A computerized dairy herd simulation was developed to evaluate the economic impact of changing length of lactation relative to length of dry period in a dairy herd. It created weekly production for individual cows in a typical herd. Cows were dried off early if they were producing below a designated daily milk yield. They were replaced with fresh cows to produce more daily milk and increase profit while maintaining a constant number of cows in milk (98 to 102). A two by four factorial of dry off strategies was designed using rates of lactation decline of 6% and 8% and early dry off at 8, 13, 18, and 23 kg. Cows producing less than this for 2 wk consecutively were dried off. There were 100 cows in each herd and each of the eight scenarios was run 10 times (10 herds) for 80 herds total. Dry cow groups at 8, 13, 18, and 23 kg dry off were 14, 17, 23, and 32% of total herds, respectively. Average daily milk (kg) increased for the four dry kg: 30.4, 31.2, 32.3, and 33.7 kg/d per milking cow, whereas RHA decreased. Three different milk-feed income scenarios, (+20%, average, -20%) were combined with three dry cow costs, (+20%, average, and -20%). Nine combinations were analyzed statistically at each rate of decline. Net cash income changed $3561, $1571, and $-3051 from 8 to 13 to 18 to 23 kg dry kg under a normal economic situation. Net farm income under the same scenario changed $3170, $2945, and $-1154. Under the best economic situation, net cash income increased with each successive dry kg, $5086, $4248, and $921. Net farm income also increased by $4695, $5621, and $2819. Net cash income and net farm income were largest at 13 and 18 kg when milk-feed income was low and dry cow cost was high, the worst economy scenario. Only in the most optimistic economic situations does it appear practical for a dairy business to adopt early dry off beyond 13 kg/d per cow given the small gains and the yearly variability. Strategies of dry off at larger dry kg, although not greatly profitable, nevertheless were not extremely unprofitable either. / Master of Science

Introduktion: Att dia är ett medfött beteende, forskning påvisar stora hälsomässiga och ekonomiska fördelar med amning. Att skydda, stödja och främja amning är en folkhälsofråga. Distriktssköterskans arbete ska vara hälsofrämjande. Syfte: Att beskriva vilket amningsstöd ammande föräldrar uttrycker behov av. Metod: En kvalitativ, systematisk litteraturstudie med induktiv ansats som bygger sitt resultat på 11 vetenskapliga artiklar. Resultat: Föräldrarna behövde tidigt amningsstöd som fortsatte under hela amningsperioden. De önskade få ett lugnt och empatiskt bemötande från vårdpersonal med erfarenhet och kunskap om amning. Individuellt stöd gav styrka, beslutsamhet och självförtroende. De önskade samstämmig information som följde rådande rekommendationer. Föräldrar hade behov av praktisk amningsrådgivning, särskilt vid amningsdebut. De behövde positiv uppmuntran och stöd för sin upplevda självtillit för att lyckas amma. Konklusion: Vårdpersonal kan stödja nyblivna föräldrar genom att vägleda föräldern i en första lyckad amning; visa amning som fungerar i mötet med andra föräldrar i amningsgrupp, samt genom positiv respons och en uppmuntran som lär föräldern att se att amningen fungerar. Allt detta leder till förhöjd upplevd självtillit som i sin tur ökar sannolikheten att föräldern lyckas amma. / Introduction: Suckling is an innate behavior, and research shows great advantages in breastfeeding. To protect, support and advance breastfeeding is a public health issue. Public health care should be the district nurse’s main focus. Purpose: To describe what breastfeeding parents express a need for regarding lactation support. Method: A qualitative systematic literature review with inductive approach which is based on 11 scientific papers. Result: The parents needed early breastfeeding support that lasted the whole breastfeeding period. They needed support in a calm and empathetic manner from experienced, knowledgeable healthcare staff. Parents needed individual support that gave strength, determination, and confidence. They wished for unanimous information that was supported by current recommendations. The parents needed practical breastfeeding counseling, especially at the beginning. They needed encouragement and support for their perceived self-efficacy to succeed. Conclusion: Health care staff can give new parents guidance to an early successful breastfeeding experience; show functioning breastfeeding through breastfeeding groups and give positive response while giving encouragement that leads the parent to see that their own breastfeeding is successful and thereby gain increased self-efficacy.

While they are pregnant and rearing pups, bats continue to leave their roosts to forage for food. Many bats use echolocation vocalizations as part of this process. Other mammalian species including primates experience changes in vocal characteristics during pregnancy and lactation. As echolocation is a vital tool for spatial navigation and prey detection in most bats, investigating echolocation characteristics during pregnancy through lactation may provide new insight into how reproduction, pregnancy and pup rearing influence vocalizations. We measured changes in mass and recorded echolocation calls of pregnant (n = 21) and non-pregnant (n = 2) female wild-caught big brown bats (Eptesicus fuscus) released by hand into roost emergence-like flight. Recording began ~15 days prepartum and ended when the last bat reached 34 days postpartum, when pups were expected to be weaned. Analyses were completed using MATLAB and R, primarily with repeated measures ANOVAs focused on echolocation calls present in the ~562 ms before and ~562 ms after take-off. Based on vocal changes experienced by humans during pregnancy and post-birth, correlations found between bat echolocation call characteristics and the effects of differences in mass on bat echolocation, we predicted that female bats in late-stage pregnancy would emit calls of shorter duration, longer pulse interval, narrower bandwidth, and lower centroid frequency compared to calls emitted by the same bat post-parturition and compared to non-pregnant bats, while source level remained unchanged. We found that pulse interval and source level did not change while pregnant/lactating or control bats were in flight, and that increases in call duration and decreases in centroid frequency and bandwidth in flight began in pregnancy and continued through the lactation period while remaining unchanged for the control bats. / Thesis / Master of Science (MSc) / The goals of this study were to see if big brown bats change the way that they echolocate while they are pregnant and/or nursing pups, and what changes occur. We did this by recording the vocal sounds bats made while they were pregnant and after they had given birth, and looking to see if there were any changes in the duration of echolocation calls, the time between individual sounds, the range of sound frequencies in each call, the central sound frequency in each call, and each call’s sound pressure level over this time and compared to non-pregnant/nursing female big brown bats. We found that echolocation call duration increases over pregnancy and nursing pups, while frequency range and the centre frequency decreases.

No description available.

No description available.

A series of studies were conducted to evaluate effects of lactation, exercise, and anti-folate drugs on folate status in the horse, and the bioavailability of supplement and feed folate in the horse. In the first study, mares and foals had adequate plasma folate, RBC folate, and plasma homocysteine concentrations during 6 mo of lactation and growth. Therefore, mares and foals maintained on quality grass/legume pastures and offered a pasture supplement did not require additional folate supplementation to maintain folate status during lactation and growth. In the second study, 25 mg of oral folic acid (FA) supplemented 5 times/wk to 11 mature horses engaged in routine submaximal exercise did not improve folate status, submaximal athletic performance, or combat the increase in oxidative stress during the 12 wk supplementation period compared to 11 horses not given supplemental folate. The common practice of supplementing horses with oral FA in vitamin supplements appears to be of little benefit to horses engaged in routine submaximal exercise. In the third study, daily oral administration of pyrimethamine (PYR) and sulfadiazine (SDZ) for 9 wk followed by 6 wk of coadministration of either Peptidoglycan or FA was associated with a decline in folate status resulting in moderate hyperhomocysteinemia, but not clinical signs of anemia. Peptidoglycan as a source of formylated folate and FA were not effective in improving folate status in horses coadministered PYR and SDZ, two anti-folate drugs commonly administered in equine veterinary practice. The last study assessed the bioavailability of oral and i.v. 5-methyltetrahydrofolate (5-mTHF), 5-formyltetrahydrofolate (5-fTHF), or FA, and the bioavailability of folate from concentrates fed to horses. The minimum efficiency of absorption for supplemental FA was 11 %. The low bioavailability of FA indicates a need for further research on the potential benefits of alternative sources of folate, including 5-fTHF, on increasing folate status in the horse. / Ph. D.

Increased milking frequency (IMF) in early lactation is a time and cost-effective farm management practice to enhance profit in the dairy industry. The process involves milking cows more often in early lactation alone. On farms that milk twice daily (2X), early lactation cows are milked four times daily (4X) for 21 d postpartum. Cows produce significantly more milk during this timeframe and continue to have increased milk yield (MY) when returned to 2X milking for the remainder of lactation. The objective of this dissertation was to discover the physiological processes of early lactation IMF that cause increased MY throughout lactation. All studies involved unilateral frequent milking (UFM) with 2X and 4X udder halves for 21 d in early lactation. The first study manipulated milking interval (MI), or the time between milkings, during early lactation IMF. Cows were either milked on an even MI every 6 h or unevenly on a 9:3:9:3 h MI. Unevenly milked cows produced more milk on the final day of 4X treatment, but there was no significant difference in the increased MY carry-over effect between MI groups. Therefore, farmers can utilize any MI that fits their schedule and still achieve significantly enhanced profits. The second study aimed to infer the metabolic mechanisms of early lactation IMF that increase MY by comparing it to bovine somatotropin (bST). Cows that underwent early lactation IMF received bST at 80 DIM. Both IMF and bST treatments significantly enhanced MY, but there was no interaction or synergistic effect between treatments. We surmised that IMF and bST cause increased MY through different metabolic mechanisms since IMF functions locally and bST operates systemically. The final study analyzed mammary tissue from 2X and 4X udder halves on the final day of UFM treatment. The mechanism in which IMF enhanced MY involved increased protein levels of signal transducer and activator of transcription (STAT5), activated and total protein kinase B (Akt), and total extracellular signal-regulated kinase 1 and 2 (ERK1/2) and reduced protein levels of total mammalian target of rapamycin (mTOR) and total mitogen activated protein kinase (MAPK) in 4X udder halves compared to 2X. / Doctor of Philosophy / Increased milking frequency in early lactation is the process of milking cows more often for the first 3 weeks after calving. Cows not only produce more milk during this timeframe but continue to have elevated milk yield throughout lactation. This phenomenon is called the increased milk yield carry-over effect. This dissertation aimed to further enhance the increased milk yield carry-over effect of early lactation increased milking frequency. All studies utilized unilateral frequent milking with left udder halves milked twice daily and right udder halves milked four-times daily. The first study compared even and uneven milking intervals alongside early lactation increased milking frequency. The right udder halves of the even groups were milked every 6 hours. Cows in the uneven milking interval group were milked on a 9:3:9:3 hour interval. The uneven milking interval group produced more milk than even milking interval group on the final day of milking frequency treatment. However, there was no difference in milk yield between groups at any other time point. All cows had an increased milk yield carry-over effect throughout 300 days of lactation. In the second study, cows received bovine somatotropin in mid-lactation to observe possible synergistic effects in enhancing milk yield after early lactation increased milking frequency. Both the bovine somatotropin and increased milking frequency increased milk yield, but there was no synergistic effect when the two treatments were combined. The final study analyzed proteins within mammary tissue after 3 weeks of unilateral frequent milking. Udder halves milked four-times daily had significantly elevated activated and total STAT5, activated and total Akt, and total ERK1/2. Udder halves milked twice daily had elevated total MAPK and total mTOR. These findings helped to understand the metabolic functioning of increased milking frequency in early lactation that causes a persistent increase in milk yield throughout lactation.

Mature human milk composition was determined from monthly samples collected from five, healthy, Caucasian, lactating women. A 72-hour dietary record was kept monthly from the twelfth week of pregnancy to the sixth month postpartum. Nutrient content of milk samples was similar to values reported in the literature. Calcium and zinc concentrations of human milk decreased significantly during the five month study. Moisture, energy, total lipids, protein, and magnesium levels remained fairly constant over the course of lactation. Dietary intake during pregnancy was not significantly correlated with nutrient concentration in human milk. For dietary intake during lactation, a significant correlation was observed between caloric intake and energy content of human milk for the second month of lactation. A significant correlation was observed between protein intake and protein content in the milk for the sixth month of lactation. Zinc concentration was significantly correlated with dietary intake during the fourth month of lactation. No other significant correlation was observed between nutrient content of human milk and dietary intake during the lactation period. / M.S.

Lactating women have an increased requirement for folate which contributes to their risk for suboptimal folate status. Although milk folate secretion appears to be maintained independent of folate intake and maternal folate status, studies with animal species have demonstrated a relationship between iron deficiency and impaired milk folate secretion. Objectives of this study were to monitor the folate status of lactating women and to examine the relationship among folate intake, dietary iron, folate status, iron status and milk folate. Seven-day dietary records, milk samples, and blood samples were collected monthly for four months from five lactating women. Dietary iron and folate was analyzed. Milk folate, serum ferritin, serum folate, and red blood cell (rbc) folate concentrations were measured. Mean folate and iron intakes were 495 ± l05μg/d and 24 ± 4 mg/d, respectively. All women had normal rbc folate and serum ferritin values during the study. Milk folate increased (p=.06) from 35± 10 μg/L in month one to 69 ± 30 μg/L in month three. Dietary and rbc folate were not significantly correlated with milk folate. There was a significant positive correlation between milk folate and serum folate (r = .48, p= .04) and between milk folate and iron intake (r=.63, p=.003). Results indicate that the folate intake in this population of lactating women was sufficient to maintain adequate folate stores. Results also suggest a relationship between iron intake and milk folate. Research is needed to determine dietary requirements during lactation and to investigate the relationship between dietary iron and milk folate. / Master of Science

The present study was designed to measure levels of oxytocic activity in the blood of cows before, during, and after physical stimulation to the teats and udder. It was also designed to determine the relationship between these levels and intramammary pressure. Knowledge in both these areas has been lacking up to the present. Some information in these areas was obtained as a result of this study. It was found that a wide variation existed in the levels of oxytocic activity between cows. In most cows, a bulk of oxytocic activity was detected in the interval of one to four minutes after stimulation began. The activity rapidly declined to low levels, with some exceptions, between the third and fourth minute post-stimulation. This information indicates that no specific changes need to be made in the present milking procedures. / Master of Science