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1.
DNA Cell Biol ; 38(11): 1188-1196, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31603699

RESUMO

The mammary gland is an important organ for lactation in dairy goats. Mammary gland development and lactation functions are primarily regulated by natural hormones and certain crucial regulatory factors. Nedd4 family-interacting protein 1 (Ndfip1) can specifically bind to neural precursor cell-expressed, developmentally downregulated protein 4 (Nedd4) family members to participate in ubiquitination, which in turn regulates a range of biological processes in the body. However, the effects of Ndfip1 expression regulation at the post-transcriptional level on the development of mammary gland cells have not been previously reported. To study the regulation of Ndfip1 at post-transcriptional level, the overexpression and interference vectors of Ndfip1 were constructed, and co-transfected into the primary mammary gland epithelial cells cultured in vitro with miR-143 mimics and inhibitor. Dual luciferase reporter gene system, real-time quantitative polymerase chain reaction, western blotting, cholecystokinin octapeptide assays, and flow cytometry were used to identify their regulation and function. As a result, Ndfip1 was targeted and regulated by miR-143, which influences the development of mammary gland epithelial cells in dairy goats cultured in vitro. This study will lay an experimental foundation for further understanding the functions of Ndfip1 and miR-143.


Assuntos
Apoptose/genética , Células Epiteliais/fisiologia , Cabras , Lactação/genética , Glândulas Mamárias Animais/fisiologia , Proteínas de Membrana/genética , MicroRNAs/fisiologia , Animais , Células Cultivadas , Indústria de Laticínios , Células Epiteliais/metabolismo , Feminino , Regulação da Expressão Gênica , Cabras/genética , Cabras/metabolismo , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/metabolismo
2.
J Dairy Sci ; 102(11): 10606-10615, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31477309

RESUMO

The objective of this study was to evaluate the effects of 2 winter (December to April) housing systems on dairy cow hygiene scores, frostbite, teat condition, clinical mastitis, and activity and rumination across 3 winter seasons (2013, 2014, and 2015). Certified-organic cows (n = 268) were randomly assigned to 2 treatments (2 replicates per system): (1) outdoor straw pack (outdoor) or (2) 3-sided compost-bedded pack barn (indoor). Cows calved during 2 seasons (spring or fall) at the University of Minnesota West Central Research and Outreach Center, Morris, Minnesota, organic dairy. Organic wheat straw was used as bedding for the 2 outdoor straw packs, and bedding was maintained by farm management to keep cows dry and absorb manure throughout the winter. The compost-bedded pack barn (2 pens in the barn) was bedded with organic-approved sawdust, and the bedding material was stirred twice per day with a small chisel plow. Hygiene scores were recorded biweekly as cows exited the milking parlor. Incidence of clinical mastitis was recorded in a binary manner as treated (1) or not treated (0) at least once during a lactation. Frostbite incidence was collected monthly. Activity and rumination times (daily and 2-h periods) were monitored electronically using a neck collar sensor (HR-LD Tags, SCR Dairy, Netanya, Israel). Indoor cows had greater udder hygiene scores (1.75 vs. 1.46) and greater abdomen hygiene scores (1.79 vs. 1.43) compared with outdoor cows. Additionally, the indoor cows had greater upper and lower leg hygiene scores compared with outdoor cows. Incidence of clinical mastitis was greater for indoor cows compared with outdoor cows (27.1% vs. 15.1%, respectively). Frostbite incidence was not different between indoor (30.1%) and outdoor (17.5%) cows. Daily rumination was 509 min/d for indoor cows and 530 min/d for the outdoor cows. In summary, lactating cows housed outdoors on straw-bedded packs had cleaner udders and improved udder health compared with cows housed in a compost-bedded pack barn.


Assuntos
Doenças dos Bovinos/prevenção & controle , Indústria de Laticínios , Congelamento das Extremidades/veterinária , Abrigo para Animais , Glândulas Mamárias Animais/fisiologia , Ruminação Digestiva , Animais , Bovinos , Feminino , Congelamento das Extremidades/prevenção & controle , Higiene , Israel , Lactação , Leite , Minnesota , Estações do Ano
3.
Arch Anim Nutr ; 73(6): 457-471, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31454268

RESUMO

The aim of the study was to investigate if dietary alpha-ketoglutarate (AKG) supplementation may improve the performance of lactating sows and their suckling piglets. After farrowing, 24 lactating sows (Large White × Landrace) with similar body weight (BW) were assigned to the control and AKG groups based on parity, and their lactation diets were supplemented with 0.00 or 0.25% AKG, respectively. It was found that supplementing the diet of lactating sows with 0.25% AKG enhanced growth performance of the suckling piglets from d 7 to d 21 of the lactation period, improved villus height of ileum and tended (p = 0.085) to increase mean volumetric bone mineral density of femur in the weanling piglets. In the lactating sows, dietary supplementation of AKG decreased plasma urea level on d 14 of lactation, decreased plasma calcium (Ca) concentrations from d 7 to d 21 of lactation and increased lactose and Ca levels in ordinary milk. Thus, it was proposed that AKG supplementation stimulates the capacity for lactose synthesis and Ca uptake in the mammary gland, thereby altering the composition of the ordinary milk which might be associated with the enhanced performance of piglets during the suckling period. These findings could lead to a better application of AKG in lactating nutrition, and therefore, promoting pork production.


Assuntos
Aminoácidos/metabolismo , Animais Lactentes/crescimento & desenvolvimento , Ácidos Cetoglutáricos/metabolismo , Lactação/efeitos dos fármacos , Biossíntese de Proteínas , Sus scrofa/fisiologia , Aminoácidos/efeitos dos fármacos , Ração Animal/análise , Animais , Animais Lactentes/metabolismo , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Ácidos Cetoglutáricos/administração & dosagem , Glândulas Mamárias Animais/efeitos dos fármacos , Glândulas Mamárias Animais/fisiologia , Leite/química , Valor Nutritivo/efeitos dos fármacos , Biossíntese de Proteínas/efeitos dos fármacos , Sus scrofa/crescimento & desenvolvimento
4.
J Dairy Sci ; 102(10): 8648-8657, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351732

RESUMO

In dairy goats, very little is known about the effect of the 2 most important indirect indicators of udder health [somatic cell count (SCC) and total bacterial count (TBC)] on milk composition and cheese yield, and no information is available regarding the effects of lactose levels, pH, and NaCl content on the recovery of nutrients in the curd, cheese yield traits, and daily cheese yields. Because large differences exist among dairy species, conclusions from the most studied species (i.e., bovine) cannot be drawn for all types of dairy-producing animals. The aims of this study were to quantify, using milk samples from 560 dairy goats, the contemporary effects of a pool of udder health indirect indicators (lactose level, pH, SCC, TBC, and NaCl content) on the recovery of nutrients in the curd (%REC), cheese yield (%CY), and daily cheese yields (dCY). Cheese-making traits were analyzed using a mixed model, with parity, days in milk (DIM), lactose level, pH, SCC, TBC, and NaCl content as fixed effects, and farm, breed, glass tube, and animal as random effects. Results indicated that high levels of milk lactose were associated with reduced total solids recovery in the curd and lower cheese yields, because of the lower milk fat and protein contents in samples rich in lactose. Higher pH correlated with higher recovery of nutrients in the curd and higher cheese yield traits. These results may be explained by the positive correlation between pH and milk fat, protein, and casein in goat milk. High SCC were associated with higher recovery of solids and energy in the curd but lower recovery of protein. The higher cheese yield obtained from milk with high SCC was due to both increased recovery of lactose in the curd and water retention. Bacterial count proved to be the least important factor affecting cheese-making traits, but it decreased daily cheese yields, suggesting that, even if below the legal limits, TBC should be considered in order to monitor flock management and avoid economic losses. The effect of NaCl content on milk composition was linked with lower recovery of all nutrients in the curd during cheese-making. In addition, high milk NaCl content led to reductions in fresh cheese yield and cheese solids. The indirect indicators of the present study significantly affected the cheese-making process. Such information should be considered, to adjust the milk-to-cheese economic value and the milk payment system.


Assuntos
Queijo , Cabras , Glândulas Mamárias Animais/fisiologia , Leite , Valor Nutritivo , Animais , Caseínas/análise , Contagem de Células/veterinária , Feminino , Conteúdo Gastrointestinal , Lactose/análise , Leite/química , Leite/citologia , Leite/microbiologia , Paridade , Gravidez , Cloreto de Sódio/análise
5.
BMC Vet Res ; 15(1): 241, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296208

RESUMO

BACKGROUND: A major challenge in modern medicine and animal husbandry is the issue of antimicrobial resistance. One approach to solving this potential medical hazard is the selection of farm animals with less susceptibility to infectious diseases. Recent advances in functional genome analysis and quantitative genetics have opened the horizon to apply genetic marker information for efficiently identifying animals with preferential predisposition regarding health traits. The current study characterizes functional traits with a focus on udder health in dairy heifers. The animals were selected for having inherited alternative paternal haplotypes for a genomic region on Bos taurus chromosome (BTA) 18 genetically associated with divergent susceptibility to longevity and animal health, particularly mastitis. RESULTS: In the first weeks of lactation, the q heifers which had inherited the unfavorable (q) paternal haplotype displayed a significantly higher number of udder quarters with very low somatic cell count (< 10,000 cells / ml) compared to their paternal half-sib sisters with the favorable (Q) paternal haplotype. This might result in impaired mammary gland sentinel function towards invading pathogens. Furthermore, across the course of the first lactation, there was indication that q half-sib heifers showed higher somatic cell counts, a surrogate trait for udder health, in whole milkings compared to their paternal half-sib sisters with the favorable (Q) paternal haplotype. Moreover, heifers with the haplotype Q had a higher feed intake and higher milk yield compared to those with the q haplotype. Results of this study indicate that differences in milk production and calculated energy balance per se are not the main drivers of the genetically determined differences between the BTA18 Q and q groups of heifers. CONCLUSIONS: The paternally inherited haplotype from a targeted BTA18 genomic region affect somatic cell count in udder quarters during the early postpartum period and might also contribute to further aspects of animal's health and performance traits due to indirect effects on feed intake and metabolism.


Assuntos
Glândulas Mamárias Animais/fisiologia , Herança Paterna , Animais , Bovinos , Mapeamento Cromossômico , Ingestão de Alimentos/genética , Metabolismo Energético/genética , Feminino , Haplótipos/genética , Lactação/genética , Masculino , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/genética , Período Pós-Parto
6.
Animal ; 13(S1): s35-s41, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280741

RESUMO

Accumulating evidence supports that the hormone prolactin (PRL) is galactopoietic in dairy ruminants. Accordingly, the inhibition of PRL secretion by the dopamine agonists quinagolide and cabergoline causes a sharp decline in milk production and could be useful in several critical periods. First, PRL inhibition may reduce the incidence during the periparturient period of metabolic disorders caused by the abrupt increase in energy demand for milk production. Metabolic disturbances can be lessened by reducing milk output by milking once a day or incompletely in the first few days of lactation. The injection of cows with quinagolide for the first 4 days of lactation reduced milk production during the first week of lactation without any residual effects. Blood glucose and calcium concentrations were higher and ß-hydroxybutyric acid concentration was lower in the quinagolide-treated cows. Second, PRL inhibition may help sick or injured lactating cows, considering that they can fall into severe negative energy balance when they are unable to consume enough feed to support their milk production. This leads to a weakened immune system and increased susceptibility to diseases. When cows were subjected to feed restriction and were treated with quinagolide, the decrease in milk production was accelerated without any residual effects. The quinagolide-treated cows had higher glucose and lower ß-hydroxybutyric acid and non-esterified fatty acid concentrations than the control cows did. Third, PRL inhibition may facilitate drying-off in high-yielding cows, because they are often dried off while still producing significant quantities of milk, which delays mammary involution and increases risk of mastitis. Therefore, strategies that reduce milk production before drying-off and accelerate mammary gland involution could be an important management tool. In this context, inhibition of PRL was utilised to accelerate mammary gland dry-off. Quinagolide decreased milk production within the first day of treatment, and both quinagolide and cabergoline induced more rapid changes in several markers of mammary gland involution after drying-off. In addition, quinagolide improved the animals' resistance to intramammary infection. These results suggest that the inhibition of PRL could be a strategy for facilitating drying-off, reducing metabolic stress during the postpartum period, and alleviating acute nutritional stress during illness without compromising the overall productivity of dairy ruminants.


Assuntos
Bovinos/fisiologia , Metabolismo Energético , Lactação/fisiologia , Leite/metabolismo , Prolactina/antagonistas & inibidores , Ácido 3-Hidroxibutírico/sangue , Aminoquinolinas , Criação de Animais Domésticos , Animais , Cabergolina , Ácidos Graxos não Esterificados/sangue , Feminino , Glândulas Mamárias Animais/fisiologia , Prolactina/metabolismo
7.
Animal ; 13(S1): s20-s25, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280742

RESUMO

Mammary development takes place during the growing and gestation periods in swine but it also continues after farrowing. In fact, a significant proportion of mammary accretion occurs during lactation and is stimulated by suckling. After piglets are weaned, there is involution of the mammary glands and the process of mammogenesis starts again during the next parity. Suckling of a teat for the first 12 to 14 h after farrowing is not sufficient to maintain lactation, and mammary involution accompanied by alterations in gene transcription will take place. The involution process is reversible within 1 day postpartum but is not reversible if a mammary gland is unsuckled for 3 days. Mammary glands that undergo involution early in lactation do not show further involution in the post-weaning period. The action of a teat being suckled does not only affect mammary development in the ongoing lactation but it also impacts mammogenesis in the following lactation. Indeed, when a mammary gland is not suckled in first parity it has a diminished development and lower milk yield in second parity. Furthermore, it was shown that suckling of a teat for only the first 2 days postpartum in primiparous sows is sufficient to ensure optimal mammary development and milk yield from that teat in the next lactation. The behavior of nursing piglets in early lactation is also affected by whether or not a teat was previously used. Such knowledge on lactation biology is essential in order to develop the best adapted management strategies for the currently used hyperprolific sow lines and to optimize growth rate of their piglets. This review gives an update on the role of suckling for mammary development in lactating sows and on how it can affect management strategies of primiparous sows.


Assuntos
Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Leite/metabolismo , Suínos/fisiologia , Animais , Animais Lactentes , Feminino , Paridade , Estimulação Física , Gravidez , Desmame
8.
Animal ; 13(S1): s86-s93, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280744

RESUMO

Small ruminants not only differ on mammary gland anatomy, milk's properties and the amount of milk yielded comparable to those of dairy cattle, but also on the milking routine strategies and machine milking settings to maximize daily milk secretion. The udder compartment is proportionally larger in dairy sheep and goats, which requires modifications in the milking machine settings, milking procedures and allows the use of different milking strategies as they better tolerate extension of milking intervals. Depending on the breed, cisternal milk in goats varies from 70% to 90%, whereas in dairy sheep it varies from 50% to 78% of the total gland capacity. This explains why these species are commonly milked without pre-milking teat preparation, while in goats it is applied only in cases of high prevalence of intramammary infection in the herd. Recent French researchers observed that 40% of the goats presented an unbalanced udder as well as unbalanced morphology (21% to 30%) and functional milk flow (around 10% to 20% more) which could induce overmilking. In dairy sheep, selection for higher milk production increases teat angle insertion. Thus, to increase machine milk fraction, it is recommended to use either the 'Sagi hook' as an alternative for lifting up the 'pendulous' udder during milking or to perform machine stripping. There are three cluster removal strategies for small ruminants: manual, timed and milk flow driven automatic cluster removal (ACR). Automatic cluster removal reduces overmilking, improves teat condition, enables labour saving and provides a consistent milking routine in small ruminants. There are three to five main milk flow profiles in ewes and goats, which result in curves with one or two peaks (or plateau) and different patterns of the milk flow decreasing phase due to the degree of mammary gland imbalance and teat characteristics. When taking into account our current knowledge, ACR recommended take-off settings for goats are: 200 g/min+10 s delay time (DT) for a long decreasing phase or two plateau curves and 500 g/min+5 s DT for a short decreasing phase and one plateau curve. The ACR take-off settings for ewes are: 150 g/min +10 s DT for long decreasing phase and 200 g /min+5 s DT for a short decreasing phase. This review is intended to be useful for scientists and producers seeking basic knowledge of milking routines and cluster detachment settings for parlour performance and milk quality.


Assuntos
Indústria de Laticínios/métodos , Cabras/fisiologia , Lactação , Leite/metabolismo , Ovinos/fisiologia , Animais , Feminino , Glândulas Mamárias Animais/fisiologia , Leite/normas , Ruminantes
9.
Animal ; 13(S1): s94-s99, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280747

RESUMO

Because of technical limitations, an impact of machine milking on the teat tissue cannot be avoided. The continuance of this impact during and after milking depends on a variety of factors related to the physiological regulation of milk ejection, as well as the different production systems and milking machine settings. Milking machine settings aim to achieve a high milking performance, that is, short machine-on time at a maximum of milk harvest. However, a high milking performance level is often related to an impact on the teat tissue caused by vacuum or liner compression that can lead to pathological dimensions of congestion of the tissue or hyperkeratosis as a long-term effect. Toward the end of milking a decrease of milk flow rate causes a raise of mouthpiece and teat end vacuum levels and hence an increase of the impact on the teat tissue and the risk of tissue damage. The mechanical stress by the milking machine activates a cascade of cellular mechanisms that lead to an excessive keratin growth and thickening of the keratin layer. Consequently, a complete closure of the teat canal is disabled and the risk of bacterial invasion and intramammary infection increases. Another consequence of high vacuum impact is fluid accumulation and congestion in the tissue of teat tip and teat basis because of an obstruction in venous return. The present review paper provides an overview of the available scientific information to describe the interaction between different levels and types of system vacuum, mouthpiece chamber vacuum, teat end (claw) vacuum, liner pressure, and the risk of short-term and long-term impacts on the teat tissue.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Leite/metabolismo , Animais , Indústria de Laticínios/instrumentação , Feminino , Fatores de Tempo , Vácuo
10.
Animal ; 13(S1): s11-s19, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280748

RESUMO

Milk production by the sow is a major factor limiting the growth and survival of her litter. Understanding the process of morphogenesis of the sow's mammary gland and the factors that regulate mammary development are important for designing successful management tools that may enhance milk production. Primordia of the mammary glands are first observable in the porcine embryo at approximately 23 days of gestation. The glands then progress through a series of morphologically distinct developmental stages such that, at birth, each mammary gland is composed of the teat, an organized fat pad and two separate lactiferous ducts each with a few ducts branching into the fat pad. The glands continue to grow slowly until about 90 days of age when the rate of growth increases significantly. The increased rate of mammary gland growth coincides with the appearance of large ovarian follicles and an increase in circulating estrogen. After puberty, the continued growth of the gland and elongation and branching of the duct system into the fat pad takes place in response to the elevated levels of estrogen occurring as part of the estrous cycles. After conception, parenchymal mass of each gland increases slowly during early pregnancy and then grows increasingly rapidly during the final trimester. This growth is in response to estrogen, progesterone, prolactin and relaxin. Lobuloalveolar development occurs primarily during late pregnancy. By parturition, the fat pad of the mammary gland has been replaced by colostrum-secreting epithelial cells that line the lumen of the alveoli, lobules and small ducts. All mammary glands develop during pregnancy, however, the extent of development is dependent on the location of the mammary gland on the sow's underline. The mammary glands undergo significant functional differentiation immediately before and after farrowing with the formation of colostrum and the transition through the stages of lactogenesis. Further growth of the glands during lactation is stimulated by milk removal. Individual glands may grow or transiently regress in response to the intensity of suckling during the initial days postpartum. Attempts to enhance milk production by manipulation of mammary development at stages before lactation generally have met with limited success. A more in depth understanding of the processes regulating porcine mammary gland morphogenesis at all stages of development is needed to make further progress.


Assuntos
Colostro/metabolismo , Hormônios Esteroides Gonadais/metabolismo , Glândulas Mamárias Animais/crescimento & desenvolvimento , Leite/metabolismo , Suínos/crescimento & desenvolvimento , Animais , Células Epiteliais/metabolismo , Estrogênios/metabolismo , Ciclo Estral , Feminino , Desenvolvimento Fetal , Lactação , Glândulas Mamárias Animais/embriologia , Glândulas Mamárias Animais/fisiologia , Parto , Gravidez , Progesterona/metabolismo , Prolactina/metabolismo , Suínos/embriologia , Suínos/fisiologia
11.
Animal ; 13(S1): s52-s64, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280749

RESUMO

The mammary tissue is characterized by its capacity to adapt in response to a wide variety of changing conditions. This adaptation capacity is referred to as the plasticity of mammary tissue. In dairy ruminants, lactation is challenged by modifications that can either be induced on purpose, such as by modifying management practices, or occur involuntarily, when adverse environmental constraints arise. These modifications can elicit both immediate changes in milk yield and composition and carryover effects that persist after the end of the challenge. This review focuses on the current knowledge concerning the cellular mechanisms underlying mammary tissue plasticity. The main mechanisms contributing to this phenomenon are changes in the activity and number of mammary epithelial cells (MECs). Changes in the number of these cells result from variations in the rates of cell proliferation and death as well as changes in the rate MEC exfoliation. The number of MECs also depends on the number of resident adult mammary stem cells and their progenitors, which can regenerate the pools of the various mammary cells. Several challenges, including changes in milking frequency, changes in level of feed supply and hormonal manipulations, have been shown to modulate milk yield together with changes in mammary cell activity, turnover and exfoliation. Epigenetic changes may be an additional mechanism of adaptation. Indeed, changes in DNA methylation and reductions in milk yield have been observed during once-daily milking and during mastitis in dairy cows and may affect cell activity persistently. In contrast to what has been assumed for a long time, no carryover effect on milk yield were observed after feed supply challenges in dairy cows and modification of milking frequency in dairy goats, even though the number of mammary cells was affected. In addition, mammary tissue plasticity has been shown to be influenced by the stage of lactation, health status and genetic factors. In conclusion, the cellular mechanisms underlying mammary tissue plasticity are diverse, and the mammary tissue either does or does not show elastic properties (with no permanent deformation), in response to environmental changes.


Assuntos
Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Leite/metabolismo , Ruminantes/fisiologia , Animais , Contagem de Células/veterinária , Proliferação de Células , Indústria de Laticínios , Células Epiteliais/fisiologia , Feminino
12.
Animal ; 13(S1): s42-s51, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280751

RESUMO

Shortening or omitting the dry period improves the energy balance and metabolic status of dairy cows in early lactation. Metabolic, behaviour and welfare effects throughout lactation, however, are unclear. The current paper reviews long-term metabolic and welfare consequences of short and no dry period, as well as feeding strategies and individual cow characteristics that could support in optimising management of cows with a short or no dry period. The paper will conclude with impacts of short and no dry periods at herd level and in practice. Energy balance after no or a short dry period is more positive during the complete subsequent lactation. After the initial improvement in early lactation, cows after no dry period tend to fatten and may have a too low lactation persistency to be continuously milked until the onset of the subsequent lactation. Reducing dietary energy level for cows with no dry period reduced fattening during the complete lactation but did not improve lactation persistency. Feeding a more lipogenic diet for cows with a short or no dry period did not affect the energy balance or lactation persistency during the complete lactation, although a lipogenic diet resulted in lower plasma insulin and IGF-1 concentration and greater plasma growth hormone concentration, compared with a glucogenic diet. Effects of dry period length on udder health are ambiguous, whereas short and no dry periods improved fertility in most studies. Omission of the dry period changed behaviour of cows both before and after calving, with a longer lying time and greater feed intake after calving, suggesting a better adaptation to a new lactation. Individual cow characteristics like parity, genotype, prepartum body condition score, and milk yield level determined the metabolic response of cows to a short or no dry period. In conclusion, short or no dry periods increase the energy balance in the complete lactation. Feeding strategies can be used to limit fattening of cows with no or short dry period, but the studied feeding strategies did not increase lactation persistency. Improved fertility and behavioural changes around calving suggest a better adaptation to a new lactation in case of no dry period. Customised dry period lengths for individual cows could improve metabolic status of cows at risk of a severe negative energy balance while minimising milk losses.


Assuntos
Bem-Estar do Animal , Bovinos/fisiologia , Metabolismo Energético , Lactação/fisiologia , Leite/metabolismo , Animais , Dieta/veterinária , Feminino , Glucose/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Glândulas Mamárias Animais/fisiologia , Paridade , Gravidez
13.
Animal ; 13(S1): s4-s10, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31280752

RESUMO

Historically, pre-pubertal development of the bovine mammary gland (MG) has received little attention compared to later development. Recent evidence suggests not only that this period represents a very active time in the development of the MG but also that the first 90 days of life can partially dictate future productivity of the lactating cow. The MG, often considered quiescent during early life (first 3 months), is now known to increase in size by over 60-fold in the same period. The importance of sex steroids in MG development is well classified, but a complex signaling network exists among estrogen, progesterone and other growth factors and hormones. Complicating our understanding of this developmental period further is the discovery that pre-weaning nutrition of the calf not only influences the growth of the mammary parenchyma but may also alter the way in which it responds to mammogenic stimuli. Recent data suggest that feeding calves a higher plane of nutrition improves the ability of the mammary epithelium to respond to estradiol and also alters the way in which the mammary parenchyma and fat pad communicate. It is clear that early life nutrition, although able to influence the MG, is still poorly understood mechanistically. For example, additional evidence suggests that increased feeding rates in early life alter the morphology of myoepithelial cells in the mammary epithelium. Further data have also suggested a role for other cell types, such as immune cells, in the penetration of the mammary parenchyma into the fat pad during the early life development of the MG suggesting that mammary development is not only controlled by the local tissue population (parenchyma and fat pad) but perhaps systemically by other tissue types (i.e., immune system). Understanding the roles of these various stimuli and signaling pathways as they relate to the development of the MG in early life may hold the key to unlocking the potential for the optimal development of this crucial organ and, in turn, may lead to improvements in other phases of mammary development and milk yield potential.


Assuntos
Bovinos/crescimento & desenvolvimento , Hormônios Esteroides Gonadais/metabolismo , Glândulas Mamárias Animais/crescimento & desenvolvimento , Leite/metabolismo , Tecido Adiposo/metabolismo , Animais , Bovinos/fisiologia , Células Epiteliais/metabolismo , Estradiol/metabolismo , Estrogênios/metabolismo , Feminino , Lactação , Glândulas Mamárias Animais/fisiologia , Estado Nutricional , Progesterona/metabolismo , Desmame
14.
J Dairy Res ; 86(2): 196-200, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31169089

RESUMO

Automatic cluster remover (ACR) settings regulate the end of milking by detaching the clusters based on milk flow dropping below a preset level, which needs to be standardised for different breeds of dairy animals based on their production. A study was conducted to find out the best ACR setting for milking Indian crossbred cows based on milkability, milking irregularities and milk quality. Fifty six crossbred dairy cows in lactations 1 to 4 were categorised into three groups based on the level of production; low (N = 16; 18 kg/d). The ACR settings tested were 0.1, 0.2, 0.3 and 0.4 kg/min, keeping the vacuum level and pulsation settings constant. The ACR settings significantly (P < 0.01) affected the milk yield at all levels of production with a significant effect (P < 0.01) on machine-on time at 0.4 kg/min. The yield during the first 2 min of milking, average flow and peak flow rates were not affected at any level of production. The average electrical conductivity in milk was significantly (P < 0.01) lower for the low and medium yield cows without affecting the mean somatic cell count. At 0.4 kg/min, more cluster reattachments were needed because of significant amount of milk remaining in the udders post-cluster removal.


Assuntos
Bovinos/genética , Indústria de Laticínios/instrumentação , Leite/normas , Criação de Animais Domésticos , Animais , Indústria de Laticínios/métodos , Feminino , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Vácuo
15.
Life Sci ; 231: 116521, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31152814

RESUMO

INTRODUCTION: Telocytes (TCs) are recently described to integrate a variety of different cells. AIM OF THE WORK: The aim was to investigate the presence of TCs in the rat mammary gland at its different physiological stages. MATERIAL AND METHODS: Twenty four adult female albino rats were classified into 4 groups: resting, mid-pregnancy, lactating, and involution groups. Inguinal mammary glands were processed for immunohistochemical and transmission electron microscopic (TEM) examination. RESULTS: TCs were immune-positive for c-kit and CD34 and showed significant differences in the different studied groups indicating variable roles at the different stages. TEM results characterized TCs by its shape and the long slender and moniliform telopodes linking the cells into stromal networks. The extracellular exosomes, homo-cellular synapsis and hetero-cellular synapsis were observed. CONCLUSION: Our study provides evidence for the presence of TCs in all stages of the gland; not only in the resting stage as proved by other studies, but with immune-labeling differences suggesting different structural and physiological roles of TCs according to the stage requirements. These functions might via controlling the proliferation during pregnancy and lactation and the involution of the gland after weaning. Thus, more future functional studies of TCs will be important to help understanding the mechanism by which TCs contribute to tissue homeostasis concerning the role of the stromal/epithelial interactions in mammary gland biology and pathology including breast cancer which would be revolutionary for future therapeutic applications.


Assuntos
Glândulas Mamárias Animais/fisiologia , Telócitos/fisiologia , Telócitos/ultraestrutura , Animais , Antígenos CD34/metabolismo , Antígenos CD34/fisiologia , Tecido Conjuntivo , Feminino , Imuno-Histoquímica , Lactação , Glândulas Mamárias Animais/citologia , Microscopia Eletrônica de Transmissão , Gravidez , Proteínas Proto-Oncogênicas c-kit/metabolismo , Proteínas Proto-Oncogênicas c-kit/fisiologia , Ratos , Ratos Wistar
16.
J Dairy Sci ; 102(8): 6701-6717, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202662

RESUMO

Bovine mammary gland involution, as a part of the reproductive cycle in dairy cows, is a very important remodeling transformation of the mammary gland for the subsequent lactation. There is considerable incentive to accelerate mammary gland involution to improve udder health, shorten the dry period, and simplify the management process by reducing dietary changes. The complex process of mammary involution is characterized by morphological changes in the epithelial cells and mammary tissue, changes in the composition of mammary secretions, and changes in the integrity of tight junctions. Involution is facilitated by elements of the immune system and several types of proteases and is coordinated by various types of hormones. This review first describes the involution process and then argues for the need to accelerate it. Last, this review focuses on various intervention methods for accelerating involution. Our aim is to provide a comprehensive overview of bovine mammary gland involution as well as potential techniques and new opinions for dry cow management.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Animais , Contagem de Células/veterinária , Células Epiteliais/citologia , Células Epiteliais/fisiologia , Feminino , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/imunologia , Leite
17.
J Genet ; 98(2)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31204715

RESUMO

Stanniocalcin-1 (STC1) is secreted by the variety of tissues having a major role in the regulation of calcium ions in the involuting mammary gland. The present work aims to sequence and structural characterization as well as expression profiling of STC1 gene in buffalo. Polymorphism identified in the 3-untranslated region (UTR) was analysed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) genotyping in riverine and swamp buffaloes. Expression profiling of STC1 was performed in different lactation stages of mammary gland and peripheral blood mononuclear cells to study the impact of 3'-UTR polymorphism on its expression. Different polymorphic sites were detected in the entire coding and noncoding regions of riverine and swamp buffaloes, including two INDELs. An identified polymorphic nucleotide locus A324G, having target sites for two miRNAs, namely bta-miR-2382 and bta-miR-1343, reported in cattle, was genotyped by PCR-RFLP to reveal variable allelic distribution among swamp and riverine buffaloes. Gene expression profiling across buffalo mammary tissues representing different lactation stages showed maximum expression of the STC1 gene in the involuting mammary gland. Ruminants' specific genetic variation has been observed in STC1 and its implication in buffalo mammary gland involution as well as coregulation of gene expression through miRNA binding in the 3'-UTR is suggested.


Assuntos
Búfalos/genética , Expressão Gênica , Glicoproteínas/genética , Lactação/genética , Glândulas Mamárias Animais/fisiologia , Polimorfismo Genético , Regiões 3' não Traduzidas , Alelos , Animais , Sequência de Bases , Bovinos , Feminino , Frequência do Gene , Estudos de Associação Genética , Genômica/métodos , Genótipo , Regiões Promotoras Genéticas , Característica Quantitativa Herdável
18.
Endocrinology ; 160(8): 1797-1810, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31087002

RESUMO

Prior studies have demonstrated that the calcium pump, plasma membrane calcium ATPase 2 (PMCA2), mediates calcium transport into milk and prevents mammary epithelial cell death during lactation. PMCA2 also regulates cell proliferation and cell death in breast cancer cells, in part by maintaining the receptor tyrosine kinase ErbB2/HER2 within specialized plasma membrane domains. Furthermore, the regulation of PMCA2 membrane localization and activity in breast cancer cells requires its interaction with the PDZ domain-containing scaffolding molecule sodium-hydrogen exchanger regulatory factor (NHERF) 1. In this study, we asked whether NHERF1 also interacts with PMCA2 in normal mammary epithelial cells during lactation. Our results demonstrate that NHERF1 expression is upregulated during lactation and that it interacts with PMCA2 at the apical membrane of secretory luminal epithelial cells. Similar to PMCA2, NHERF1 expression is rapidly reduced by milk stasis after weaning. Examining lactating NHERF1 knockout (KO) mice showed that NHERF1 contributes to the proper apical location of PMCA2, for proper apical-basal polarity in luminal epithelial cells, and that it participates in the suppression of Stat3 activation and the prevention of premature mammary gland involution. Additionally, we found that PMCA2 also interacts with the closely related scaffolding molecule, NHERF2, at the apical membrane, which likely maintains PMCA2 at the plasma membrane of mammary epithelial cells in lactating NHERF1KO mice. Based on these data, we conclude that, during lactation, NHERF1 is required for the proper expression and apical localization of PMCA2, which, in turn, contributes to preventing the premature activation of Stat3 and the lysosome-mediated cell death pathway that usually occur only early in mammary involution.


Assuntos
Glândulas Mamárias Animais/fisiologia , Fosfoproteínas/fisiologia , ATPases Transportadoras de Cálcio da Membrana Plasmática/análise , Trocadores de Sódio-Hidrogênio/fisiologia , Animais , Polaridade Celular , Feminino , Lactação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfoproteínas/análise , Trocadores de Sódio-Hidrogênio/análise
19.
J Dairy Sci ; 102(7): 6595-6602, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31103303

RESUMO

Milking cows once daily is a management tool that has been implemented to improve physical and financial results of seasonal pasture-based dairy farms. The Molly cow model integrates physiology and metabolism of dairy cattle; however, milk production during short-term changes in milking frequency (e.g., 1× milking) is not well represented. The model includes a representation of variable rates of cell quiescence and death. However, the rate constants governing cell death and the return of quiescent to active cells are not affected by milking frequency. An empirical assessment of the problem was conducted, and it was hypothesized that changing the current representation of the rate of cell death in response to short-term 1× milking would more accurately represent active and quiescent cells and improve predictions of milk production. An extra senescent cell flux was added to account for cell loss during periods of 1× milking. Additional changes included a gradual decline in the rate of 1× stimulated senescence during 1× milking, and a structural change in cell cycling between active and quiescent cells during and after short-term 1× milking. Data used for parameter estimation were obtained from 5 studies where 1× milking or different feeding strategies were tested. Parameter estimates of cell loss indicated that 1× milking would affect a small proportion of quiescent cells to cause extra cell death. This added cell senescence was influenced by the length of 1× milking such that cell senescence peaked on d 1 of 1× milking and decayed from that point. The new structure in the model includes a variable rate of cell death in response to 1× milking and a gradual rate of return of quiescent cells back to the active pool in response to switching to 2× milking after short-term 1× milking. Root mean square errors, mean bias, and slope bias declined by at least 50% for predictions of energy-corrected milk yield and fat percent. The model showed quantitative agreement with production data from short-term 1× milking. The accuracy of predictions was improved and the error was reduced by implementing modifications in the model in response to changes in milking frequency.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios , Glândulas Mamárias Animais/fisiologia , Leite , Modelos Biológicos , Animais , Indústria de Laticínios/métodos , Feminino , Lactação/fisiologia
20.
J Anim Sci ; 97(6): 2424-2432, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30982896

RESUMO

Increased milking frequency and incomplete milking have differential effects on milk yield and mammary gland physiology that are important for optimization of milking practices in dairy herds. The objectives of this experiment were to determine the effects of increased milking frequency and incomplete milking on milk production rate (MPR) and milk composition and to determine if milking 3 times daily (3×) could rescue the negative production effects of incomplete milking. Twenty-two multiparous cows were enrolled onto this experiment beginning at 5 days in milk (DIM) and continuing through 47 DIM. A split-plot design was used to randomize the 2 treatments, which were milking frequency and incomplete milking. Eleven cows were randomly assigned to be milked 2 times (2×) daily and 11 cows were randomly assigned to be milked 3×. Within each cow, a contralateral half-udder was randomly assigned to be incompletely milked (30% milk remaining in the gland; IM), and the other half-udder was randomly assigned to be milked completely (CM). Quarter-level milk yields were recorded at each milking session. Milk samples from all quarters were collected twice weekly at the beginning of the morning milking for analysis. Cows milked 2× tended to have reduced MPR compared with 3× milked cows (1.81 ± 0.06 vs. 1.97 ± 0.06 kg milk/h; P = 0.06). Half-udders that were CM and IM produced 1.09 ± 0.03 and 0.80 ± 0.03 kg milk/h, respectively. There was an interaction between incomplete milking treatment and week of lactation (P = 0.04). No interaction was detected between milking frequency and incomplete milking for MPR or milk components. Cows milked 3× had increased milk fat percent (1.93 ± 0.09% vs. 1.65 ± 0.09%, P = 0.047), decreased milk lactose percent (4.80 ± 0.04% vs. 4.93 ± 0.04%, P = 0.04), and exhibited no differences in milk protein percent or milk somatic cell count (SCC) compared with cows milked 2×. Half-udders that were IM had increased milk fat percent (2.15 ± 0.07% vs. 1.43 ± 0.07%, P < 0.0001), decreased lactose percent (4.75 ± 0.03% vs. 4.99 ± 0.03%, P < 0.0001), increased milk log10SCC (4.22 ± 0.05 vs. 4.41 ± 0.05, P = 0.0004), and no differences in milk protein percent compared with CM half-udders. These results indicate that a 3× milking frequency in IM half-udders was not able to improve milk production compared with IM half-udders milked 2×. Our results indicate that 30% milk remaining in the gland had an irreversible impact on milk yield as increased milking frequency was not able to reverse the milk yield lost.


Assuntos
Criação de Animais Domésticos/métodos , Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação/fisiologia , Leite/química , Animais , Feminino , Glândulas Mamárias Animais/fisiologia , Proteínas do Leite/metabolismo , Distribuição Aleatória
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