Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB
Difficult calvings and stillbirths are problems in Swedish dairy production that result in large expenses for the farmers and welfare issues concerning the animals. A common opinion is that the live weight of SRB and SLB is increasing, and whether increased weights have caused the increase in calvin...
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| Formato: | Otro |
| Lenguaje: | sueco sueco |
| Publicado: |
2006
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/11088/ |
| _version_ | 1855571805575577600 |
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| author | Sundberg, Therese |
| author_browse | Sundberg, Therese |
| author_facet | Sundberg, Therese |
| author_sort | Sundberg, Therese |
| collection | Epsilon Archive for Student Projects |
| description | Difficult calvings and stillbirths are problems in Swedish dairy production that result in large expenses for the farmers and welfare issues concerning the animals. A common opinion is that the live weight of SRB and SLB is increasing, and whether increased weights have caused the increase in calving problems has been discussed. The aim of this study was to investigate the relationship between the relative birth weight (calf/cow) and calving difficulty and stillbirth, respectively. The importance of breed and parity for the relative weight has been investigated, and comparisons with previous studies have been made to evaluate whether the relative weight has changed over the last decades or not.
The study was based on 807 calvings, registered during the period 1993-2003 in the experimental dairy herd of the Swedish University of Agricultural Sciences (Jälla). During this period a selection experiment was in progress, consisting of two selection lines of SRB with low or high milk fat content at equal and high milk energy production. Because of this, three breeds/selection lines were investigated; SRB-low fat, SRB-high fat and SLB. Cow and calf were individually weighed after the calving and calving performance was assessed based on the extent of assistance required; easy calving (unobserved successful calving or unassisted calving), normal calving (assistance of one or two persons required), difficult calving (assistance of two or more persons required), and very difficult calving (veterinary assistance required). Calves dead at birth or within 24 hours of birth were considered stillborn.
The frequencies of difficult calvings and stillbirths were highest in SLB, 11,2 % and 8,1 % respectively. The proportion of difficult calvings was comparable between the two SRB lines, 3,3 % in the high fat line and 3,0 % in the low fat line. The frequency of stillbirths on the other hand, was twice as high in the high fat line (4,5 %) compared to the low fat line (2,2 %). In general, heifers had more problems at calving than cows.
The results indicate an increase in the live weight of SRB and SLB during the last decades. The weight of the mother at calving has increased more (in per cent) than the birth weight of the calf, resulting in decreased relative weight. The low fat line had slightly lower relative weight (6,5 %) than the high fat line and SLB, and no difference could be shown between the latter two (6,7 %). Bull calves had higher uncorrected relative weight compared to heifer calves, and the difference ranged between 0,46-0,60 percentage points among the three breeds/selectionlines. The relative birth weight had an influence on the viability of the calf, but no effect on calving performance was found.
The cow weight at calving, expressed as a percentage, increased with age most in the low fat line of SRB, followed by SLB and SRB high fat line. Heifers showed the greatest change in weight, and the change decreased gradually in later parities. Higher dam weight appeared to result in increased birth weight of the calf. The increase in birth weights did not, howewer, show the same trend as the dams weights, but were comparable between the breeds/selection lines. The birth weight of calves born by heifers seemed to have increased more than the birth weight of calves born by cows, and the largest increase was found in calves of SRB heifers. The uncorrected mean birth weight was slightly less than 46 kg in the calves of SLB heifers, and in the calves of SRB heifers the corresponding weight was just over 41 kg. The calf birth weight was more than 2 kg higher in later parities. The sex of the calf had a significant effect on birth weight, and bull calves were in general heavier than heifer calves. The difference in birth weight between male and female calves was 4,4 kg in SLB, and 3,2 kg and 2,8 kg in SRB low and high line, respecively. Calving performance and stillbirth were both influenced by the birth weight of the calf. |
| format | Otro |
| id | RepoSLU11088 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish swe |
| publishDate | 2006 |
| publishDateSort | 2006 |
| record_format | eprints |
| spelling | RepoSLU110882017-09-29T08:50:20Z https://stud.epsilon.slu.se/11088/ Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB Sundberg, Therese Animal genetics and breeding Difficult calvings and stillbirths are problems in Swedish dairy production that result in large expenses for the farmers and welfare issues concerning the animals. A common opinion is that the live weight of SRB and SLB is increasing, and whether increased weights have caused the increase in calving problems has been discussed. The aim of this study was to investigate the relationship between the relative birth weight (calf/cow) and calving difficulty and stillbirth, respectively. The importance of breed and parity for the relative weight has been investigated, and comparisons with previous studies have been made to evaluate whether the relative weight has changed over the last decades or not. The study was based on 807 calvings, registered during the period 1993-2003 in the experimental dairy herd of the Swedish University of Agricultural Sciences (Jälla). During this period a selection experiment was in progress, consisting of two selection lines of SRB with low or high milk fat content at equal and high milk energy production. Because of this, three breeds/selection lines were investigated; SRB-low fat, SRB-high fat and SLB. Cow and calf were individually weighed after the calving and calving performance was assessed based on the extent of assistance required; easy calving (unobserved successful calving or unassisted calving), normal calving (assistance of one or two persons required), difficult calving (assistance of two or more persons required), and very difficult calving (veterinary assistance required). Calves dead at birth or within 24 hours of birth were considered stillborn. The frequencies of difficult calvings and stillbirths were highest in SLB, 11,2 % and 8,1 % respectively. The proportion of difficult calvings was comparable between the two SRB lines, 3,3 % in the high fat line and 3,0 % in the low fat line. The frequency of stillbirths on the other hand, was twice as high in the high fat line (4,5 %) compared to the low fat line (2,2 %). In general, heifers had more problems at calving than cows. The results indicate an increase in the live weight of SRB and SLB during the last decades. The weight of the mother at calving has increased more (in per cent) than the birth weight of the calf, resulting in decreased relative weight. The low fat line had slightly lower relative weight (6,5 %) than the high fat line and SLB, and no difference could be shown between the latter two (6,7 %). Bull calves had higher uncorrected relative weight compared to heifer calves, and the difference ranged between 0,46-0,60 percentage points among the three breeds/selectionlines. The relative birth weight had an influence on the viability of the calf, but no effect on calving performance was found. The cow weight at calving, expressed as a percentage, increased with age most in the low fat line of SRB, followed by SLB and SRB high fat line. Heifers showed the greatest change in weight, and the change decreased gradually in later parities. Higher dam weight appeared to result in increased birth weight of the calf. The increase in birth weights did not, howewer, show the same trend as the dams weights, but were comparable between the breeds/selection lines. The birth weight of calves born by heifers seemed to have increased more than the birth weight of calves born by cows, and the largest increase was found in calves of SRB heifers. The uncorrected mean birth weight was slightly less than 46 kg in the calves of SLB heifers, and in the calves of SRB heifers the corresponding weight was just over 41 kg. The calf birth weight was more than 2 kg higher in later parities. The sex of the calf had a significant effect on birth weight, and bull calves were in general heavier than heifer calves. The difference in birth weight between male and female calves was 4,4 kg in SLB, and 3,2 kg and 2,8 kg in SRB low and high line, respecively. Calving performance and stillbirth were both influenced by the birth weight of the calf. Svåra kalvningar och dödfödslar är ett problem inom svensk mjölkproduktion och medför stora kostnader för lantbrukaren samt lidande för djuren. En allmän uppfattning är att SRB och SLB blir allt större men huruvida detta kan vara en orsak till kalvningssvårigheter är oklart. Syftet med detta examensarbete var att studera sambanden mellan den relativa födelsevikten (kalv/ko) och kalvningsförloppet respektive kalvens livskraft. Rasens och kalvningsnumrets betydelse för den relativa vikten har undersökts och jämförelser med tidigare studier har gjorts för att klargöra om den relativa vikten har förändrats de senaste decennierna. Studien baserades på 807 kalvningar som registrerades under perioden 1993-2003 i Institutionen för husdjursgenetiks (SLU) försöksbesättning på Jälla Naturbruksgymnasium. I besättningen pågick under den studerade perioden ett selektionsförsök, där SRB selekterades för låg alternativt hög fetthalt i mjölken vid lika och hög energikoncentration. Detta medförde att tre raser/selektionslinjer studerades; SRB-låg, SRB-hög samt SLB. Vikten hos ko och kalv registrerades i anslutning till kalvningen och kalvningsförloppet bedömdes utifrån moderns behov av assistans; mycket lätt kalvning (oövervakad kalvning med lyckad utgång eller kalvning utan draghjälp), lätt kalvning (draghjälp av en till två personer), svår kalvning (draghjälp av minst två personer) och mycket svår kalvning (veterinäringripande var nödvändigt). En kalv definierades som dödfödd om den avled inom 24 timmar efter kalvningen. Frekvensen av kalvningssvårigheter och dödfödslar var högst hos SLB, 11,2 % respektive 8,1 %. Andelen svåra kalvningar var jämförbar mellan de båda SRB-linjerna, 3,3 % och 3,0 % hos hög- respektive låglinjen. Dödfödselfrekvensen skilde sig däremot och var dubbelt så hög hos SRB-hög (4,5 %) jämfört med SRB-låg (2,2 %). Generellt hade kvigor mer problem i samband med kalvningen än kor. Resultaten från denna studie tyder på att SLB och SRB har blivit tyngre de senaste decennierna. Moderns vikt vid kalvningen har ökat procentuellt mer än kalvarnas födelsevikt vilket medför att den relativa vikten (kalv/ko) har minskat. Låglinjen hade lägre relativ vikt (6,5 %) än höglinjen samt SLB, mellan vilka ingen skillnad kunde påvisas (ca 6,7 %). Tjurkalvarna hade högre okorrigerad relativ vikt än kvigkalvarna och skillnaden mellan könen var 0,46-0,60 procentenheter hos de tre raserna/selektionslinjerna. Den relativa vikten hade effekt på kalvens livskraft men någon inverkan på kalvningsförloppet kunde inte påvisas. Den procentuellt största ökningen av moderns vikt vid kalvning skedde hos låglinjen, följt av SLB och därefter höglinjen. Viktsförändringen var mest markant hos kvigor och minskade successivt med ökande kalvningsnummer. Hög vikt hos modern visade sig medföra högre födelsevikt hos kalven. Kalvarnas viktsökning uppvisade dock inte samma trend som kornas viktsökning utan var likvärdig hos raserna/selektionslinjerna. Kvigornas kalvar hade haft en procentuellt högre viktsökning än de kalvar som föddes av kor, och störst var viktsökningen bland SRB-kvigornas kalvar. Den okorrigerade kalvvikten var strax under 46 kg hos SLBkvigor, och hos SRB-kvigor var motsvarande vikt drygt 41 kg. Kalvvikten vid senare kalvningsnummer var ca 2 kg högre. Kalvens kön hade signifikant effekt på födelsevikten och tjurkalvar vägde generellt mer än kvigkalvar. Hos SLB var skillnaden mellan könen 4,4 kg, och hos SRB linjerna var motsvarande siffror 3,2 kg och 2,8 kg för låg- respektive höglinjen. Kalvens födelsevikt påverkade både kalvningsförloppet och kalvens livskraft. 2006-10-20 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/11088/1/sundberg_t_170929.pdf Sundberg, Therese, 2005. Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB. UNSPECIFIED, Uppsala. Uppsala: (VH) > Dept. of Animal Breeding and Genetics (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-670.html> urn:nbn:se:slu:epsilon-s-7289 swe |
| spellingShingle | Animal genetics and breeding Sundberg, Therese Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title | Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title_full | Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title_fullStr | Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title_full_unstemmed | Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title_short | Den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos SRB och SLB |
| title_sort | den relativa viktens (kalv/ko) inflytande på kalvningsegenskaperna hos srb och slb |
| topic | Animal genetics and breeding |
| url | https://stud.epsilon.slu.se/11088/ https://stud.epsilon.slu.se/11088/ |