Effect of Red and White Clover Added to a Rye Grass-Based Diet on Intake, Fibre Digestion and Methane Release of Dairy Cows

Forage legumes like white and red clover are widely grown in association with grass, with the intention to improve the quality of grass-based diets. However little is known about the effect of either white or red clover added to a grass-based diet on methane release, and existing studies are not conclusive. The objective of this study, applying the respiratory chamber technique, was to determine the effect of red and white clover added to a rye grass-based diet on intake, fibre digestion and methane release of dairy cows

Effects of a latency period between pre-stimulation and teat cup attachment and periodic vacuum reduction on milking characteristics and teat condition in dairy cows

The goal of the present study was to examine the suitability of a short pre-stimulation (P) for 15s followed by a latency period (L) of 30s before cluster attachment for machine milking. In addition we tested the effect of a periodic reduction of the vacuum under the teat (VR) during the massage phase from 43kPa to 12-15kPa on milking characteristics and teat tissue condition. The study was carried out in 9 cows in a cross-over design. Animals were milked twice daily, and each of the 4 treatment combinations was used for six subsequent milkings (P+L vs. continuous P, and standard pulsation vs. VR, respectively). Milk flow was recorded during all experimental milkings. Longitudinal ultrasound cross sections of the teat were performed by B-mode ultrasound after the last milking of each treatment at 0, 5, and 15min after the end of milking, respectively. None of the evaluated milking characteristics (total milk yield, main milking time, peak flow rate, average milk flow) differed between treatments. Teat measures as obtained by ultrasound cross sections showed no significant difference if individual treatments were compared at the three time points individually. However, teat wall thickness (TWT) tended to be smaller in VR vs. non-VR treatments at 5min after milking (P=0·05). In conclusion, teat preparation consisting of a short stimulation followed by a latency period represents a similarly efficient pre-stimulation as a continuous pre-stimulation. VR seems to reduce the load on the teat tissue during milking and thus reduces the development of oedema and hence a less pronounced increase of TWT while milking characteristics are similar with or without V

Continuous milking of dairy cows disrupts timing of peak IgG concentration appearance in mammary secretions

The length of the dry period in commercial dairy production is under close scrutiny. While the main concern is the composition and volume of milk produced, the evaluation of colostrum quality under these new paradigms has suggested a decline in IgG concentrations, while some reports indicate no change. Colostrum quality has been defined as an adequate concentration (>50mg/ml) of immunoglobulin in the secretions to provide the newborn with maximal disease resistance. We investigated the appearance of IgG in mammary pre- and post partum secretions in cows without a dry period (continuously milked, Dry0) and compared the secretions with cows that experienced a dry period of 60d (Dry60). Blood was collected during the experimental period and plasma analysed for progesterone (P4) and prolactin (Prl). Approximately −6d relative to parturition, the Dry0 animals exhibited increased concentration of IgG in their secretions to an average of ∼35mg/ml that remained rather constant through subsequent pregnancy and following parturition. Dry0 cows were producing an average IgG concentration in parturition colostrum of 44·2±17·6mg/ml that was not different than that of controls (66·86±16·8mg/ml). However, Dry0 cows exhibited high variation, different peak times (day) of IgG concentration including times that occurred both pre and post parturition. IgG mass of the Dry0 cows remained rather constant pre- and post partum and did not show the same declining mass following parturition that was shown for the Dry60 cows. The change in plasma P4 and Prl were shown to have no timing effect on colostrum IgG concentratio

Thyroid Hormone Therapy for Older Adults with Subclinical Hypothyroidism.

BACKGROUND: The use of levothyroxine to treat subclinical hypothyroidism is controversial. We aimed to determine whether levothyroxine provided clinical benefits in older persons with this condition. METHODS: We conducted a double-blind, randomized, placebo-controlled, parallel-group trial involving 737 adults who were at least 65 years of age and who had persisting subclinical hypothyroidism (thyrotropin level, 4.60 to 19.99 mIU per liter; free thyroxine level within the reference range). A total of 368 patients were assigned to receive levothyroxine (at a starting dose of 50 μg daily, or 25 μg if the body weight was <50 kg or the patient had coronary heart disease), with dose adjustment according to the thyrotropin level; 369 patients were assigned to receive placebo with mock dose adjustment. The two primary outcomes were the change in the Hypothyroid Symptoms score and Tiredness score on a thyroid-related quality-of-life questionnaire at 1 year (range of each scale is 0 to 100, with higher scores indicating more symptoms or tiredness, respectively; minimum clinically important difference, 9 points). RESULTS: The mean age of the patients was 74.4 years, and 396 patients (53.7%) were women. The mean (±SD) thyrotropin level was 6.40±2.01 mIU per liter at baseline; at 1 year, this level had decreased to 5.48 mIU per liter in the placebo group, as compared with 3.63 mIU per liter in the levothyroxine group (P<0.001), at a median dose of 50 μg. We found no differences in the mean change at 1 year in the Hypothyroid Symptoms score (0.2±15.3 in the placebo group and 0.2±14.4 in the levothyroxine group; between-group difference, 0.0; 95% confidence interval [CI], -2.0 to 2.1) or the Tiredness score (3.2±17.7 and 3.8±18.4, respectively; between-group difference, 0.4; 95% CI, -2.1 to 2.9). No beneficial effects of levothyroxine were seen on secondary-outcome measures. There was no significant excess of serious adverse events prespecified as being of special interest. CONCLUSIONS: Levothyroxine provided no apparent benefits in older persons with subclinical hypothyroidism. (Funded by European Union FP7 and others; TRUST ClinicalTrials.gov number, NCT01660126 .)

Comparison of fresh and ensiled white and red clover added to ryegrass on energy and protein utilization of lactating cows

ISSN:1357-7298ISSN:0003-3561ISSN:1748-748

Preference of dairy cows for ryegrass, white clover and red clover, and its effects on nutrient supply and milk quality

Two experiments were conducted with 30 dairy cows each, to study the preference for fresh (Experiment 1) and ensiled (Experiment 2) ryegrass, white and red clover. Both experiments consisted of three choice diets with white or red clover or both, offered with ryegrass, and two diets with ryegrass mixed with white or red clover (40% clover). Cows consumed diets with 37.7% fresh white and 45.9% red clover, and no preference was observed when the cows were offered all three forages. By contrast, cows preferred white and red clover silage (73.0 and 69.2%, respectively) over ryegrass silage (of lower nutritive quality). When offered three forages, cows preferred white (59.8%) over red clover (17.5%) and ryegrass (22.7%). Choice diets resulted in diets similar (fresh forages) or higher in nutrient content and digestibility (silages). Treatments did not affect feed intake and performance. Choices compared to mixed diets with red clover silage were preferable regarding the fatty acid composition of the milk fat. Obviously, only large differences in nutrient and energy concentration facilitate preferences for clovers over ryegrass, which could, depending on clover type, be beneficial in terms of the milk's fatty acid composition

Metabolic status and oestrous cycle in dairy cows

A study with 40 multiparous high yielding dairy cows was conducted to investigate the influence of an induced negative energy balance (NEB) on reproductive performance. Energy restriction of 49% was performed for 3 weeks beginning on oestrous cycle day 12 of first oestrous cycle after day 85 post partum (pp). From day 20 to day 150 pp animals were monitored for ovary activity three times weekly using rectal palpation and transrectal ultrasound scanning and were inseminated around day 150 pp. Additionally, milk progesterone and milk hydrocortisone were analyzed twice a week. Body condition score and body weight as well as blood glucose, plasma nonesterified fatty acids and plasma β-hydroxybutyrate were recorded weekly. According to oestrous cycle activity before (Period 1 = natural energy deficiency), during (Period 2) and after (Period 3) induced energy restriction animals were assigned to the following groups: Delayed first ovulation until day 45 pp, normal oestrous cycle, prolonged oestrous cycle and shortened oestrous cycle. Sporadic significances, but no clear effect of the metabolic state on reproductive performance could be found during Periods 1 and 2. Service success and conception rate were also not influenced. Our results demonstrate a remarkable adaptation of reproductive activity to metabolic challenges. Animals were able to compensate natural NEB in Period 1 as well as induced NEB (Period 2) for preventing metabolic disorders and maintaining reproductive activity. Therefore dietary energy availability had no effect on reproductive performance at more than 85 days in milk in the present study. To understand reproductive failures in dairy cows focus should be laid on genetic disposition of high yielding individuals that cope successful with metabolic challenges