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‣ Chemical identity and connections of medial preoptic area neurons expressing melanin-concentrating hormone during lactation

RONDINI, Tatiane Araujo; DONATO JR., Jose; RODRIGUES, Bruno de Crudis; BITTENCOURT, Jackson Cioni; ELIAS, Carol Fuzeti
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
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36.999897%
Lactation is an energy-demanding process characterized by massive food and water consumption, cessation of the reproductive cycle and induction of maternal behavior. During lactation, melanin-concentrating hormone (MCH) mRNA and peptide expression are increased in the medial preoptic area (MPO) and in the anterior paraventricular nucleus of the hypothalamus. Here we show that MCH neurons in the MPO coexpress the GABA synthesizing enzyme GAD-67 mRNA. We also show that MCH neurons in the MPO of female rats are innervated by neuropeptides that control energy homeostasis including agouti-related protein (AgRP), alpha-melanocyte stimulating hormone (alpha MSH) and cocaine- and amphetamine-regulated transcript (CART). Most of these inputs originate from the arcuate nucleus neurons. Additionally, using injections of retrograde tracers we found that CART neurons in the ventral premammillary nucleus also innervate the MPO. We then assessed the projections of the female MPO using injections of anterograde tracers. The MPO densely innervates hypothalamic nuclei related to reproductive control including the anteroventral periventricular nucleus, the ventrolateral subdivision of the ventromedial nucleus (VMHvl) and the ventral premammillary nucleus (PMV). We found that the density of MCH-ir fibers is increased in the VMHvl and PMV during lactation. Our findings suggest that the expression of MCH in the MPO may be induced by changing levels of neuropeptides involved in metabolic control. These MCH/GABA neurons may...

‣ Avaliação das curvas de lactação de rebanhos holandeses nos estados de Minas Gerais e São Paulo; Evaluation of the lactation curves of Holstein cows from herds in Minas Gerais and São Paulo

Dias, Juliana
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/12/2011 Português
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A curva de lactação é a descrição gráfica da produção de leite em dado período de tempo, normalmente descrita por modelos matemáticos dos quais podem ser obtidos fatores multiplicativos de predição e estimativas de interesse econômico como o pico, persistência e produção acumulada aos 305 dias. Entretanto, faz-se necessário a seleção de funções de curvas para que as estimativas obtidas apresentem o menor erro de predição associado, bem como, identificar os fatores que influenciam a curva de lactação para que essas estimativas sejam desprovidas de tais fontes de variação. Desta forma, foram utilizadas cinco funções não lineares para modelar 10.679 lactações pertencentes a vacas holandesas, de grupo genético PCOD (puro por cruza de origem desconhecida), PCOC (puro por cruza de origem conhecida) e PO (puro de origem), pertencentes a 38 rebanhos agrupados em três níveis de produção, situados nos estados de São Paulo e Minas Gerais no período de 1997 a 2009. A seleção da função baseou-se simultaneamente no maior valor do coeficiente de determinação e nos menores valores do quadrado médio do erro de predição, raiz quadrada do quadrado médio do erro de predição, critério bayesiano de informação e percentual de curvas atípicas. Independente do nível de produção e ordem de lactação...

‣ Avaliação de búfalas da raça Mediterrâneo durante o período de transição e início de lactação e de bezerros lactantes até o desmame; Evaluation of Mediterranean buffalo cows during the transition period and early lactation and young calves until weaning

Verdurico, Lenita Camargo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/12/2010 Português
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Objetivou-se neste estudo avaliar búfalas da raça Mediterrâneo durante o período de transição e início de lactação e bezerros lactantes até o desmame. O experimento foi conduzido na área de produção de bubalinos junto com o Departamento de Nutrição e Produção Veterinária, pertencente à Faculdade de Medicina Veterinária e Zootecnia (FMVZ), da Universidade de São Paulo (USP), localizada no município de Pirassununga/SP. Foram utilizadas 17 matrizes mestiças da raça Mediterrânea. A produção de leite foi registrada diariamente durante todo o periodo expeirmental. As amostras utilizadas para análise da composição fisico quimica e perfil de ácidos graxos do leite foram coletadas semanalmente, sendo provenientes da única ordenha diária. Para avaliação do suplemento vitamínico foram utilizados 17 bezerros búfalos divididos em dois grupos, o primeiro o grupo controle (aleitemanto artificial) e outro grupo foi administrado aditivo vitamínico-mineral (Metacell). Para avaliação do desenvolvimento ponderal os bezerros foram pesados semanalmente e foram mensurados o perímetro torácico (PT), a altura (ALT) e o comprimento corporal (COPM). Os bezerros foram avaliados até completarem 120 dias e alojados em piquete com silagem de milho e concentrado ad libitum. Houve efeito das semanas no período de transição e início de lactação para a produção de gordura e para o peso vivo das búfalas em lactação. Entretanto não houve efeito das semanas em lactação para os valores de PL...

‣ Efeito da redução de carboidratos não fibrosos (CNF) na dieta pré e pós-parto de fêmeas ovinas sobre a lactação e o desempenho das crias; Effect of decreasing non-fiber carbohydrates (NFC) in the pre and postpartum diets on lactation performance of ewes and offspring growth

Silva, Fernanda Lavínia Moura
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/06/2014 Português
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Cento e sessenta ovelhas, no terço final da gestação, foram distribuídas em delineamento de blocos completos casualizados, para avaliar os efeitos da diminuição da concentração de CNF na dieta pré e pós-parto, sobre a lactação e o desempenho das crias após o nascimento. As dietas experimentais foram compostas por 50% de volumoso (feno de "coastcross") e 50% de concentrado, sendo o milho o principal ingrediente utilizado na dieta com mais CNF e a casca de soja o principal ingrediente da dieta com reduzido CNF, correspondendo aos tratamentos M e CS, respectivamente. Foram avaliados o CMS e as concentrações de glicose, insulina e ácidos graxos não esterificados (AGNE), 3h após a oferta de alimento nos dias 21 e 7 antes do parto e imediatamente após a parição. No dia do parto foi avaliado o peso e o escore da condição corporal (ECC) das ovelhas. Da segunda à 12ª semana de lactação, 38 ovelhas e suas respectivas crias foram utilizadas para avaliar a lactação. Após a parição as ovelhas permaneceram nos tratamentos experimentais (M e CS) pré-parto e foram blocadas de acordo com a data do parto, o sexo e o número de crias. Uma vez por semana as ovelhas foram separadas de suas crias e ordenhadas mecanicamente. Três horas após a 1° ordenha...

‣ Genetic avaluacion for persistency of lactation in Holstein cows using a random regression model

Cobuci, Jaime Araújo; Euclydes, Ricardo Frederico; Costa, Claudio Napolis; Torres, Robledo de Almeida; Lopes, Paulo Sávio; Pereira, Carmen Silva
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
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A model for analyzing test day records including both fixed and random coefficients was applied to the genetic evaluation of first lactation data for Holstein cows. Data comprising 87045 test-day milk yield records from calving between 1997 and 2001 from Holstein herds in 10 regions of the Brazilian state of Minas Gerais. Six persistency of lactation measures were evaluated using breeding values obtained by random regression analyses. The Wilmink function was used to model the additive genetic and permanent environmental effects. Residual variance was constant throughout lactation. Ranking for animals did not change among criteria for persistency measurements, but ranking changes were observed when the estimated breeding value (EBV) for persistency of lactation was contrasted with those estimated for 305-day milk yield (305MY). The rank correlation estimates for persistency of lactation and 305MY were practically the same for sire and cows, and ranged from -0.45 to 0.69. The EBVs for milk yield during lactation for sires producing daughters with superior 305MY indicate genetic differences between sires regarding their ability to transmit desirable persistency of lactation traits. This suggests that selection for total lactation milk yield does not identify sires or cows that are genetically superior in regard to persistency of lactation. Genetic evaluation for persistency of lactation is important for improving the efficiency of the milk production capacity of Holstein cows.

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

Furlanetti, Andréa Maria; Prata, Luiz Francisco
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: 121-125
Português
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Amostras quinzenais, desde o parto até o final do período de lactação, obtidas de 34 vacas de três diferentes raças e propriedades, foram analisadas quanto à presença de GMP livre. Um pool das amostras quinzenais de cada rebanho foi analisada tanto para o conteúdo de GMP livre quanto para o GMP total (liberado da k-caseína pela ação da renina), correlacionando-os com as condições sanitárias do animal e do úbere, à fase da lactação e à produção de leite. A maioria dos problemas sanitários concentrou-se próximo ao parto, com poucas e espaçadas ocorrências de mastites clínicas. Os resultados do teste de CMT mostraram reações compatíveis às fases da lactação. Para o GMP livre as maiores variações ocorreram em função do período de lactação e em conseqüência de mastites clínicas e subclínicas. Valores elevados foram observados no início da lactação (5,87mg de ácido siálico/L de leite), normalizando para valores próximos de 3,30mg/L já ao final do segundo mês e voltando a elevar-se no terço final da lactação. em média, as mesmas tendências foram observadas para o teor de GMP total liberado pela ação de coalho comercial, iniciando com valores ligeiramente elevados (35,59mg/L), tornando-se normal e assim se mantendo até o sexto mês com valores próximos a 27...

‣ Estimates of correction factors for lactation length and genetic parameters for milk yield in buffaloes

Tonhati, Humberto; Muñoz, M.F.C.; Duarte, J.M.C.; Reichert, R.H.; Oliveira, J.A.; Lima, A.L.F.
Fonte: Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária Publicador: Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: 251-257
Português
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Estimaram-se fatores de correção para produção de leite aos 90, 240, 270 e 305 dias de lactação e parâmetros genéticos e de ambiente da produção de leite ajustada para esses períodos de lactação, utilizando-se 3888 lactações de 1630 búfalas, controladas entre 1987 e 2001, em 10 rebanhos do Estado de São Paulo. Os parâmetros genéticos foram estimados por meio do método da máxima verossimilhança restrita, livre de derivadas, aplicado a um modelo animal com medidas repetidas. As estimativas de herdabilidade para produção de leite corrigida para 90, 240, 270 e 305 dias de lactação foram 0,17; 0,15; 0,14 e 0,14, respectivamente. Nessa mesma ordem de apresentação, as estimativas de repetibilidade foram 0,40; 0,44; 0,41 e 0,41. As estimativas de correlação genética entre essas produções de leite corrigidas variaram de 0,96 a 1,00. Os fatores de correção multiplicativos para as diferentes classes de duração da lactação foram eficientes para ajustar a produção de leite aos 90, 240, 270 e 305 dias de lactação.; Correction factors for milk yield at 90, 240, 270 and 305 days of lactation of buffaloes and genetic and environmental parameters for milk yield of these lactation periods were estimated. The data used consisted of 3888 lactation records of 1630 buffaloes from 10 herds reared in the State of São Paulo. Genetic parameters were estimated by the derivative free restricted maximum likelihood method...

‣ Effects of intrauterine malnutrition on brain free amino acids of young rats, after nutritional recovery during lactation period

Trindade, C. E P; De Nobrega, F. J.; Tonete, S. S Q
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 795-800
Português
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The effect of protein-calorie malnutrition during gestation on the brain amino acids of rat pups was studied following nutritional recovery during lactation. The brain amino acids of rat pups born to dam rats malnourished during gestation were studied after these rat pups received proper nutrition during lactation. Pregnant rats were fed a 1% protein diet with total caloric intake restricted to half that of controls. After birth, the offspring of rats fed on deficient diets were nurtured up to the 28th day postpartum by foster mothers receiving adequate diets. At this time, the offspring were killed. The control group consisted of offspring from pregnant rats fed a diet with adequate protein (21%) and calories during the entire gestation and lactation period. Quantitation of brain amino acids in the pups at 28 days postpartum showed lower concentrations of essential and nonessential amino acids in the rats malnourished during gestation. Concentrations of histidine, glycine, and α-aminobutyric acids were all reduced. These findings demonstrate that the brains of rat pups malnourished during gestation show persistent decreases in specific brain amino acids after adequate postpartum nutrition.

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

Furlanetti,Andréa Maria; Prata,Luiz Francisco
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2003 Português
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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...

‣ Estimates of correction factors for lactation length and genetic parameters for milk yield in buffaloes

Tonhati,H.; Muñoz,M.F.C.; Duarte,J.M.C.; Reichert,R.H.; Oliveira,J.A.; Lima,A.L.F.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2004 Português
Relevância na Pesquisa
37.08685%
Correction factors for milk yield at 90, 240, 270 and 305 days of lactation of buffaloes and genetic and environmental parameters for milk yield of these lactation periods were estimated. The data used consisted of 3888 lactation records of 1630 buffaloes from 10 herds reared in the State of São Paulo. Genetic parameters were estimated by the derivative free restricted maximum likelihood method, fitting an animal repeatability model. Heritability estimates for milk yield corrected for 90, 240, 270 and 305 days of lactation were 0.17, 0.15, 0.14 and 0.14, respectively. In this same order, repeatability estimates were 0.40, 0.44, 0.41 and 0.41. The genetic correlation estimates between these corrected milk yields ranged from 0.96 to 1.00. The multiplicative correction factors for the different classes of lactation lengths were efficient for adjustment of milk yield at 90, 240, 270 and 305 days of lactation.

‣ Genetic evaluation for persistency of lactation in Holstein cows using a random regression model

Cobuci,Jaime Araujo; Euclydes,Ricardo Frederico; Costa,Claudio Napolis; Torres,Robledo de Almeida; Lopes,Paulo Sávio; Pereira,Carmen Silva
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 Português
Relevância na Pesquisa
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A model for analyzing test day records including both fixed and random coefficients was applied to the genetic evaluation of first lactation data for Holstein cows. Data comprising 87045 test-day milk yield records from calving between 1997 and 2001 from Holstein herds in 10 regions of the Brazilian state of Minas Gerais. Six persistency of lactation measures were evaluated using breeding values obtained by random regression analyses. The Wilmink function was used to model the additive genetic and permanent environmental effects. Residual variance was constant throughout lactation. Ranking for animals did not change among criteria for persistency measurements, but ranking changes were observed when the estimated breeding value (EBV) for persistency of lactation was contrasted with those estimated for 305-day milk yield (305MY). The rank correlation estimates for persistency of lactation and 305MY were practically the same for sire and cows, and ranged from -0.45 to 0.69. The EBVs for milk yield during lactation for sires producing daughters with superior 305MY indicate genetic differences between sires regarding their ability to transmit desirable persistency of lactation traits. This suggests that selection for total lactation milk yield does not identify sires or cows that are genetically superior in regard to persistency of lactation. Genetic evaluation for persistency of lactation is important for improving the efficiency of the milk production capacity of Holstein cows.

‣ Nutritional aspects of human lactation*

Thomson, A. M.; Black, A. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1975 Português
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This paper reviews the literature on the incidence and duration of breast-feeding in various countries, the volume and composition of breast milk, the health and nutrition of breast-fed babies as judged by growth and morbidity, maternal nutritional requirements during lactation, and the effect of prolonged lactation on maternal health. It appears that lactation can be as well sustained by impoverished as by affluent mothers, and that even in communities where malnutrition is common the average growth of infants is satisfactory up to the age of about 3 months on a diet of breast milk alone. Breast milk appears to have specific anti-infective properties, but prolonged breast-feeding will not prevent infections among older infants reared in a poor environment. The authors believe that breast-feeding is the best form of nutrition for the young infant and deplore its decline in modern industrial societies. The recommendations of various FAO/WHO Expert Groups on nutritional intakes during lactation are summarized. The need for an increased daily energy intake of 4.2 MJ (1 000 kcal) is questioned, and an increase of 2.5 MJ (600 kcal) is suggested. Data on the effect of prolonged lactation on the health of the mother are scanty; body weight appears to be maintained even among poorly nourished mothers. The authors stress the need for well-planned and technically adequate studies of the material and psychological factors involved in breast feeding.

‣ Lactation and reproduction*

Thomson, A. M.; Hytten, F. E.; Black, A. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1975 Português
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The authors review the literature on the effect of lactation on fertility in the absence of contraception and on the effects of contraceptive measures on lactation. They examine data from several countries on the intervals between births and on the return of menstruation and ovulation after childbirth, comparing lactating with nonlactating women. They conclude that lactation is an inefficient contraceptive for the individual, but that in populations sustained lactation is associated with reduced fertility. Possible physiological mechanisms causing lactation amenorrhoea are discussed. Though much of the literature on the effect of contraceptives on lactation is inadequate, there is general agreement that the estrogen component of hormonal preparations has an adverse effect on lactation, but that progestins alone do not. Many questions remain. Is this effect seen in established lactation, or only in the puerperal period? Is it a direct pharmacological effect, or are pill-users the mothers least motivated to maintain breast-feeding? Does a close relationship exist between hormones given and lactation performance? The authors comment on some of the technical deficiencies of previous studies in this field and discuss practical possibilities of...

‣ Split weaning increases the incidence of lactation oestrus in boar-exposed sows

Terry, R.; Kind, K.; Hughes, P.; Kennaway, D.; Herde, P.; Van Wettere, W.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
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This study evaluated the effect of split weaning and fence-line boar exposure during lactation on the incidence of lactation oestrus. Large White and Large White × Landrace sows (parity 2.9 ± 0.17; mean ± SEM) were housed in conventional farrowing crates from day -4 to 30 post-parturition. Four treatments (n = 18) were used: control (SPW0): continuous lactation of 10 piglets with all piglets weaned on day 30 of lactation; and three split wean (SPW) treatments with 3 (SPW3), 5 (SPW5) or 7 (SPW7) of the heaviest piglets removed from the sow on day 18 lactation. From day 18 lactation all sows received 15 min daily, fence-line boar exposure in a detection mating area. Fewer sows in the SPW0 treatment (56% (10/18)) expressed a lactation oestrus compared to the SPW3, SPW5, and SPW7 treatments (83%; 89%; 94%, respectively). SPW0 sows had a lower subsequent total born compared to SPW5 or SPW7 sows (8.9 ± 1.1 vs. 12.5 ± 1.0 and 13.1 ± 1.1, respectively). Between day 18 and 30 of lactation, sows in SPW5 and SPW7 gained weight (4.5 ± 1.4 and 1.9 ± 1.4 kg, respectively) whereas SPW0 and SPW3 sows lost weight (4.9 ± 1.4 and 2.9 ± 1.4 kg, respectively) (P<0.05). Split weaned piglets were heavier at day 17 of age by 1.0 kg however by day 40 of age no weight differences were observed between piglets weaned on day 18 compared to day 30 (P<0.05). In conclusion...

‣ Perfil biopsicosocial de la madre y su relación con el abandono de lactancia materna exclusiva.; Bio-psychosocial profile of the mother and her realtion with the abandonment of exclusive maternal lactation

Cárdenas, MH.; Montes, E.; Varon, M.; Reina, R.
Fonte: Murcia : Servicio de Publicaciones de la Universidad de Murcia Publicador: Murcia : Servicio de Publicaciones de la Universidad de Murcia
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
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La lactancia materna exclusiva es una forma inigualable de nutrición infantil. Sin embargo, a pesar de la importancia que tiene la lactancia materna exclusiva, en la actualidad existe un problema de abandono precoz de la misma debido a la falta de políticas efectivas en pro de su promoción. El objetivo de esta investigación fue establecer si existe relación entre el perfil biopsicosocial de la made y el abandono de la lactancia materna exclusiva. La metodología fue enmarcada dentro del diseño cuantitativo, de tipo correlacional de corte transversal. La población fue de 106 madres de niños menores de seis meses que asistían a las consultas de niños sanos de la unidad sanitaria Dr. Cándido Díaz Carballo y el Grupo Médico Miranda, la muestra fue representativa del Universo conformada por 60 madres, distribuida en dos grupos: 30 madres que daban lactancia materna exclusiva y 30 que habían abandonado la misma. Los datos se presentan en cuadros de distribución de porcentajes utilizando el estadístico de chi cuadrado con corrección de Yates. Resultados: la edad, el aspecto psicológico, las costumbres de la madre guardan relación estadísticamente significativa con el abandono de la lactancia materna exclusiva. Se concluye que los factores biopsicosociales como son la edad...

‣ Multiple regression models for lactation curves

Pereira, Marta S. P.; Oliveira, Teresa; Mexia, João Tiago
Fonte: Universidade Aberta de Portugal Publicador: Universidade Aberta de Portugal
Tipo: Artigo de Revista Científica
Publicado em //2007 Português
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Several methods have been developed in order to study lactation curves. However, the lactation curves are often not well adjusted since several factors affect milk production. The usual model used to describe a lactation curve is Wood’s Model, which generally uses a logarithmic transformation of an incomplete gamma curve to obtain least squares estimates of three constants: a - a scaling factor associated with average daily yield; b - associated with prepeak curvature; and c associated with post-peak curvature (Wood, 1976). Some disadvantages of Wood’s model are strongly connected with the overestimation of milk production at the beginning of lactation, with underestimation of the lactation peak: the self correlated residuals and highly correlated parameter estimates (Scott et al,1996). Fleischmann’s Method is usually used to estimate total milk production. This method generally overestimates actual yields up to peak lactation as well as yield during the period following the last measurement, but underestimates yields for other periods (Norman et al, 1999). The total milk yield estimate according to this method, considers a constant daily milk production between two records and equal to the mean of these two records, which does not describe the true variation of milk secretion during lactation. The mentioned disadvantages led us to consider the milk curve concept as a graphical representation of milk production described by mathematical models. In our work we considered a new approach using polynomial regression...

‣ Lactation curves and economic results of Saanen goats fed increasing dietary energy levels obtained by the addition of calcium salts of fatty acids

Souza,Rodrigo de; Alcalde,Claudete Regina; Oliveira,Carlos Antonio Lopes de; Molina,Bruna Susan de Labio; Macedo,Francisco de Assis Fonseca de; Gomes,Ludmila Couto; Hygino,Bruna; Possamai,Ana Paula Silva
Fonte: Sociedade Brasileira de Zootecnia Publicador: Sociedade Brasileira de Zootecnia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2014 Português
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The objective of this study was to evaluate the use of calcium salts of fatty acids (CSFA) to increase the dietary energy levels for Saanen goats and their effects on the lactation curve, dry matter intake, body weight, and economic results of the goats. Twenty multiparous goats, weighing an average of 63.5±10.3 kg, were randomly assigned to one of four treatment groups, each receiving one of the following dietary energy levels: a control diet consisting of 2.6 Mcal of metabolizable energy per kg of dry matter (Mcal ME/kg DM) or a test diet supplemented with CSFA (Lactoplus®) to obtain 2.7, 2.8, or 2.9 Mcal ME/kg DM. Goats were housed in individual stalls and were fed and milked twice daily. The animals were evaluated until 180 days in milk by measuring dry matter intake and milk yield. These measurements were used to calculate feed efficiencies and the cost-benefit ratio of diet and lactation curves using Wood's nonlinear model. Increasing dietary energy levels showed no effect on body weight. Supplementation with CSFA did not limit dry matter intake; however, it changed the shape of the lactation curve by promoting a late peak lactation with a longer duration. Milk yields at 180 days in milk had a quadratic increase with a maximum energy level at 2.85 Mcal ME/kg DM. Increasing the dietary energy level for Saanen goats using CSFA changes their lactation curves...

‣ Lactation estrus induction in multi- and primiparous sows in an Australian commercial pork production system

Terry, R.; Kind, K.L.; Lines, D.S.; Kennett, T.E.; Hughes, P.E.; van Wettere, W.H.E.J.
Fonte: American Society of Animal Science Publicador: American Society of Animal Science
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
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This study evaluated the effect of full physical boar exposure and split weaning on the incidence of lactation estrus within a large commercial piggery. A total of 299 multiparous (MP; parity 2.5 ± 0.03) and 303 primiparous (PP) sows of Large White × Duroc × Landrace genetics were individually housed in conventional farrowing crates from 1 wk before expected farrowing until weaning on Day 30.7 ± 0.05 postparturition. Before shed entry, sows were allocated randomly within parity to receive either boar exposure (BE; n = 454) or no BE (No BE; n = 149). Sows assigned to receive BE were then allocated to 1 of 2 litter size treatments: litter size unchanged (BE; n = 302) or BE and the litter permanently reduced (split weaned) to 7 piglets (BESPW7; n = 152) on Day 18 of lactation. From Day 18 of lactation until weaning, sows in both BE treatments were taken daily to a detection mating area where they received 15 min of full physical BE and were artificially inseminated at the first observed estrus. Providing sows with BE increased the incidence of lactation estrus, with a further increase observed when litter size was reduced to 7 piglets (16% No BE vs. 62% BE and 75% BESPW7; P < 0.05). Multiparous sows exhibited a greater incidence of lactation estrus than PP sows irrespective of treatment (81 compared to 52%...

‣ Secretion of whey acidic protein and cystatin is down regulated at mid-lactation in the red kangaroo (Macropus rufus)

Nicholas, K R; Fisher, Juliet; Muths, Erin; Trott, Josephine; Janssens, Peter; Reich, Coralie; Shaw, Denis
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Português
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37.14275%
Milk collected from the red kangaroo (Macropus rufus) between day 100 and 260 of lactation showed major changes in milk composition at around day 200 of lactation, the time at which the pouch young begins to temporarily exit the pouch and eat herbage. The carbohydrate content of milk declined abruptly at this time and although there was only a small increase in total protein content, SDS PAGE analysis of milk revealed asynchrony in the secretory pattern of individual proteins. The levels of α-lactalbumin, β-lactoglobulin, serum albumin and transferrin remain unchanged during lactation. In contrast, the protease inhibitor cystatin, and the putative protease inhibitor whey acidic protein (WAP) first appeared in milk at elevated concentrations after approximately 150 days of lactation and then ceased to be secreted at approximately 200 days. In addition, a major whey protein, late lactation protein, was first detected in milk around the time whey acidic protein and cystatin cease to be secreted and was present at least until day 260 of lactation. The co-ordinated, but asynchronous secretion of putative protease inhibitors in milk may have several roles during lactation including tissue remodelling in the mammary gland and protecting specific proteins in milk required for physiological development of the dependent young.

‣ Estimation of sustained peak yield interval of dairy cattle lactation curves using a broken-line regression approach

Sahinler,S.
Fonte: South African Journal of Animal Science Publicador: South African Journal of Animal Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 Português
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A broken-line regression model with three straight lines and two breakpoints was used to estimate the sustained peak yield of the lactation curve. A sample of 1548 lactation records of 425 Holstein-Friesian cows was provided by the Research and Application Farm of the Agriculture Faculty of Çukurova University in Adana, Turkey. A total of 13463 test-day milk yields (kg/day), recorded once a month with electronic identification and automatic milking recording systems, between November 1994 and January 2006, were used. The data was classified as first, second, third, fourth, fifth, sixth and seventh parity, and included 4105, 3238, 2495, 1800, 1113, 641 and 71 test-day records, respectively. Times (days) at the beginning and end of sustained peak yield per parity were 73.9 - 160.2, 70.6 - 131.9, 70.8 - 130.7, 71.0 - 130.3, 71.3 - 130.4, 71.2 - 128.2 and 71.1 - 129.8, respectively. The peak yields of lactation curves were 19.1 kg/d, 21.8 kg/d, 23.8 kg/d, 24.2 kg/d, 24.2 kg/d 24.4 kg/d and 21.3 kg/d, and days in milk (DIM) at peak yields of lactation curves per parity were 126, 103, 102, 104, 106, 103 and 104, respectively. Persistency values (days) and total lactation milk yields (kg/lactation) per parity were 86.4, 61.3, 59.9, 59.3...