Pieno kokybę apibūdina visa eilė rodyklių. Svarbiausias iš jų - somatinių ląstelių skaičius. Didėjantis SLS nurodo, kad karvė serga dažniausiai pasitaikančia ginekologine liga mastitu. Klinikiniu mastitu serga apie 1 – 2 proc. karvių. Dažniausiai serga karvės slaptuoju mastitu. Literatūros duomenys teigia, kad laktuojančių karvių bandose šiuo mastitu serga 43 – 47 proc. karvių. Svarbiausias slaptojo mastito požymis-padidėjęs somatinių ląstelių skaičius piene. Dažniausiai tešmens infekcija karvės suserga pirmaisiais laktacijos mėnesiais ir 80 proc. atvejų jos serga visą laktacijos laikotarpį. Sergant mastitu netenkama iki 25 proc. pieno per laktaciją. Vien tik dėl vieno tešmens ketvirčio uždegimo pieno per laktaciją sumažėja net iki 12 proc. Mastitu persirgusių karvių produktyvumas ne visuomet atsikuria toks, koks buvo iki ligos, nes negrįžtamai pasikeičia alveolinis audinys, tad kai kurias karves tenka išbrokuoti. Mastitą galima diagnozuoti pagal laktozės koncentracija elektrolitų sudėti ir SLS. Patogiausia ir pigiausia diagnozuoti pagal SLS. / The aim of this study was to find the non genetical influence facts in cows milk, for healthy cows and cows with secret mastitis. Scientific research work was carried out at the Department of Non-infectious diseases, Lithuanian Veterinary Academy and Practical Instruction and Research Centre LVA from 2005 to 2007. This work analyses data from dairy cow milk production. Experiments were carried out on two to seven year old black and white breed lactating cows, during the housing period. Data from 166 cows was used in this analysis. Inclusion criteria - somatic cell count higher than 400x 103/ml. We analyzed the influence of lactation on milk somatic cell count, cow age impact on productivity during lactation period on the number of somatic cells in the milk, parturition – to conception period length, season of the year. Increasing lactation number, was associated with elevated somatic cell count from 247, 3 until 392, 4 103/ml; and average milk yield per day also increased from 12,1 until 13,8 kg, milk fat increased from 4,34 until 4,38 percent, protein content increased from 3,15 to 3,30 percent. Milk lactose content decreased accordingly from 4,75 to 4,67 percent. Age positively influences milk productivity. This can be explained by lowered resistance to mastitis which is more frequent with age, cow automatic milking and supervision mistakes (Powell, et Al. 1997). According to literature data age and lactation period highly influences cow health and productivity. Age has... [to full text]

Modifying milk fat composition to enhance its content of valuable fatty acids (FA) is required to meet the needs of a society which is becoming better informed about the relationship between diet and health. Manipulating the cow’s diet is an effective, natural way to modify the amount and composition of milk fat of cows. The two main factors that affect the cow’s diet concern management system (MS; pasture vs. confinement), and supplementation of diets with lipid supplements. Marine oils specifically are fed to enhance milk with n-3 long-chain polyunsaturated FA (n-3 LC-PUFA). The effects of source of marine lipid supplement (LS; fish oil vs. microalgae) in the cow’s diet and its interaction with MS on milk fat composition have not been studied. Thus, the main objective was to determine the interaction of MS and LS on milk FA profile and on expression of lipogenic genes in mammary, adipose and liver of lactating dairy cows. Compared with cows in confinement, grazing cows produced milk fat with lower content of unfavorable FA (12:0-16:0), while increasing the levels of beneficial FA including cis-9 18:1, 18:3 n-3 and conjugated 18:2. Feeding either fish oil or microalgae improved levels of n-3 LC-PUFA and reduced those of 16:0 in milk fat regardless of MS, but concurrently increased the level of other trans 18:1 isomers at the expense of trans-11 18:1. The reduced secretion of 12:0-16:0 in milk from grazing compared with confined cows was associated with lower mammary expression of lipogenic genes suggesting that part of the effect of MS on milk FA profile is mediated transcriptionally. The effect of LS on lipogenic gene expression was tissue specific with the greatest response to treatment observed in liver despite its minor role in lipogenesis in cattle relative to the mammary and adipose. Major conclusions were that milk produced in pasture systems has a more healthful FA profile than that of confinement systems, and that MS and LS have tissue specific effects on lipogenic gene expression in dairy cattle which have important effects on cow performance and healthfulness of the milk FA profile.

This thesis is an investigation of the interactions of insulin resistance (IR), metabolic markers, neutrophil function, and reproductive health in peripartum dairy cows, including the evaluation of a hand-held glucometer for diagnosis of IR. The neutrophil functions of interest were oxidative burst and phagocytosis capacity, and reproductive diseases were endometritis and cervicitis. A total of 81 Holstein cows were enrolled 3 wk prior to expected calving date from November 2010 until October 2011, and were followed until 5 wk postpartum. Known markers of IR, neutrophil function, and disease were monitored through this period. The hand-held glucometer was identified as a useful alternative to laboratory measurements of glucose. Markers of IR influenced phagocytosis capacity and reproductive disease. High haptoglobin concentrations were associated with increased risk of reproductive disease and diminished oxidative burst function. Metabolically related inhibition of neutrophil function may be important in development of reproductive disease. / National Sciences and Engineering Research Council of Canada, Ontario Graduate Scholarship Program

Biological factors regulating feed efficiency were investigated in replacement beef heifers to establish factors that differ between efficient and less efficient animals. Feed efficiency, measured as residual feed intake (RFI) adjusted for body ultrasound measurements, was determined in forty-seven cross-bred heifers. Reproductive differences between efficient (low RFI) and less efficient (high RFI) heifers were examined. Low RFI heifers had an earlier age at both sexual maturity (P=0.08) and conception (P=0.08), and delivered heavier calves (P=0.006). The potential of fecal progesterone metabolites (FP4M) as an indicator of sexual maturity was examined. Measurements of FP4M present a promising non-invasive alternative technique for determining the onset of sexual maturity. A subset of 36 heifers was used to determine if plasma triiodothyronine (T3) concentrations could be used to predict feed efficiency. Triiodothyronine concentrations a correlation of 0.58 (P=0.001) to those from a quadratic prediction model of RFI in heifers sampled as yearlings. / Research into reproductive characteristics associated with residual feed intake, and to determine the effectiveness of the thyroid hormones as a screening tool for feed efficient animals. / OMAFRA (Ontario Ministry of Agriculture, Food, and Rural Affairs) through the Farm Innovation Program, Agriculture Canada through the Growing Forward Project, the Canadian Cattlemen’s Association through the Beef Cattle Research Council, and the Ontario Cattlemen’s Association.

Identifying molecular mechanisms regulating cellular energy utilization may lead to increased understanding of maintenance energy cost and improved feed efficiency in beef cows. Three experiments were conducted to characterize measures of residual feed intake (RFI) in pregnant beef cows; to examine the effects of moderate dietary restriction on visceral organ mass and proteins relating to energy metabolism; and to investigate the influence of pregnancy on visceral organ mass and proteins relating to energy metabolism. The first experiment combined data from five experiments using 321 pregnant Angus × Simmental cows. Including ultrasound fat measures and diet/management information increased the feed intake prediction model R2 by 7.3% and > 20%, respectively. Individual experiment RFI models varied greatly in accuracy. In the second experiment, 22 pregnant beef cows were fed at 85% (LOW; n=11) or 140% (HIGH; n=11) of net energy requirements during mid- to late-gestation. Tissue samples from liver, kidney, muscle, ruminal papillae, pancreas, and small intestinal muscosa were collected. Western blots were conducted to quantify abundance of: proliferating cell nuclear antigen, ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; peroxisome proliferator-activated receptor gamma, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), and 5’-adenosine monophosphate-activated protein kinase and phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase for liver and kidney; and uncoupling protein 2 for liver. Cows fed HIGH had greater (P ≤ 0.04) ADG and final BW than cows fed LOW. Ubiquitin abundance in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1α in liver was greater (P = 0.03) in cows fed HIGH. In the third experiment, 18 pregnant (PREG; n =9) or non-pregnant (OPEN; n=9) Angus × Simmental cows were fed for ad libitum intake during mid- to late-gestation. Tissues were weighed and collected and analyzed for protein abundance as described in the second experiment. Liver mass was lower (P ≤ 0.02), abundance of Na+/K+-ATPase was greater (P =0.04) and rumen pAMPK abundance was increased (P = 0.006) in PREG cows. These experiments indicate that measuring RFI in pregnant cows may pose some challenges, and nutrient restriction and pregnancy can influence molecular factors influencing feed efficiency. / Financial support was provided by Canadian Beef Cattle Industry Science Cluster, through funding provided by the Beef Cattle Research Council and Agriculture and Agri-Food Canada, Agriculture Adaptation Council-Farm Innovation Program, Ontario Ministry of Agriculture, Food and Rural Affairs, and the Ontario Cattleman’s Association.

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In Quebec, 62% of agricultural land is devoted to forage production and 20% of this is pasture. Pasture management provides the opportunity for farmers to maintain and improve the productivity of agricultural land, and to engage in sustainable ruminant production. An experiment was conducted on 42 hectares of pasture land to study the impact of management intensive grazing (MIG) on cow-calf productivity. The pasture area was divided into 18 paddocks and the experiment was conducted as a randomized complete block design with two blocks. The treatments were arranged as a 3 x 3 factorial of stocking rate and rotational frequency. The stocking rates (SR) were 0.5, 0.7, and 0.9 hectares per cow (HSR, MSR and LSR respectively); the rotation frequencies (RF) were two days, six days and continuous grazing (2d, 6d and C). Sixty-one purebred Angus cow-calf pairs were randomly assigned to each of the nine treatments, and the animals were grazed during two consecutive grazing seasons (1997 and 1998). Hay harvested early in the season was used for pasture supplementation late in the season. Increasing RF had no effect (P > 0.05) on forage mass available. Increasing SR from 0.9 to 0.5 cow-calf pairs ha -1 resulted in a linear reduction (P < 0.01) in individual cow gain, but increasing the SR caused a linear increase in cow gains ha-1. Calf gain ha-1 increased linearly (P < 0.01) in response to SR, but was unaffected (P > 0.05) by RF. A system of 6d rotation and high SR generated the greatest net revenue. The study showed little benefit of MIG on animal performance, but substantial benefits on efficiency of land use and economic performance.

The health and productive output of dairy cows can be closely correlated to individual cow feed intake. Being able to monitor feed intake on a daily basis is beneficial dairy farm management. Each cow can be addressed individually with minimal time required from those working with the animals. This is essential as time management is closely tied to resource management in a dairy operation. Anything that can save time and resources and increase profitability and herd health is a paramount advantage in dairy farming. This study examined the use of machine vision structured light illumination three-dimensional scanning of cow feed to determine the volume and weight of feed in a bin before and after feeding dairy cow. Calibration and control tests were conducted to determine the effectiveness and capability of implementing such a machine vision feed scanning system. Such a system is ideal as it does not obstruct workflow or cow feeding behavior. This is an improvement over existing systems as the system in this research study can be implemented into existing farm operations with minimal effort and costs.

Compost bedded pack (CBP) barn design and pack maintenance procedures vary considerably, making advising and problem-solving challenging. One objective of this research was to characterize herd performance and management practices employed by Kentucky CBP managers (42 farms and 47 CBP facilities). Producer satisfaction, changes in historical bulk-tank somatic cell count, and improvement in herd performance parameters after transitioning to a CBP barn support reported CBP barn system benefits. Daily milk production increased from before moving into the CBP barn to the second year after (29.3 ± 0.3 vs. 30.7 ± 0.3 kg, respectively; P < 0.05) for farms using the CBP barn as the primary housing facility (n = 8). Increasing stirring frequency, stirring depth, and ambient temperatures increased pack temperature. Increased drying rate decreased CBP moisture. Increased 20.3 cm depth CBP temperature and ambient temperatures improved cow hygiene. Mastitis-causing bacteria thrive in conditions similar to optimal composting bacteria conditions, making reduction of these bacteria difficult in an active composting environment. Producers must pay attention to other management areas where preventive measures can be employed. The New Dairy Housing Investment Analysis Dashboard provides users an interactive and flexible decision tool to make more informed facility investment decisions.

The objectives of this research were to compare lying time, milk yield, rumination time, hock score, stall cleanliness, and stall temperature for 97 cows (Holsteins (n = 71), Jerseys (n = 10), and crossbreds (n = 16)) housed on Dual Chamber Cow Waterbeds™ (DCCW, Advanced Comfort Technology, Reedsburg, WI) or conventional rubber mattresses (MAT). This study was conducted at the University of Kentucky Coldstream Research Dairy Farm from January 18, 2012 to May 3, 2013. Lying times were longer (P < 0.01) for cows housed on the DCCW (10:32 ± 0:13) compared to cows housed on the MAT (9:47 ± 0:15). Milk yield was not different (P ≥ 0.05) between cows housed on the DCCW or MAT. Rumination times were greater (P = 0.03) for cows housed on MAT (6:44 ± 0:08) compared to cows housed on DCCW (6:29 ± 0:08). Hock scores were lesser (P = 0.02) for cows housed on DCCW (1.86 ± 0.03) compared to cows housed on MAT (1.97 ± 0.04). Stall cleanliness was not different (P ≥ 0.05) between the DCCW and the MAT. The DCCW stall temperature was warmer (P < 0.01) (13.29 ± 0.21 ⁰C) than the MAT (10.52 ± 0.21 ⁰C).