The aim of this study was to investigate the relationship between sleep, photoperiod, Milk yield and hormones connected to milk formation. Variations of prolactin (PRL) and Insulin-Like growth factor-1 (IGF-1) in plasma were measured during two different light programs. The light programs consisted of either 24 hours of light (L24:D0) or four hours of light and 20 hours of darkness (L4:D20). Five cows of the Swedish Red breed were used in a cross-over experiment and each light program consisted of five days. Milk yield was measured at every milking and milk samples were analyzed with regard to fat, lactose and protein.

Milk yield levels in dairy cows are influenced by many factors such as nutrition, breed, health status, management and environment. This study was conducted among small scale farmers in Zambia, where the climate can be dry for up to six months per year and cause a lack of green pasture for livestock and on-farm produced feed. The purpose of this study was to identify management factors that can influence Milk yield at small scale dairy farms in Zambia, and present advice that could improve productivity, without the need of expensive investments. The study included semi-structured questionnaires presented to the farmers (n=29) including questions about cattle management and milk production. Testing of somatic cell count (SCC) with DCC (DeLaval Cell Counter) from herd milk samples (n=56) and observation of housing and animal body condition on-farm was also made.

There are various arguments for using total mixed rations (TMR) or not. Cows can easily become fat and thus poorly utilize the feed while it can be stated that TMR also has a positive effect on cows? health and wellbeing as the rumen environment is more constant than when separate feeding is applied. Studies do show that that especially low yielding cows kept in groups get fatter when fed TMR. The overfeeding implicates higher feeding costs. This study included 10 herds where 5 had TMR and 5 hade separate feeding of forage and concentrates.

Swedish goats are mainly held for cheese production and therefore, both milk quality and composition are of great importance for dairymen. Today, only few data exists on milk composition from Swedish dairy goats and the casein content is still unknown. One way to reduce the work load for goat farmers and increase animal welfare can be to keep goats and kids together for longer periods. The aims of this study were to investigate how Milk yield and composition were affected when kids suckled their dams during 8 weeks, and to measure the casein content on farm level by a mid-infrared spectroscopy method, previously calibrated for goat milk. Lactating goats were kept in two different MIX- systems where the dams are both suckled and milked.

When facing the fact that high yielding dairy cows has an increasing energy requirements, the practice of adding lipid supplements such as concentrates rich in palm oil and/or palm oil industry by-products become more common. Palm oil containing high levels of C16:0 causes high levels of free fatty acids (FFA) which are linked to larger milk fat globules (MFG) which affect the reaction of lipolysis resulting in rancid flavour and processing problems. Instead of using palm oil, rapeseed oil rich in C18:1 C18:2 can be used. In order to evaluate the effect of added C18:0 and C16:0 on milk lipolysis, 30 Swedish Red lactating dairy cows including 15 multiparous (MP) and 15 primiparous (PP) cows were randomly divided in three groups resulting in 3 10 cow-groups (5 PP and 5 MP cows per group) and fed one out of three concentrate mixtures: control (C), a standard concentrate mixture with no fat added; palmitate (P) as C plus the addition of palmitate methyl ester (10 % in DM basis); and stearate (St) as C plus the addition of stearate methyl ester (10 % in DM basis). Milk yield was registered, and milk samples were collected and analysed for milk composition, FFA content and size of MFG.

The purpose of this review was to study the cow eye physiology, focusing on how it registers light, and to see how light affects the cow?s Milk yield. It has been showed in studies that more hours of light per day (16 hours of light a day) as opposed to about 9-12 hours of light a day, increases Milk yield for dairy cows. This review contains suggestions on how this is connected with the physiology of the eye. Vision is an important sense for many mammals, and is used to check out the animals surroundings. Sensor cells in the eyeball help in turning photons from the light into signals to the brain.

The aim of the study was to investigate if the Grazemore Decision Support System (DSS) is able to provide a grazing management strategy that gives a high utilisation of grazed grass in milk production in the north of Scandinavia. To do this, a grazing experiment was planed and performed during the summer 2005. Simulations in the DSS were run to get a suggestion of how the cows should graze, grazing calendar 1. Deviations and updates during the season resulted in the simulated grazing calendar 2. During the experiment, the actual Milk yield was recorded twice weekly. The difference between actual and predicted Milk yield by Grazemore DSS was analysed statistically with regression analysis and the mean square prediction error (MSPE) was estimated.

Approximately 20% of the milk within the udder of a cow is stored in the cistern and immediately available for milk removal, while activation of the milk ejection reflex is required for removing the remaining milk stored in the alveolar compartment. The aim of this literature review is to describe, evaluate and consider implications of the three different suckling activities that the calf displays during a suckling bout. In terms of milking, these phases are represented by pre-stimulation, stimulation during milking and post-stimulation. Pre-stimulation is commonly performed in order to induce the milk ejection reflex, whereby the hormone oxytocin is released and the alveoli in the secretory tissue are contracted. Time requirements regarding pre-stimulation must be considered in relation to lactation stage and milking interval.

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.

Automatic milking systems (AMS) provide the opportunity for less manual labour and an increased milking frequency. But in order to reach an optimal milking frequency a well-functioning cow traffic is crucial. There are many factors affecting cow traffic but one factor that has not been studied thoroughly yet is the effect of different light intensities during the night, 22.00 h to 05.00 h. Therefore the aim of this study was to determine the effect of different light intensities during the night on number of selection gate passages (GP), milking frequency and Milk yield. The study was conducted as a Latin square were three light intensities were applied: LOW (11 ± 3 lux), INT (33 ± 1 lux) and HIGH (74 ± 6 lux), in three different herds.

A totally mixed ration (TMR) is a mixture of all the necessary feed components for the cow. She will eat the exact same feed in every bite which will make the rumen pH more stable and always supply her with a constant proportion between roughage and concentrate. This will make it possible for the cow to eat more dry matter (DM) a day because the fibre requirements are fulfilled. If a part of the concentrate is given separated from the mixture it is called partly mixed rations (PMR) and is almost always used when using an automatic milking system (AMS). When using TMR and PMR it is important to have a high hygiene, be accurate when mixing the feed and to look after cows in a good and strict way. The aim of this study was to document different farms with PMR in an AMS to see which routines they have and how they are managing their production.

Dairy cows transform grass to milk with help from ruminal microorganisms that can digest indigestible fiber in their feed. The digestive system of the cow is adapted to a diet consisting of forage and disorders like acidosis, laminitis and abomasal displacement can occur if the feed contains too much starch. To achieve the highest production possible the cow has to be given a high amount of concentrate or grain as the difference in Milk yield is significant, approximately 1000 kg energy corrected milk per cow and year between conventional and organic cows that are fed a lower versus a higher share of forage. If the cow shall be able to eat the same amount of energy from forage as from grain or concentrate the eating- and rumination time gets longer and she might not be able to eat enough, which will result in a lower Milk yield and will make it harder for the cow to recover from the negative energy balance that originate from the beginning of the lactation. Fat and in a sense protein content differs also depending on if the cow is given a high or low share of forage..

Ravelsmarks gård have now reached the stage when there are few options for the future. The options are either a construction of completely new farm buildings or a winding up of the milk production. Present on the farm today there is 65 dairy cows plus recruitment. 44 cows stand in long-stalls and 20 cows stand in short-stalls. The objective of this study was to examine the profitability of a completely new cowshed. In order to get costs for investments different milking systems and equipment for feedstuff have been compared. The systems in the investment budget have been chosen on recommendations from advisers, salesmen and on the basis on what is suitable for the farm. One system where a so-called mix feeder wagon is used for the roughage seemed to be best suited for Ravelsmark. The different prices obtained for the manure well show that there are possibilities to decrease the investment costs.

Feed costs constitute a large part of the expenses of dairy farmers. Pasture is a high quality feed with a low cost. However, feeding with concentrates has been shown to enhance Milk yield (Leaver, 1985; Bargo et al., 2003; Stockdale, 2004). The purpose with this study was to investigate how Milk yield and milk composition were affected as the concentrate proportion in the diet decreased. Pasture behaviour was examined to see if the different concentrate levels affected the time cows spent grazing and ruminating.

The production of cheese is in continuous development with objectives to in-crease productivity, achieve changes in shelf life and functional properties of the products. One concept in the development is to substitute milk fat with vegetable fats and oils in the manufacture of cheese. The objective of this study was to investigate effects on cheese yield and cheese quality of 4 different semi-hard analogue cheese products produced by substituting milk fat with vegetable fat, each analogue cheese with a specific mixture of vegeta-ble fat. As reference a cheese produced with anhydrous milk fat was used. The yield and recovery of fat and protein were determined by recording the weights of each cheese direct after press and after 20±2 days of storage and analysis of the composition of the cheeses after 20±2 days of storage. The cheese was fur-ther subjected for texture profile analysis in a TA-XT Plus Texture Analyser and analysed with Differential Scanning Calorimetry (DSC) to examine whether the fat behaves similar in the cheese as in pure form in respect to its thermal properties. The cheese yield was not significantly different when using different fats. Differ-ent amounts of water were absorbed during the water cooling.