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50 Uppsatser om Age of first calving - Sida 1 av 4

Orsaker till kalvningssvårigheter och dödfödslar hos SLB och SRB

Difficult calvings and stillborn calves are costly for the producer and lowering these frequencies can decrease the costs for the dairy operation. Each calving in the herd is registered by the farmer and stored in a central database. The information is used to monitor the level of calving-difficulties and stillborn calves in the herd and nationally. Monitoring of these registrations is important to detect possible changes. Breeding-value prediction for calving traits is based on the calving information in the database.

Optimal inkalvningsålder för rekryteringskvigor till mjölkproduktion : relaterat till data ifrån egen besättning

Heifer?s growth may be divided into three main phases: calf period, puberty and pregnancy. When the heifers are about three months old a critical period begins. This period ends when the heifer reach puberty and have her first oestrus at around 9-12 months of age. In the critical period the mammary gland starts to grow at a fast rate and Insulin-like growth factor-1 (IGF-1) transport the growth signals to the mammary glands.

Prövning av liggtidssensorer som indikator på förestående kalvning hos dikor

The aim of the study was to find repetitive behavioral patterns pre calving that could be used as indications of calving in beef cattle. In the study sixteen Standing- and lying down sensors were attached to the leg of sixteen beef cows. Ten of the sixteen beef cows gave birth to calves during the trial period. From these ten cows, data from six cows were used to assess the sensors fitness for use as calving indicators. The analytical part of the experiment was divided into two parts, calculation of divergence of mean lying time within different time intervals, and the number of lying bouts.The first part consisted of optimization of an equation used to highlight divergence in mean lying time within eight different time intervals (3, 6, 9, 12, 15, 18, 21 and 24 hours).

Kalvningsintervall hos svenska köttkor : finns det genetisk variation som kan användas i avelsarbetet?

The Swedish beef cattle population is growing when the dairy cattle become fewer. The fertility of the beef cows is important for the profitability in beef cattle production. Today there is no genetic evaluation for female fertility in Swedish beef cows. The purpose of this study was to see if calving interval can be used in the genetic evaluation as a measure of female fertility in beef cows. For this purpose the variation in calving interval for beef cows of different breeds and ages registred in KAP was studied.

Sjukdomsfrekvens och utslagningsorsaker hos kor med 12 respektive 15 månaders kalvningsintervall

The incidence of many of the most common diseases in dairy cattle has been proven to be highest during the time closest to calving. It is possible that the current breeding strategy with 12 month calving intervals increases the risk for disease in dairy cattle, which is problematic concerning both animal welfare and for economic reasons. The economic incentives behind a calving interval of 12 to 13 months have mainly been based on milk- and feed- costs and no costs due to diseases or fertility disturbances have been included.The aim of this study was to see if a lengthening of the calving interval would result in lower disease frequency. The hypothesis is that cows with a planned calving interval of 15 months have a lower disease incidence than cows with a calving interval of 12 months due to less number of calvings. Therefore the difference in disease frequency should be larger when compared over a long period of time, such as over lifetime, since cows with a longer calving interval experience fewer calvings.The study was performed between August 17th, 1994, and January 24th, 2007.

Can increased activity recorded with help of activity monitoring sensor indicate an upcoming calving?

The purpose of this study was to find out if motion movements, e.g. number of lying bouts and lying time with a registered activity monitoring sensor can detect an impending calving and thereby be used as a measure and an indicator for an upcoming calving. For this, automatically step sensors were used and were attached to one of the cows? hind leg. The sensor registered the individual step and movement activity of the cow.

Introduction of heifers to an automatic milking system

Automatic milking systems (AMS) are part of a growing trend in Sweden and the number of milk-producing farms is decreasing rapidly. One main reason for the AMS is its ability to facilitate work for the farmer. The effects of introduction prior to calving have not been documented earlier and farmers are not in agreement, however they seldom see a problem with the introduction. The aim of this report is to find differences between two groups of heifers, where one group is trained i.e. introduced to the AMS before calving and the other group is introduced after calving.

Factors affecting the heifer´s age at pregnancy

Several factors affect the heifer´s growth and development, the newborn calf´s feeding of co-lostrum during its first hours of life is one important factor. The colostrum contains higher amount of immunoglobulins and insulin growth factors compared to matured milk. A high intake of immunoglobulins from colostrum results in a high blood concentration of immuno-globulins until the age of eight months. This leads to a lower incidence of diseases that can affect the growth and development negatively. Diarrhea is the most common disease in calves younger than 30 days.

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 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).

Genetiska och epigenetiska samband mellan näringsförsörjning och fertilitet hos mjölkkor

The dairy cow?s ability to resume estrus after calving and to conceive is affected by their metabolic status after calving. For high yielding cows there is a high risk that the feed intake will not be sufficient to cope with the increased energy demands after calving, and the cow will end up in a state of negative energy balance. Energy balance can be measured in various ways, for example by body condition score or by plasma concentration of several metabolic hormones and metabolites. After calving, endocrine pathways stimulate tissue mobilization; insulin signaling is blocked, the concentration of insulin-like growth factor-1(IGF-1) and leptin decreases, and the concentration of growth hormone (GH) increases.

Fertility before and after installation of Herd Navigator?

The fertility of dairy cows is of great importance in order to maintain high production. The decline in fertility of dairy cows the latest decades can have several explanations. The large emphasis on high yielding cows and the negative genetic correlation between milk production and fertility traits could be one of the main factors for impaired fertility. To find heats and inseminate the cow at the right time is crucial to receive high conception rate. Delaval has, in corporation with FOSS, developed Herd Navigator which is a management program that measure four biological parameters in the milk; progesterone, betahydroxybutyrate, lactate dehydrogenase and urea.

Site fidelity of a migratory species towards its annual range

Site fidelity, the behaviour of animals to return to areas where they have been before is a common trait in many species. The Scandinavian moose is known to show fidelity to its range, but to what extent, is little known. The landscape in Sweden changes in a predictable and unpredictable way and hence gives the opportunity to test the existence of fidelity. I used the kernel Brownian bridge method to estimate the home ranges of individual moose over consecutive years and estimated the overlap at the home range level. I also used Euclidian distance to look on calving site fidelity.

Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar :

Milkability or ease of milking, has higher importance today for Swedish dairy cattle producers after the introduction of milking parlours and automatic milking systems. Milkability is the cow?s ability to quickly milk out and be completely milked. There are several measures of milkability available. Today the farmer measures the traits subjectively in relation to the conformation scoring of the cow 30-270 days after her first calving.

Bristande mjölknedsläppning hos förstakalvare : en enkätstudie

Milk ejection in dairy cows can be inhibited if oxytocin is not released from the pituitary gland. The problem with inhibition of the milk let down is not new, but has recently regained interest. It is observed during different types of emotional stress, for example when cows are moved to an unfamiliar environment, during oestrus, changing from suckling to machine milking or when being milked for the first time. The aim of the study was to examine the extent of cows with disturbed milk ejection in Sweden. A survey was sent out to 1000 dairy farmers in order to collect data about herd size, housing systems and routines at calving and milking.

Samband mellan hull, underhudsfett, levande vikt och fruktsamhet hos SRB och SLB :

After parturition the energy demand for milk production is greater then the energy provided from the diet. The cow mobilises therefore body tissues to compensate for the energy loss. Live weight and body condition scores decreases as a consequence of the mobilisation. The aim of this study was to analyse the relationship between body condition score, live weight and subcutaneous fat depth measured by ultrasound and the changes during the lactation. Possible differences between Swedish Holstein (SLB) and Swedish Red and White Cattle (SRB) were also investigated.

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