The influence of the stage of lactation on the composition and properties of milk /

"January 10, 1913."

Stylosanthes guianensis cv. BRS Bela managed as organic fodder bank for supplementation of lactation crossbred cows in the Cerrado.

2016

A baseline projection of methane emissions by the Brazilian beef sector: preliminary results .

2007

Influence of lactation stages and rain periods on subclinical mastitis in meat producing ewes.

Mastitis negatively influences the survival and weight gain of ovines for meat production. The purpose of this study was to investigate, in sheep for meat production, the occurrence of subclinical mastitis in ewes at the end of lactation and beginning of the consecutive lactation and to assess the composition and cellular characteristics of milk as a function of different rainfall indices. Mammary halves (821) of Santa Ines (479) and Morada Nova (342) ewes were examined. Milk samples were collected in two different moments of lactation: at weaning and postpartum of the consecutive lactation. Sample collection periods were called ?dry? or ?rainy? according to the rainfall index in the month immediately before the month of collection. The occurrence of subclinical mastitis at weaning in the Santa Ines and Morada Nova ewes were 16.4 and 12.6% in the dry period, and 17.7 and 23.5% in the rainy period, respectively. In the consecutive lactation period, the occurrences were 26.7 and 27.7% in the dry period and 41.8 and 39.1% in the rainy period, for the Santa Ines and Morada Nova ewes, respectively. Postpartum stage was critical for the occurrence of subclinical mastitis, as compared to that at the end of the previous lactation. Occurrence of the disease negatively influenced the SCC in the milk at the beginning of lactation and changed its composition, mainly in the rainiest periods, probably due to a difficulty in maintaining hygiene in the environment where the animals remained.

Curvas de lactação em rebanhos da raça holandesa no estado de Minas Gerais. Escolha do modelo de melhor ajuste

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Neurobehavioral, reflexological and physical development of Wistar rat offspring exposed to ayahuasca during pregnancy and lactation

Ayahuasca is a hallucinogenic beverage prepared by the decoction of plants native to the Amazon Basin region. The beverage has been used throughout the world by members of some syncretic religious movements. Despite the recent legalization of ayahuasca in Brazil for religious purposes, there is little pre-clinical and clinical information attesting to its safety, particularly in relation to the use during pregnancy. The aim of the current work was to determine the effects of perinatal exposure to ayahuasca (from the 6th day of pregnancy to the 10th day of lactation) on physical, reflexology and neurobehavioral parameters of the Wistar rat offspring. The offspring showed no statistically significant changes in the physical and reflexology parameters evaluated. However, in adult rats, perinatally exposed to ayahuasca, an increase in frequency of entries in open arms in elevated plus-maze test, a decrease in total time of interaction in social interaction test, a decrease in time of latency for the animal to start swimming and a decrease of the minimum convulsant dose induced by pentylenetetrazol were observed. In conclusion, our results showed that the use of ayahuasca by mothers during pregnancy and lactation reduced the general anxiety and social motivation of the rat offspring. Besides, it promoted a higher sensitivity for initiation and spread of seizure activity.

Histometric Study of Alveolar Bone in Rats Submitted to Ethanol During Lactation

The present work studied the adverse effects of maternal exposure of rats to alcohol during lactation, on the development of their offspring. Histometric evaluation by karyometry and of the alveolar bone at the level of the first upper molar of the sucking was perfomed. Two groups of animals, one coming from mothers exposed to drinking water containing 20% ethanol during the total lactation period and the other of controls coming from mothers receiving only alcohol-free drinking water during this period. On the 21 first day of lactation the young of each group were aleatorily selected and following anesthesia, their heads severed; after histological treatment, serial 6 mu m sections on the frontal plane at the molar level, stained with hematoxilin and eosin, were obtained. The experimental results produced, suggest that sucking from ethanol-treated mothers, show retarded post-natal growth, their alveolar bones presenting scarce, little calcified trabeculae, and a more abundant bone marrow compared to controls.

Behavioral effects of acute stimulation of kappa-opioid receptors during lactation

The behavioral effects of the K-opioid receptor agonist U69593 were examined in lactating rats. On day 5 of lactation, animals were treated with 0.1 mg/kg of U69593 to determine whether it influences general activity and maternal latencies toward pups. Because little attention has been given to the possibility that pre-mating treatment with morphine may modulate the response to K-opioid receptor stimulation, another group of animals was submitted to the same acute challenge after abrupt withdrawal from repeated treatment with morphine sulfate during the pre-mating period (5 mg/kg on alternate days for a total of five doses). Acute F;opioid stimulation reduced total locomotion, rearing frequency, and time spent self-grooming and increased immobility duration. These K agonist effects were not observed in animals pretreated with morphine. Similarly, latencies to retrieve pups were longer only in animals pretreated with saline and challenged acutely with U69593. None of these effects were observed in morphine sulfate-pretreated animals. The present results suggest that pre-mating repeated exposure to morphine produces a tolerance-like effect on behavioral responses to low-dose K-opioid receptor stimulation in active reproductive females. (c) 2008 Elsevier Inc. All rights reserved.

Effects of intramammary infection on whey proteinograms of sheep during lactation

The study aimed to identify potential biomarkers of mammary gland infection in Santa Inês sheep. Commercial flocks of sheep provided the same hygiene, sanitary, and nutritional management under semi-intensive production systems were monitored during the lactation stage-and assessed 15, 30, 60, and 90 days after delivery (through the end of lactation and weaning). The California Mastitis Test (CMT) was performed on the mammary glands. Milk was collected for bacterial examination and protein analysis. Bacterial culture and biochemical characterization of the samples were performed. Forty-two milk samples from healthy glands (negative CMT and bacterial testing) and 43 milk samples from infected glands (positive CMT and bacterial testing) taken at the predefined time points were assessed. A rennin solution was used to obtain the whey. The proteins analysis was performed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), which allowed for the quantification of nine whey proteins produced in healthy glands: serum albumin, lactoferrin, IgA, IgG heavy-chain (IgG HC), IgG light-chain (IgG LC), total IgG (IgG HC + IgG LC), α-lactalbumin, β-lactoglobulin, protein with MW 15.000 Da, protein with MW 29.000 Da and eleven whey proteins secreted by infected glands, including haptoglobin and α-1-acid glycoprotein. A comparison of whey proteins between healthy and infected glands showed increases (P<0.05) in the secreted and total contents of all proteins, except for IgG LC and α-lactoalbumin. The most significant changes were observed in α-1-acid glycoprotein, lactoferrin and haptoglobin, which showed three-, five-, and seven-fold increases in secretion, respectively. This study showed that haptoglobin, α-1-acid glycoprotein, lactoferrin, albumin, and the IgA and IgG immunoglobulins may serve as potential biomarkers for mammary gland infection in sheep.

Spreading depression is facilitated in adult rats previously submitted to short episodes of malnutrition during the lactation period

Lactating rat dams were submitted to short episodes (1, 2 or 3 weeks) of nutritional restriction by receiving the "regional basic diet" (RBD, with 8% protein) of low-income human populations of Northeast Brazil. Their pups were then studied regarding the developmental effects on body and brain weights. When the rats reached adulthood, cortical susceptibility to the phenomenon of spreading depression (SD) was evaluated by performing electrophysiological recordings on the surface of the cerebral cortex. SD was elicited at 20-min intervals by applying 2% KCl for 1 min to a site on the frontal cortex and its occurrence was monitored at 2 sites in the parietal region by recording the electrocorticogram and the slow potential change of SD. When compared to control rats fed a commercial diet with 23% protein, early malnourished rats showed deficits in body and brain weights (10% to 60% and 3% to 15%, respectively), as well as increases in velocity of SD propagation (10% to 20%). These effects were directly related to the duration of maternal dietary restriction, with pups malnourished for 2 or 3 weeks presenting more intense weight and SD changes than those malnourished for 1 week. The effects of 1-week restrictions on SD were less evident in the pups malnourished during the second week of lactation and were more evident in pups receiving the RBD during the third week. The results indicate that short episodes of early malnutrition during the suckling period can affect body and brain development, as well as the cortical susceptibility to SD during adulthood. The data also suggest that the third week of lactation is the period during which the brain is most sensitive to malnutrition, concerning the effects on SD

Free and total GMP (glycomacropeptide) contents of milk during bovine lactation

Individual milk samples taken every two weeks from parturition to the end of lactation from 34 animals of three different herds and breeds were analyzed for free-GMP. A milk pool of each herd was analyzed for free and total GMP (released from k-casein by the action of rennin) and the data were correlated with sanitary conditions of animal and udder, phase of lactation and milk production. Most udder problems were concentrated near parturition, with few and spaced occurrences of clinical mastitis. The Californian Mastitis Test (CMT) results showed oscillations compatible with the phases of lactation period and environmental conditions. The widest variations in free-GMP occurred as a function of lactation period and as a consequence of clinical or subclinical mastitis. Higher levels were observed at the beginning of lactation (5.87mg L-1 of sialic acid), becoming normal with mean values of about 3.30mg L-1 at the end of the second month, and increasing again during the final third of lactation. On average, the same trends were observed for total GMP released by commercial rennet, beginning with slightly high values (35.59mg L-1), becoming normal by the sixth month with values close to 27.15mg L-1, and rising gradually up to the end of lactation, with 58.35mg L-1 of sialic acid. These results prove to be useful for the correct interpretation of tests applied to milk selection with respect to proteolytic status or even to restrain frauds by the addition of whey to milk.

Perceptions of intergroup bias : the roles of social projection and meta-stereotypes

Underlying intergroup perceptions include processes of social projection (perceiving personal traitslbeliefs in others, see Krueger 1998) and meta-stereotyping (thinking about other groups' perceptions of one's own group, see Vorauer et aI., 1998). Two studies were conducted to investigate social projection and meta-stereotypes in the domain of White-Black racial relations. Study 1, a correlational study, examined the social projection of prejudice and 'prejudiced' meta-stereotypes among Whites. Results revealed that (a) Whites socially projected their intergroup attitudes onto other Whites (and Blacks) [i.e., Whites higher in prejudice against Blacks believed a large percentage of Whites (Blacks) are prejudiced against Blacks (Whites), whereas Whites low in prejudice believed a smaller percentage of Whites (Blacks) are prejudiced]; (b) Whites held the meta:..stereotype that their group (Whites) is viewed by Blacks to be prejudiced; and (c) prejudiced meta-stereotypes may be formed through the social projection of intergroup attitudes (result of path-model tests). Further, several correlates of social projection and meta-stereotypes were identified, including the finding that feeling negatively stereotyped by an outgroup predicted outgroup avoidance through heightened intergroup anxiety. Study 2 replicated and extended these findings, investigating the social projection of ingroup favouritism and meta- and other-stereotypes about ingroup favouritism. These processes were examined experimentally using an anticipated intergroup contact paradigm. The goal was to understand the experimental conditions under which people would display the strongest social projection of intergroup attitudes, and when experimentally induced meta-stereotypes (vs. other-stereotypes; beliefs about the group 11 preferences of one's outgroup) would be most damaging to intergroup contact. White participants were randomly assigned to one of six conditions and received (alleged) feedback from a previously completed computer-based test. Depending on condition, this information suggested that: (a) the participant favoured Whites over Blacks; (b) previous White participants favoured Whites over Blacks; (c) the participant's Black partner favoured Blacks over Whites; (d) previous Black participants favoured Blacks over Whites; (e) the participant's Black partner viewed the participant to favour Whites over Blacks; or (£) Black participants previously participating viewed Whites to favour Whites over Blacks. In a defensive reaction, Whites exhibited enhanced social projection of personal intergroup attitudes onto their ingroup under experimental manipulations characterized by self-concept threat (i.e., when the computer revealed that the participant favoured the ingroup or was viewed to favour the ingroup). Manipulated meta- and otherstereotype information that introduced intergroup contact threat, on the other hand, each exerted a strong negative impact on intergroup contact expectations (e.g., anxiety). Personal meta-stereotype manipulations (i.e., when the participant was informed that her/ his partner thinks s/he favours the ingroup) exerted an especially negative impact on intergroup behaviour, evidenced by increased avoidance of the upcoming interracial interaction. In contrast, personal self-stereotype manipulations (i.e., computer revealed that one favoured the ingroup) ironically improved upcoming intergroup contact expectations and intentions, likely due to an attempt to reduce the discomfort of holding negative intergroup attitudes. Implications and directions for future research are considered.

Study of individual lactation patterns of Iranian dairy buffaloes

The aims of the current study were 1) to investigate the effects of some environmental factors on lactation curve traits (LCTs) including initial milk yield (A), peak yield (PY), days to attain peak yield (PD), inclining- and declining slope of lactation (B and C, respectively), persistency (Per), and 240-d milk yield, and 2) to estimate pairwise phenotypic correlations between these traits in two Iranian buffalo ecotypes (Khuzestani and Azeri buffaloes). The dataset consisted of 15396 and 9283 lactations from 6632 Khuzestani and 3558 Azeri buffaloes, respectively (collected during 1992–2009). The results revealed that almost all of the factors had significant effects on the majority of the LCTs, whereby age group, parity and season of calving had greater influence on 240-d milk yield and PY than the other LCTs in both of the ecotypes. These effects were more apparent in Khuzestani buffaloes than in Azeri buffaloes. In the Khuzestani ecotype, the LCTs were significantly correlated with each other. However, in the Azeri ecotype the 240-d milk yield showed no significant relationship with parameters B, PD and Per. In conclusion, the studied factors play an important role in determining both the shape of the lactation curve and the overal performance of Iranian dairy buffaloes.

The use of early lactation milk protein content to predict subsequent fertility performance and likelihood of culling, in commercial dairy cows

A dataset of 1,846,990 completed lactation record,; was created Using milk recording data from 8,967 commercial dairy farms in the United Kingdom over a five year period. Herd-specific lactation curves describing levels of milk, Cat and protein by lactation number and month of calving were generated for each farm. The actual yield of milk and protein proportion at the first milk recording of individual cow lactations were compared with the levels taken from the lactation curves. Logistic regression analysis showed that cows production milk with a lower percentage of protein than average had a significantly lower probability of being in-calf at 100 days post calving and it significantly higher probability of being culled at the end of lactation. The culling rates derived from the studied database demonstrate the current high wastage rate of commercial dairy cows. Well of this wastage is due to involuntary culling as a result of reproductive failure.