NEFA och C18:1 cis-9; BHB och C18:1 cis-9; BHB och C14:0; BHB och glukos; BHB och NEFA. En variansanalys (ANOVA) visade signifikanta skillnader mellan gårdarna gällande koncentrationer av mjölkfettsyrorna C14:0, C16:0, C18:0, plasmakomponenterna BHB, NEFA, glukos, IGF-1 och hull.

Main title:Field study of the drought’s impact on feeding strategy and biological parameters in early lactation dairy cattle
Authors:Würtz, Mikaela
Supervisor:Edvardsson Rasmussen, Anna and Holtenius, Kjell
Examiner:Agenäs, Sigrid
Series:UNSPECIFIED
Volume/Sequential designation:UNSPECIFIED
Year of Publication:2019
Level and depth descriptor:Second cycle, A2E
Student's programme affiliation:VY001 Agricultural Science Programme - Animal Science 270 HEC
Supervising department:(VH) > Dept. of Animal Nutrition and Management
Keywords:dairy cattle, drought, energy balance, feeding, metabolism
URN:NBN:urn:nbn:se:slu:epsilon-s-10509
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-10509
Subjects:Animal husbandry
Language:English
Deposited On:04 Jun 2019 10:13
Metadata Last Modified:05 Jun 2019 01:00

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