Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Lactating dairy cows from 2 Kansas farms were used to determine the effectiveness of exogenous progesterone in the form of an intravaginal insert (controlled internal drug release; CIDR) in conjunction with an ovulation-synchronization protocol. Cows were enrolled in a Presynch + Ovsynch protocol after parturition, where they received 2 injections of PGF[subscript]2[alpha], 14 d apart (Presynch) beginning between 30 and 36 DIM. Cows (n = 155) detected in estrus after the second PGF[subscript]2[alpha] injection of Presynch were inseminated (early AI). Remaining cows were assigned randomly to be treated with the Cosynch-72 protocol (GnRH 12 d after last Presynch PGF[subscript]2[alpha] injection, PGF[subscript]2[alpha] 7 d after GnRH, and timed AI + GnRH injection 72 h later) and served as controls (n = 159), or to be treated with the Cosynch-72 protocol and receive a progesterone insert (Ovsynch + CIDR; n = 175) for 7 d between GnRH and PGF[subscript]2[alpha]. Blood was collected at d −22 and −10 (relative to TAI at d 0) to determine cycling status based on progesterone concentrations and again at d 11 post AI to determine luteal competency. Treated cows were assigned body condition scores (BCS) on d −22 and −10. Pregnancy status was confirmed by palpation of the uterus per rectum and its contents on d 38 post-timed AI and verified again 4 wk later. Treatment with the progesterone insert increased timed AI pregnancies per AI in Cosynch- 72 + CIDR-treated cows when compared with controls (38 vs. 24%), but did not differ from early AI cows (38%). Pregnancy loss was numerically less in progesterone-treated cows than in controls (4.4 vs. 11.8%). Our study shows that increased pregnancies per AI can be achieved by the use of a progesterone insert in a reduced population of cows not yet inseminated, but treated with a progesterone insert.

Master of Science / Department of Animal Sciences and Industry / John F. Smith / A series of experiments was developed to investigate how Korral Kool® (KK) systems work in arid climates to prevent heat stress on dairy cows. These experiments were conducted during summer on a commercial dairy farm in eastern Saudi Arabia. In the first experiment, the core body temperatures (CBT) of 63 multiparous cows were evaluated when KK were operated for 18, 21 and 24h/d. Animals were housed in 9 different pens, which were randomly assigned to treatment sequence in a 3x3 Latin square design. In the second experiment, 21 multiparous and 21 primiparous cows were housed in 6 different pens, which were randomly assigned to sequence of treatments (KK operated for 21 or 24h/d) in a switchback design. In the third experiment, 7 primiparous and 6 multiparous lactating cows were assigned to one of two pens, which were randomly assigned to treatment sequence in a switchback design. Treatments in the third experiment were KK used with or without feedline soakers 24h/d. In the fourth experiment, 20 multiparous cows were randomly assigned to one of two pens, which were randomly assigned to treatment sequence in a switchback design. Treatments in this experiment were KK operated for 24h/d while feedline soakers were operated for 12h/d. In the fifth experiment, 2 different sizes of KK were compared (BIG and SMALL); 48 multiparous cows were randomly assigned to 8 pens and pens were randomly assigned to sequence of treatments (KK were operated for 21 or 24h/d) in a switchback design. Results demonstrated that for multiparous cows in desert climate conditions, it is advisable to operate KK systems continuously regardless of the size of KK system used, whereas KK operating time could potentially be reduced from 24 to 21h for primiparous cows. Reducing operation time should be done carefully, however, because CBT was elevated in all treatments. Feedline soakers complementing KK systems decreased the CBT of dairy cows housed in desert environments. However, the combined systems were not adequate to lower CBT to normal temperatures in this extreme environment.

This study investigated the hypothesis that the particulate content of milk, as monitored with particle counters, is correlated to the health status of lactating dairy cows, in particular the condition mastitis. Twenty Holstein cows were monitored from the very first day of clinical mastitis outbreak until complete recovery from the disease. During the experiment, the changes in particle behaviour in all four quarters and mixture of milk from all of them were measured. For each sample the following parameters were measured: somatic cell count, fat content, lactose and protein concentration, number and size distribution of milk particles, electric conductivity and diameter of milk fat globules. In total over thirty mastitis outbreaks were observed and monitored throughout, including the first phase of this study when over three thousand samples of foremilk were collected and examined. An operational protocol and particle monitoring device were designed with the help of a commercial company Facility Monitoring Systems Ltd (FMS), Malvern. A particle counter and Peak Height Analyser (PHA) were used to monitor particulate content of milk and a compound phase contrast microscope was used to identify milk particles by photographic visualisation and to establish their diameter. It was observed that the number of particles, milk fat globule diameter and somatic cell counts were stable during periods without udder inflammation. Mastitis caused great changes in these parameters. Both milk particulate size and number were significantly affected by clinical and subclinical form of inflammation (change to the particulate behaviour). It was observed that the changes to the volume median diameter (VMD) of fat globules became evident a few days before clinical signs were present. Results obtained from a particle counter and the PHA were in agreement with data obtained by microscopy. Major changes were recorded in the number of total particles in milk before and during the outbreak of mastitis. Further research showed that changes took place in the pattern of particulate behaviour without visible signs of disease; additional data established that subclinical mastitis can be also identified through the monitoring of particles in milk. In summary monitoring of the behaviour (changes to size and number) of milk fag globules (MFG) can be used as an early indicator of the onset of mastitis. In addition data collected during study produced strong evidence supporting the theory of the interdependence of the quarters within the udder. It was found that the coefficient of correlation for size and number of particles for all four quarters within the udder was statistically significant. Particle counts and the VMD values behaviour were similar for the four quarters. This relationship was observed for all monitored animals. Moreover, the same relationship was also observed during both clinical and subclinical outbreaks of mastitis. Somatic cell count was affected only in an infected quarter while particulate content of milk ―responded‖ to disease in all four quarters within the udder (even if only one was infected). These results were the most surprising and unexpected outcome, suggesting that four quarters within the udder work together as one organ not four separate units. It was observed that the mean MFG cannot be used as a baseline to test individual animal deviations due to the unique particle profile of each observed animal. In all monitored animals particle counts obtained from PHA was found to be in the range of 1011 to 1013 with an average of 1012 particles per ml. The number of particles recorded in mastitis for one animal was at the healthy level for another. The particle pattern became a finger print for each animal and therefore MFG behaviour cannot be compared between animals. Following the first phase of the study the monitoring period was set at 15 to 20 days. This protocol allowed for minimising the influence of any other parameters on particles, which may influence the outcome of an experiment e.g. the number of particles in single samples detected by the particle counter. It was also essential to understand how the age, nutrition and stage of lactation might influence the particles and affect the results. Therefore two animals were chosen to be examined during their lactation. The analysed data did not present enough evidence to establish the relationship between nutrition and milk fat globules size and number. However to better understand this association additional studies should be carried out. Further work is required to optimise the monitoring device and build a fully automated system which will allow collecting and analysing data from the whole herd. This study proposed that particle pattern is unique for each animal – like a finger print. More research is needed to better understand the mechanism behind milk fat globules synthesis during inflammation. The results obtained during this study provide new evidence with regard to physiological changes within the udder before and during mastitis outbreak and supported the theory of interdependence between quarters within udder. The particle count in milk can be used as an indicator of the health status of the single animal. Combined the PHA and microscope can be used as a new tool to determine and monitor the particle count in milk. The understanding of the particulate behaviour will help to minimise the chance of mastitis outbreak by early detection and also to reduce the chance of the cross-contamination between animals during the milking process. Milk fat globule size and number can be used as an efficient indicator of the onset of mastitis.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: In this study, five trials were conducted to examine in vitro and in vivo degradation, excretion and absorption parameters of melamine (MEL) in dairy cows that have not been studied before or where limited information is available. The first two trials were in vitro studies conducted to determine the extent of MEL degradation in rumen liquor and the effects of MEL on ruminal ammonia (NH3) and volatile fatty acid (VFA) concentrations. For both trials, rumen liquor was collected from ruminally cannulated lactating Holstein cows. For the first and second trial, rumen liquor was collected from three and two cows, respectively. For both trials, Erlenmeyer flasks contained 1 g substrate and 100 mL incubation medium consisting of 20 mL rumen liquor and 80 mL reduced buffer solution. In the first trial, each flask contained 100 mg of MEL, resulting in an initial MEL concentration of 1000 mg/L. The flasks were incubated at 39° C for 0 (Control), 6, 24 or 48 hours under strictly anaerobic conditions. In all the trials, MEL concentrations were determined by LC/MSMS. MEL degradation was low after 6 and 24 h of incubation (3.2 and 5.5%, respectively) and increased to 13.6% after 48 h of incubation. In the second trial where VFA and NH3 concentrations were determined, the flasks contained either 0 (Control), 0.2 (T1) or 0.4 mg (T2) of MEL. The flasks were incubated for 6, 24 or 48 h. Treatment had no effect on individual or total VFA concentrations or NH3 concentrations at 6 and 48 h. At 24 h, T2 resulted in an inexplicable higher NH3 concentration. This study showed that the addition of melamine would not result increased rumen NH3 concentrations in vitro. Melamine would also not affect the production of different VFA’s. Therefore, it was concluded that the rumen micro-organisms present in rumen liquor would be unable to utilize MEL as a source of nitrogen and that the microbial production of VFA’s remains unaffected by the presence of MEL. In the third trial, MEL excretion in lactating cows was determined. Five cows were randomly allocated to treatments according to a 5 x 5 Latin square design. Cows received the treatment diets for 7 d followed by 8 d of MEL withdrawal during each of the five periods. The experimental treatments were formulated to provide a daily MEL intake of 0 (M0), 500 (M1), 1000 (M2), 5000 (M3) or 10000 mg (M4) via 15 kg of dairy concentrate pellets. Calculations based on the work of Newton & Utley (1978) suggested that a melamine intake of 0.16 g/kg of live weight would not result in detrimental health effects of ruminant animals. Therefore, a 600 kg lactating dairy cow should not be at risk when consuming 100 g of melamine. In this trial, the highest melamine treatment (M4 = 10 g/d) included a 10-fold safety factor from the suggested safe amount from the work of Newton & Utley (1978) and should not pose a health risk to the cows. Treatments had no effect on DMI, milk yield or milk composition. MEL was detected in the milk 8 h after initial MEL ingestion, increased rapidly and peaked on d 3 and was undetectable after 8 d. Treatments had no effect on MEL excretion efficiencies which ranged from 1.5 to 2.1%. The mean apparent digestibility of MEL was 78%. Mean faecal and urinary MEL excretions were 22 and 54 % of ingested MEL, respectively. Higher milk, urine and faecal MEL concentrations were observed with higher levels of dietary MEL. It was concluded that MEL appeared in the milk soon after first ingestion and a withdrawal period of 8 d was required for all milk, faecal and urine samples to reach undetectable levels of MEL. Urine and faeces were the primary routes for MEL excretion. The fourth trial was conducted to determine MEL absorption by the mammary gland in lactating dairy cows through arterio-venous (A-V) difference. Five cows received 10 g of MEL/d for three consecutive days. Day 3 of the trial was selected for commencement of blood sampling as previous studies (Cruywagen et al., 2009; Shen et al., 2010; Sun et al., 2011) reported the milk melamine concentration to reach a peak on d 3 of continuous melamine consumption by dairy cows. Early on d 3, catheters were inserted into the caudal superficial epigastric vein (milk vein) and caudal auricular artery. The blood sampling period commenced after residual milk removal from the udder following oxytocin administration. Blood from both locations were collected hourly for 9 hours. Following the final blood collection, oxytocin was administered again, catheters were carefully removed and cows were milked immediately thereafter. All blood samples were centrifuged and the decanted plasma was analysed for MEL, as well as for amino acid contents to calculate mammary blood flow. The positive MEL flux (calculated from A-V difference) confirmed net absorption of MEL into the mammary gland with an efficiency of absorption of 0.29%. Melamine excretion into milk was 5.63 mg/h. The mean plasma and milk MEL concentrations were 5.2 and 3.9 mg/kg, respectively. Melamine excretion efficiency to milk, expressed as percentage of the ingested amount, was 1.47%. It was concluded that melamine ingested by cows will result in net MEL absorption by the mammary gland, but that the absorption efficiency is low. The final trial of the study aimed to determine the effects that fermentation processes during the manufacturing of cheese, yoghurt and kefir would have on their MEL content if these products were made from MEL contaminated milk. Another objective was to determine if MEL in cheese would be degraded during the curing process. Cheese, yoghurt and kefir were made from milk with a MEL content of 6.77 mg/kg. The cheese was then cured for 2 wk at 6° C. The MEL contents of the yoghurt and kefir were 6.76 and 6.78 mg/kg, respectively, indicating that the different fermentation processes used in yoghurt and kefir production had no effect on their MEL content and that MEL was not degraded during the short fermentation periods. The percentage of milk MEL partitioned to whey and cheese were 97.4 and 6.5 %, respectively. It was concluded that the different fermentation processes involved during the manufacturing of yoghurt and kefir from MEL tainted milk did not decrease the MEL concentration. The milk MEL was predominantly partitioned to whey, with little MEL transferred to cheese. It was also concluded that MEL was not degraded in cheese during a 2-wk curing period. It was finally concluded that dietary MEL is readily absorbed by dairy cows and mainly excreted via the urine. The mammary gland has a low affinity for MEL absorption and approximately 2% of ingested MEL is excreted in the milk. When cheese is made from MEL tainted milk, the majority of MEL will concentrate in the whey fraction and only 6.5% will be present in the cheese. / AFRIKAANSE OPSOMMING: Vyf proewe is gedoen om in vitro- en in vivo-degradering, uitskeiding en absorpsie parameters van melamien (MEL) na te gaan waaroor daar min of geen inligting bekend was nie. Die eerste twee proewe was in vitro-studies, uitgevoer om die mate van MEL degradeerbaarheid in rumenvloeistof na te gaan, asook die invloed van MEL op rumen-NH3 en vlugtige vetsuur (VVS)-konsentrasies. Vir beide proewe is rumenvloeistof van lakterende, rumengekannuleerde Holsteinkoeie verkry. Vir die eerste en tweede in vitro-studies, was rumenvloeistof verkry vanaf drie en twee koeie, onderskeidelik. In albei proewe is 1 g substraat in Erlen-meyerflessies afgeweeg en 100 mL inkubasiemedium bygevoeg wat uit 20 mL rumenvloeistof en 80 mL van ‘n buffermedium bestaan het. In die eerste proef is 100 mg MEL by die substraat gevoeg, sodat die aanvanklike MEL konsentrasie in die flessies 1000 mg/L was. Die flessies is by 39° C geïnkubeer vir 0 (Kontrole), 6, 24 of 48 ure, onder streng anaerobiese kondisies. Met die beïndiging van die inkubasieperiode is 100 mL van ‘n 0.2 M perchloorsuuroplossing bygevoeg om enige melamien wat nie gedegradeer was nie, op te los. In al die proewe is melamienbepalings by wyse van LC/MSMS gedoen. Melamiendegradering was laag na 6 en 24 h inkubasie (3.2 en 5.5%, respektiewelik) en teen 48 h inkubasie het dit toegeneem tot 13.6%. In die tweede proef het die flessies 0 (Kontrole), 0.2 (T1) of 0.4 mg (T2) melamien bevat. Behandeling het geen invloed op individuele of totale VVS-konsentrasies by enige van die inkubasietye gehad nie en ook nie op NH3-konsentrasies by 6 en 48 h nie. Om een of ander onverklaarbare rede het die T2-behandeling gelei tot hoër NH3-konsentrasies by 24 h. Die gevolgtrekking is gemaak dat die byvoeging van MEL geen effek op rumen NH3-konsentrasies het nie en dat die mikroorganismes in die rumen nie daartoe in staat sal wees om MEL as ‘n stikstof-bron sal kan benut nie. In die derde proef is die uitskeiding van MEL in melkkoeie ondersoek. Vyf lakterende Holsteinkoeie is ewekansig aan vyf behandelings toegeken in ‘n 5 x 5 Latynsevierkantontwerp. Gedurende elke periode het koeie die behandelings vir 7 d ontvang, gevolg deur ‘n 8 d MEL-onttrekkingsperiode. Die eksperimentele diëte is geformuleer om ‘n daaglikse MEL-inname van 0 (M0), 500 (M1), 1000 (M2), 5000 (M3) of 10000 mg (M4) per koei/dag te verseker, toegedien via 15 kg/d van ‘n suiwelkonsentraat in pilvorm. Berekeninge gebasseer op die werk van Newton & Utley (1978) stel voor dat ‘n MEL inname van 0.16 g/kg lewende massa, geen negatiewe effek op herkouers se gesondheid sal hê nie. Dus, ‘n koei wat 600 kg weeg, sal geen skade lei deur die inname van 100 g MEL nie. In hierdie proef was die hoogste MEL behandeling (M4 = 10g/d) tien keer laer as die voorgestelde veiligheidsvlak van Newton & Utley (1978). Behandeling het geen invloed op DMI, melkopbrengs of melksamestelling gehad nie. Melamien is so gou as 8 h na eerste inname in die melk waargeneem, waarna die konsentrasie vinnig toegeneem het en ‘n piek na 3 d bereik het. Behandeling het geen invloed op die uitskeidingsdoeltreffendheid van melamien in melk gehad nie en waardes het gewissel van 1.5 tot 2.1%. Die gemiddelde skynbare verteerbaarheid van MEL was 78%. Die gemiddelde mis- en uriene-MEL-konsentrasies was 22 en 54%, onderskeidelik. Hoër melk-, mis- en uriene-MEL-konsentrasies is waargeneem namate die MEL-inhoud van die diëte gestyg het. Die gevolgtrekking is gemaak dat MEL spoedig na eerste inname in die melk verskyn en dat ‘n onttrekkingsperiode van 8 d benodig word voordat melk-, mis- en uriene-MEL onwaarneembare vlakke bereik. Uriene en mis is die primêre uitskeidingsroetes van ingenome MEL. Die vierde proef is onderneem om MEL-absorpsie in die melkklier met behulp van arterio-veneuse (A-V) verskille te ondersoek. Vyf koeie het elk 10 g MEL/d vir drie agtereen-volgende dae ontvang. Dag 3 van die proef is gekies vir bloedkolleksies aangesien vorige studies (Cruywagen et al., 2009; Shen et al., 2010; Sun et al., 2011) gewys het dat melk MEL op dag 3 van MEL inname, piek konsentrasies beryk. Vroeg gedurende die oggend van d 3 is kateters in die kaudale oppervlakkige epigastriese aar (melkaar) en die kaudale aurikulêre slagaar geplaas. Die bloedtrekkingsperiode het ‘n aanvang geneem direk nadat die koeie volledig uitgemelk is na toediening van oksitosien om te verseker dat soveel as moontlik residuele melk verwyder word. Monsters van veneuse-, sowel as arteriële bloed, is 9-uurliks geneem. Na die finale bloedtrekking is oksitosien weer toegedien, die kateters is versigtig verwyder en die koeie is direk daarna weer gemelk. Al die bloedmonsters is gesentrifugeer en plasmamonsters is ontleed vir MEL, asook vir aminosuursamestelling ten einde bloedtoevoer na die uier te bereken. Die positiewe fluks (bereken van A-V verskil) het bevestig dat netto MEL absorpsie in die melkklier plaasvind, met ‘n doeltreffendheid van 0.29%. Melamienuitskeiding in die melk was teen ‘n tempo van 5.63 mg/h. Die gemiddelde plasma- en melk-MEL konsentrasies was 5.2 en 3.9 mg/kg, onderskeidelik. Die uitskeidingsdoeltreffendheid van MEL na melk, uitgedruk as persentasie van ingenome MEL, was 1.47%. Die gevolgtrekking is gemaak dat MEL wat deur koeie ingeneem word, tot netto MEL-absorpsie in die melkklier sal lei, maar dat die absorpsiedoeltreffendheid baie laag is. In die finale proef is daar gepoog om die invloed van fermentasieprosesse gedurende die vervaardiging van kaas, joghurt en kefir op die produkte se melamieninhoud na te gaan indien die produkte van melamienbevattende melk gemaak sou word. ‘n Tweede doel van hierdie proef was om te bepaal of MEL in kaas gedegradeer kan word tydens rypwording. Kaas, joghurt en kefir is gemaak van melk wat ‘n MEL-inhoud van 6.77 mg/kg gehad het. Die kaas is vervolgens vir twee weke by 6° C rypgemaak. Die MEL-inhoud van die joghurt en kefir was 6.76 en 6.78 mg/kg, onderskeidelik, wat daarop dui dat die onderskeie fermentasieprosesse wat tydens die bereiding van joghurt en kefir plaasvind, geen invloed op hul MEL-inhoud gehad het nie en dat MEL nie gedurende hierdie kort fermentasieperiodes gedegradeer is nie. Die persentasie MEL na wei en kaas versprei was 97.4 en 6.5%, onderskeidelik. Die gevolgtrekking is gemaak dat die verskillende fermentasieprosesse betrokke tydens die vervaardiging van joghurt en kefir wat van melamienbesmette melk gemaak word, nie die MEL-konsentrasie verlaag het nie. Tydens die vervaardiging van kaas, word die MEL hoofsaaklik na die weikomponent versprei en baie min na kaas. Melamien word ook nie in kaas afgebreek gedurende ‘n verouderingsproses van twee weke nie. Die finale gevolgtrekkings is gemaak dat MEL maklik deur melkkoeie geabsorbeer word en dat die hoof uitskeidingsroete via urine is. Die uier het ‘n lae affiniteit vir MEL absorpsie en ongeveer 2% van ingenome MEL is in die melk uitgeskei. Wanneer kaas van MEL besmette melk gemaak word, sal die meerderheid van die MEL in die weifraksie konsentreer, met slegs 6.5% teenwoordig in die kaas. / The Hennie Steenberg Trust Fund, the Ernst and Ethel Erickson Trust and the National Research Foundation (NRF) for their financial support

Two experiments were conducted at the University of Kentucky, Eden Shale Farm, Owenton, KY to evaluate the use of MTB-100TM (Alltech, Inc., Nicholasville, KY) to alleviate the symptoms of fescue toxicity when lactating Angus x Beefmaster cows and their calves grazed endophyte-infected KY-31 tall fescue. Experiment 1 provided a carbohydrate based toxin adsorbent, MTB-100TM, ad libitum in a commercial mineral supplement to project a daily consumption rate of 0, 20 or 40 g of MTB-100TM per cow. Cows were weighed, assigned a body condition score (BCS) and hair coat score (HC), rectal temperatures were recorded and fecal grab samples were taken for ergovaline (EV) and lysergic acid (LA) analysis every 35 days for three grazing seasons (May to September). Calves were also weighed and assigned a HC score. Although MTB-100TM did not improve cow or calf performance, cows older than 4 years and those with greater Beefmaster breeding exhibited a higher tolerance to fescue toxicity than 2 and 3-yr-olds and cows with greater Angus breeding. Experiment 2 was conducted to evaluate the response of lactating beef cows and their calves to strategic supplementation with MTB-100TM. MTB-100TM was mixed with a complete mineral so daily intake was projected to be 0 or 20 g/cow. The experimental period extended from May 5 to October 2 and was divided into 3 strategic periods: P1 = May 5 to July 5; P2 = July 5 to August 31; P3 = August 31 to October 2. Treatments were either 0 or 20 g•cow-1•d-1 MTB-100TM within a period (Treatment 1 = 0, 0, 0; Treatment 2 = 20, 0, 20; Treatment 3 = 0, 20, 0; Treatment 4 = 20, 20, 0; and Treatment 5 = 20, 20, 20). Cow and calf performance was measured the same as Exp. 1, but every 21 days. Supplementation early in the grazing season tended to improve cow weight gain and body condition; however, there was no effect on calf performance. Fecal output of EV and LA did not increase in either experiment with supplementation. In conclusion, strategically invoked MTB-100TM consumption can increase performance of cows grazing endophyte-infected tall fescue forage.

Climatic conditions inside the dairy barn do not concern dairy farmers until those conditions begin to affect productivity and, consequently, profits. As heat and humidity increase beyond the cow's comfort levels, milk production declines, as does fertility and the welfare of the cow in general. To reinforce the cooling mechanisms currently used, this work proposes an alternative system for reducing the risk of heat stress. This innovative conductive cooling system does not depend on current weather conditions, and it does not require significant modifications when it is installed or during its operation. Also, the system circulates water that can be reused. Given that a review of the literature found very few related studies, it is suggested that each freestall be equipped with a viable prototype in the form of a waterbed able to exchange heat. Such a prototype has been simulated using Computational Fluid Dynamics (CFD) and later verified by a set of experiments designed to confirm its cooling capacity. Furthermore, this investigation sets the foundation for modeling temperature in a water supply system linked to the waterbeds. EPANET, a software program developed by the Environmental Protection Agency, simulates the hydraulic model. Its Water Quality Solver has been modified according to an analogy in the governing equation that compares mass to heat transfer and serves to simulate water temperature as the water is transported from its source to the point of delivery and then as it returns to the same source.

Analizuojama tipinių gyvulininkystės objektų darbuotojų darbo aplinka, būdingi kenksmingi veiksniai. Sudarytos tyrimų metodikos ir atlikti triukšmo bei dulkėtumo tyrimai tipinėje Lietuvai (iki 50 karvių) fermoje. Nustatyta, kad fermos darbuotojui triukšmo ekspozicija gali būti apie 83 dBA (žemutinė vertė prevencijos veiksmams pradėti yra 80 dBA), o dulkių koncentracija malant grūdus yra 55±21 mg/m3. Šioje darbo vietoje vyrauja (apie 90 %) iki 1 µm dydžio dalelės. Triukšmo ir dulkių kenksmingam poveikiui darbuotojo sveikatai sumažinti parinktos asmeninės apsaugos priemonės. / Analyzed of typical animal facilities staff work environment, characterized nuisances. Consisting of research methodology and make noise and dust tests in typical for Lithuania (50 cows) farm. It was found that the farm worker noise exposure may be about 83 dBA (more than lower exposure action value - 80 dBA), and dust concentration in the grain milling operation is 55 ± 21 mg/m3. In this workplace dominated (about 90%) particles to 1 µm size. Noise and dust harmful effects on the workers’ health to reduce selected personal protective equipment.

Forty-eight Holstein cows at Utah State Dairy Farm were blocked statistically according to date of calving, previous milk production, and numbers of lactation at parturition. The cattle were assigned randomly to one of four treatments within blocks. The four treatments included a base ration (control, treatment #1), base ration plus .8% of sodium bicarbonate (treatment #2), base ration plus .4% of magnesium oxide (treatment #3), and base ration plus both .8% of sodium bicarbonate and .4% of magnesium oxide (treatment #4). The research was conducted from February 1983 to November 1984. A formagraph was used to measure milk coagulation parameters and pH was determined. There was no significant difference in milk coagulation parameters or pH between the control and the buffer treatments. Milk parameters were significantly different in individual cow, week, and milk pH. Milk parameters did not appear to be dependent upon season. Curd firmness was significant in interaction of season and treatment. Significant variations in milk pH were observed in relation to week, season, and individual cow. Overall treatments, the clotting time, K20, and pH value increased each week, and A30 decreased each week. The milk parameters and pH in each treatment were significant between weeks except K20 and A30 in treatment #3, and A30 in treatment #2 (p>0.05). The clotting time and K20 were negatively correlated with firmness, and there was positive correlation between Ct and K20 as expected. Somatic cell count was positively correlated with clotting time, K20, and pH and negatively correlated with A30. Milk pH was the most significant and had positive correlation coefficient with clotting time and firming rate and negative correlation coefficient with curd firmness.

Master of Science / Department of Animal Sciences and Industry / John Jaeger / Cattle grazing dormant native range (< 7% crude protein; CP) require supplementation of additional protein to sustain body weight (BW) and body condition score (BCS). Daily delivery of these supplements is an economic burden to cattle producers faced with challenging economic circumstances. Supplementing cows infrequently (as little as once/week) has produced equivalent BW and BCS changes compared to daily delivery. Dried distiller’s grains with solubles (DDGS) provides more ruminally-undegradable protein (RUP; 50-60%) compared to traditional oilseed-meal supplements (i.e. soybean meal) that are >50% ruminally-degradable protein (RDP). Therefore, our objective was to evaluate the effects of supplementation frequency on performance, reproductive success, eating behavior, and subsequent calf performance of spring-calving cows supplemented with DDGS. No differences in ending BW (P = 0.69) and BCS (P = 0.49), or changes in BW and BCS over the supplementation period (P = 0.82 and 0.70, respectively) were observed among cows supplemented every d, every 3 d, or every 6 d. Calf BW at birth, weaning weight (WW), and average daily gain (ADG) were similar among treatments (P = 0.19, 0.12, and 0.10, respectively). First-service conception rate (FSCR) and final pregnancy rate (PR) were also not affected by supplementation frequency (P = 0.62 and 0.76, respectively). The development of replacement heifers is a large expense for cow-calf producers. Improved breeding and heifer development strategies aimed at ensuring the success of replacement females have been developed but reproductive failure still remains a problem. The stress associated with breeding and handling procedures may decrease reproductive success. Therefore, the objective was to determine if intramuscular administration of flunixin meglumine (1.1 mg/kg BW) 14 days post-breeding would improve FSCR and PR in non-transported replacement heifers. Under the conditions of our study, flunixin meglumine did not improve (P = 0.87) first service conception rate above that of control heifers (41.2% and 42.3%, respectively). Final pregnancy rate also was not different between treatments and averaged 81.8% (P = 0.40).

The aim of the work was to evaluate the milk production and fertility of the herd of Czech piebald cattle and to express the economic impact of the use of various breeding bulls used for breeding. The results of milk yield and insemination were evaluated in the years 2017 - 2018 for the last closed lactation sequence in the groups according to the order of lactation (1st lactation, 2nd lactation, 3rd lactation, 4th and next lactation). The indicators were evaluated for the three most commonly used breeding bulls. The average efficiency by the lactation sequence was in the 1st lactation 5143 kilogrammes of milk (P 0.001), the 2nd lactation 6520 kilogrammes of milk (P 0.01), the 3rd lactation 8186 kilogrammes of milk (P 0.001) and in the 4th and next lactation 7855 kilogrammes of milk. The efficiency of the whole herd was 6856 kilogrammes of milk contains 4.09% of fat and 3.46% of proteins. The avarige age at the first calving was 945 days, the length of the herd´s interval was 416 days, the insemination interval was 93 days and the service period was 129 days. The success rate of the 1st insemination in 2017 was 75%, in 2018 74%. The success rate of all insemination was 69% in both years. The costs of insemination of the whole herd with using all bulls in 2017 was 618 CZK and in 2018 was 577 CZK. Was found economic difference in using individual breeding bulls included in reprodudtion in a given herd.