Effect of Changes in Light on Hormonal Secretion and Milk Production of Dairy Cows in Early Lactation

Gustafson, Gunnela M.

doi:10.1080/09064709409410893

Cited by 7 publications

(8 citation statements)

References 39 publications

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“…A circadian rhythmicity of prolactin release was also seen with a maximum mean concentration at 04:00 h and a minimum at 14:00 h in breeding season and with a maximum value at 00:00 h and a minimum at 12:00 h in non‐breeding month. The observations on diurnal prolactin pattern in yaks seems to be in sharp contrast to those recorded in cattle and buffaloes where higher prolactin concentrations have been recorded during daytime (Singh and Madan 1993; Gustafson 1994). Diurnal rhythmicity in hormonal or biochemical constituents is influenced by many factors including metabolic rate, nutrition and environmental conditions.…”

Section: Endocrine Changes Associated With Reproductive Processes In contrasting

confidence: 74%

An Update on Reproduction in Yak and Mithun

Prakash

Sarkar

Mondal

2008

Reprod Domestic Animals

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Yak and mithun are two domesticated herbivores of high economic importance to the farming community living in highlands. Improved yak and mithun production could significantly enhance the living standards of these highlanders. Over the years, their dwindling numbers have been a cause of serious concern. In view of the lack of knowledge on the reproductive physiology of these ruminants, studies have been undertaken to investigate their reproductive endocrinology in recent years. This paper attempts to present the latest information on the endocrine changes associated with their various reproductive processes viz. growth and puberty, oestrous cyclicity and oestrous behaviour, ovulation, and, pregnancy and parturition. The paper also provides the recent developments on research done towards the enhancement of yak and mithun reproductive efficiencies through endocrine and embryo biotechniques.

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Section: Endocrine Changes Associated With Reproductive Processes In contrasting

confidence: 74%

An Update on Reproduction in Yak and Mithun

Prakash

Sarkar

Mondal

2008

Reprod Domestic Animals

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“…In cows, the concentration of plasma prolactin is lower during the dark hours than during the light hours, which indicates that a continuously increasing prolactin secretion in the last month of gestation can enhance milk production in early lactation (Gustafson, 1994). Santiago-Moreno et al (2000) demonstrated the day/night variations of prolactin secretion and the seasonal differences in the nocturnal rhythm of secretion of this hormone, in wild and domestic sheep.…”

Section: Discussionmentioning

confidence: 99%

Does melatonin treatment during lactation influence milk production in Lacaune and Assaf ewes?

Abecia

Forcada

Palacín

et al. 2005

Span. j. agric. res.

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To determine whether treatment with melatonin during lactation harms milk production, two experiments were performed. In Experiment 1, 188 Lacaune ewes, lambed between September 12 and November 1 were used, and in Experiment 2, 124 Assaf ewes that lambed between November 14 and January 11. In Experiment 1, a first milk record was obtained on February 11, which was used to divide the animals into two groups, M and C. On March 11, a subcutaneous melatonin implant was administered to M animals (n = 93), and the rest (n = 95) corresponded to the Control Group (C). In Experiment 2, the first milk record was at weaning (January 5) and, on February 15, ewes were divided into M (n = 90) and C (n = 34). From that date until dry-off, monthly milk records were obtained. In both experiments, melatonin treatment significantly increased the number of lambs produced, and no detrimental effects on milk production were detected. In conclusion, the use of melatonin to improve reproduction in dairy sheep does not interfere with milk production. Moreover, an increase in the number of lambs produced, and the greater number of ewes that can be milked in the following period because of exogenous melatonin can provide economical benefits to farms.Additional key words: dairy sheep, fecundity, fertility, reproduction.Resumen ¿Afecta el tratamiento con melatonina durante el ordeño a la producción de leche en ovejas Lacaune y Assaf?Con objeto de determinar si el tratamiento con melatonina durante el ordeño afecta negativamente a la producción lechera, se llevaron a cabo dos experimentos. En el Experimento 1 se utilizaron 188 ovejas Lacaune, paridas entre el 12 de septiembre y el 1 de noviembre, mientras que en el Experimento 2 se usaron 124 ovejas Assaf paridas entre el 14 de noviembre y el 11 de enero. En el Experimento 1 se hizo un primer control lechero el 11 de febrero, que sirvió para dividir las ovejas en dos lotes: M y C. El 11 de marzo, los animales del Grupo M (n = 93) recibieron un implante subcutáneo de melatonina. El resto (n = 95) fue considerado como lote control (Grupo C). En el Experimento 2, el primer control se realizó al destete (5 de enero) y el 15 de febrero se implantó con melatonina al Grupo M (n = 90), siendo el resto el Grupo C (n = 34). Desde ese día y hasta el secado, se tomaron controles lecheros mensuales. En ambos experimentos, el tratamiento con melatonina incrementó significativamente el número de corderos nacidos, sin un detrimento de la producción de leche. En conclusión, el uso de implantes de melatonina para incrementar los parámetros reproductivos de ovejas lecheras durante el ordeño no interfiere con la producción de leche. Es más, el incremento del número de corderos producidos y el mayor número de ovejas que entrarán en ordeño tras el siguiente parto debido al tratamiento con melatonina proporcionan un importante beneficio a las explotaciones.Palabras clave adicionales: fecundidad, fertilidad, ovino lechero, reproducción.

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“…The reports are available in cows associated with lower progesterone production due to less luteal cell populations (Wolfenson et al 1993;Younas et al 1993). This has been hypothesized that the reduction in progesterone concentration in cows reared in hot environment is due to the lower plasma cholesterol availability and the impairment of lipid metabolism that occurs under such conditions (Ronchi The concentration of plasma prolactin was lower during the dark hours than during the light hours (Gustafson 1994) in dairy cows. It may be pertinent to mention here that circadian rhythmicity in hormonal or biochemical constituents is influenced by numerous factors including metabolic rate, nutrition and environmental conditions.…”

Section: Discussionmentioning

confidence: 99%

Changes in endocrine profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers at hot summer season

Roy

Prakash

2008

Trop Anim Health Prod

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The aim of this study was to compare the changes in hormonal profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers following timed artificial insemination (TAI) at stressful summer months, through intensive endocrine analysis. The norprolac (an anti-prolactin drug) at the dose rate of 10.0 mg/animal /day effectively suppressed the level of prolactin upto 30 hours. The hormones quantified in blood plasma samples collected before, during and after ovsynch and ovsynch plus norprolac treatment were LH, prolactin, progesterone, estradiol-17beta and total estrogens. The plasma prolactin and progesterone concentrations were negatively correlated (r = - 0.24) during summer estrous cycle, which indicated prolactin-induced suppression of progesterone secretion through poor luteal development. The ovsynch treatment reduced the incidence of anestrous from 45% before treatment to only 18% after treatment. The norprolac induced prolactin suppression improved the efficiency of ovsynch treatment upto 100% cyclicity after treatment in comparison to 36% acyclicity before treatment. In both the treatments 45% and 55% of animal became pregnant after TAI, respectively. The high prolactin secretion contributed to poor fertility by lowering gonadal hormones (estradiol-17beta, total estrogens and progesterone) production in summer months. This finding of endocrine changes suggests that ovsynch protocol for estrus synchronization has potential application for improvement of fertility in repeat breeding buffaloes even during extreme summer months through suppression of prolactin secretion.

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Effect of Changes in Light on Hormonal Secretion and Milk Production of Dairy Cows in Early Lactation

Cited by 7 publications

References 39 publications

An Update on Reproduction in Yak and Mithun

An Update on Reproduction in Yak and Mithun

Does melatonin treatment during lactation influence milk production in Lacaune and Assaf ewes?

Changes in endocrine profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers at hot summer season

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