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Lindkvist S, Ternman E, Ferneborg S, Bånkestad D, Lindqvist J, Ekesten B, Agenäs S. Effects of achromatic and chromatic lights on pupillary response, endocrinology, activity, and milk production in dairy cows. PLoS One 2021; 16:e0253776. [PMID: 34292974 PMCID: PMC8297800 DOI: 10.1371/journal.pone.0253776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/11/2021] [Indexed: 11/28/2022] Open
Abstract
Artificial light can be used as a management tool to increase milk yield in dairy production. However, little is known about how cows respond to the spectral composition of light. The aim of this study was to investigate how dairy cows respond to artificial achromatic and chromatic lights. A tie-stall barn equipped with light-emitting diode (LED) light fixtures was used to create the controlled experimental light environments. Two experiments were conducted, both using dairy cows of Swedish Red and light mixtures with red, blue or white light. In experiment I, the response to light of increasing intensity on pupil size was evaluated in five pregnant non-lactating cows. In experiment II 16h of achromatic and chromatic daylight in combination with dim, achromatic night light, was tested on pregnant lactating cows during five weeks to observe long term effects on milk production, activity and circadian rhythms. Particular focus was given to possible carry over effects of blue light during the day on activity at night since this has been demonstrated in humans. Increasing intensity of white and blue light affected pupil size (P<0.001), but there was no effect on pupil size with increased intensity of red light. Milk yield was maintained throughout experiment II, and plasma melatonin was higher during dim night light than in daylight for all treatments (P<0.001). In conclusion, our results show that LED fixtures emitting red light driving the ipRGCs indirectly via ML-cones, blue light stimulating both S-cones and ipRGCs directly and a mixture of wavelengths (white light) exert similar effects on milk yield and activity in tied-up dairy cows. This suggests that the spectral composition of LED lighting in a barn is secondary to duration and intensity.
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Affiliation(s)
- Sofia Lindkvist
- Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
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| | - Emma Ternman
- Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sabine Ferneborg
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Daniel Bånkestad
- Department of Horticulture and Technology, Heliospectra AB, Gothenburg, Sweden
| | - Johan Lindqvist
- Department of Horticulture and Technology, Heliospectra AB, Gothenburg, Sweden
| | - Björn Ekesten
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sigrid Agenäs
- Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Artificial long-day photoperiod in the subtropics increases body weight in goat kids born in the autumn. Small Rumin Res 2018. [DOI: 10.1016/j.smallrumres.2018.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Frieten D, Gerbert C, Koch C, Dusel G, Eder K, Hoeflich A, Mielenz B, Hammon H. Influence of ad libitum milk replacer feeding and butyrate supplementation on the systemic and hepatic insulin-like growth factor I and its binding proteins in Holstein calves. J Dairy Sci 2018; 101:1661-1672. [DOI: 10.3168/jds.2017-13603] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/28/2017] [Indexed: 01/01/2023]
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Csillik Z, Faigl V, Keresztes M, Galamb E, Hammon H, Tröscher A, Fébel H, Kulcsár M, Husvéth F, Huszenicza G, Butler W. Effect of pre- and postpartum supplementation with lipid-encapsulated conjugated linoleic acid on reproductive performance and the growth hormone–insulin-like growth factor-I axis in multiparous high-producing dairy cows. J Dairy Sci 2017; 100:5888-5898. [DOI: 10.3168/jds.2016-12124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 03/04/2017] [Indexed: 11/19/2022]
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Hernández H, Flores JA, Delgadillo JA, Fernández IG, Flores MDJ, Mejía Á, Elizundia JM, Bedos M, Ponce JL, Ramírez S. Effects of exposure to artificial long days on milk yield, maternal insulin-like growth factor 1 levels and kid growth rate in subtropical goats. Anim Sci J 2015; 87:484-91. [PMID: 26261065 DOI: 10.1111/asj.12451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/28/2015] [Accepted: 03/26/2015] [Indexed: 11/27/2022]
Abstract
This study was designed to determine whether any relationship exists between exposure to artificial long days, milk yield, maternal plasma insulin-like growth factor 1 (IGF-1) levels, and kid growth rate in goats. One group of lactating goats was maintained under naturally decreasing day length (control group; n = 19), while in another one, they were kept under artificial long days (LD group; n = 19). Milk yield was higher in goats from the LD group than that in the control group (P < 0.05). Maternal IGF-1 levels at day 57 of lactation were higher (P < 0.05) in goats from the LD group than the levels in the control group and were positively correlated with the total milk yields per goat at days 43 and 57 of lactation (r = 0.77 and r = 0.84, respectively; P < 0.01). Daily weight gain at week 4 was higher (P < 0.01) in kids from the LD group than that in kids from the control group and was correlated with total and average IGF-1 maternal levels (r = 0.60 and r = 0.60, P < 0.05). It was concluded that submitting lactating goats to artificial long days increases milk yield, plasma IGF-1 maternal levels and the growth rate of the kids.
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Affiliation(s)
- Horacio Hernández
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - José Alfredo Flores
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - José Alberto Delgadillo
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - Ilda G Fernández
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - Manuel de Jesús Flores
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - Ángel Mejía
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | | | - Marie Bedos
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - José Luis Ponce
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
| | - Sergio Ramírez
- Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
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Titto CG, Negrão JA, Titto EAL, Canaes TDS, Titto RM, Pereira AMF. Effects of an evaporative cooling system on plasma cortisol, IGF-I, and milk production in dairy cows in a tropical environment. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2013; 57:299-306. [PMID: 22580965 DOI: 10.1007/s00484-012-0554-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 04/24/2012] [Accepted: 04/26/2012] [Indexed: 05/31/2023]
Abstract
Access to an evaporative cooling system can increase production in dairy cows because of improved thermal comfort. This study aimed to evaluate the impact of ambient temperature on thermoregulation, plasma cortisol, insulin-like growth factor 1 (IGF-I), and productive status, and to determine the efficiency of an evaporative cooling system on physiological responses under different weather patterns. A total of 28 Holstein cows were divided into two groups, one with and the other without access to a cooling system with fans and mist in the free stall. The parameters were analyzed during morning (0700 hours) and afternoon milking (1430 hours) under five different weather patterns throughout the year (fall, winter, spring, dry summer, and rainy summer). Rectal temperature (RT), body surface temperature (BS), base of tail temperature (TT), and respiratory frequency (RF) were lower in the morning (P < 0.01). The cooling system did not affect RT, and both the groups had values below 38.56 over the year (P = 0.11). Cortisol and IGF-I may have been influenced by the seasons, in opposite ways. Cortisol concentrations were higher in winter (P < 0.05) and IGF-I was higher during spring-summer (P < 0.05). The air temperature and the temperature humidity index showed positive moderate correlations to RT, BS, TT, and RF (P < 0.001). The ambient temperature was found to have a positive correlation with the physiological variables, independent of the cooling system, but cooled animals exhibited higher milk production during spring and summer (P < 0.01).
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Affiliation(s)
- Cristiane Gonçalves Titto
- Laboratório de Biometeorologia e Etologia, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo/USP, Av. Duque de Caxias Norte, 225, Campus da USP, 13635-900, Pirassununga, SP, Brazil.
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Dahl GE, Tao S, Thompson IM. LACTATION BIOLOGY SYMPOSIUM: Effects of photoperiod on mammary gland development and lactation1. J Anim Sci 2012; 90:755-60. [DOI: 10.2527/jas.2011-4630] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- G. E. Dahl
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - S. Tao
- Department of Animal Sciences, University of Florida, Gainesville 32611
| | - I. M. Thompson
- Department of Animal Sciences, University of Florida, Gainesville 32611
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Collier RJ, Miller MA, McLaughlin CL, Johnson HD, Baile CA. Effects of recombinant bovine somatotropin (rbST) and season on plasma and milk insulin-like growth factors I (IGF-I) and II (IGF-II) in lactating dairy cows. Domest Anim Endocrinol 2008; 35:16-23. [PMID: 18325721 DOI: 10.1016/j.domaniend.2008.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/16/2008] [Accepted: 01/16/2008] [Indexed: 10/22/2022]
Abstract
During two studies, effects of recombinant bovine somatotropin (rbST) on plasma and milk IGF's in cows adapted to summer (S; 12 cows) or winter (W; 12 cows) conditions were evaluated. Each study consisted of on-farm periods (30 days) followed by climatology chamber periods (CC; 30 days). Cows were given daily injections of rbST, Sometribove, USAN (25mg/day; 6 cows each study) or saline (control; 6 cows each study). During on-farm periods, blood and milk (am and pm) samples were collected once weekly. During CC periods, blood samples were collected every 2 days and milk samples (am and pm) were collected daily. Plasma IGF-I and IGF-II were increased in cows treated with rbST. A pronounced seasonal pattern in basal and rbST-stimulated plasma IGF-I but not IGF-II was detected. Higher basal and rbST-stimulated plasma IGF-I concentrations in S occurred despite large decreases in feed intake and energy balance. Milk IGF-I and IGF-II was not affected by rbST treatment or season. Although milk IGF-I and IGF-II concentrations were unaffected by rbST treatment, total IGF-output increased due to increased milk yield. The observed seasonal patterns in plasma IGF-I may be indicative of seasonal differences in the coupling of the somatotropin-IGF axis. In particular, we failed to detect an uncoupling of the somatotropin-IGF-I axis in S despite an induced negative energy balance during thermal stress.
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Affiliation(s)
- Robert J Collier
- Department of Animal Science, University of Arizona, 204 Shantz Building, PO Box 210038, Tucson, AZ 85721, United States.
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Hanigan MD, Rius AG, Kolver ES, Palliser CC. A Redefinition of the Representation of Mammary Cells and Enzyme Activities in a Lactating Dairy Cow Model. J Dairy Sci 2007; 90:3816-30. [PMID: 17638992 DOI: 10.3168/jds.2007-0028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Molly model predicts various aspects of digestion and metabolism in the cow, including nutrient partitioning between milk and body stores. It has been observed previously that the model underpredicts milk component yield responses to nutrition and consequently overpredicts body energy store responses. In Molly, mammary enzyme activity is represented as an aggregate of mammary cell numbers and activity per cell with minimal endocrine regulation. Work by others suggests that mammary cells can cycle between active and quiescent states in response to various stimuli. Simple models of milk production have demonstrated the utility of this representation when using the model to simulate variable milking and nutrient restriction. It was hypothesized that replacing the current representation of mammary cells and enzyme activity in Molly with a representation of active and quiescent cells and improving the representation of endocrine control of cell activity would improve predictions of milk component yield. The static representation of cell numbers was replaced with a representation of cell growth during gestation and early lactation periods and first-order cell death. Enzyme capacity for fat and protein synthesis was assumed to be proportional to cell numbers. Enzyme capacity for lactose synthesis was represented with the same equation form as for cell numbers. Data used for parameter estimation were collected as part of an extended lactation trial. Cows with North American or New Zealand genotypes were fed 0, 3, or 6 kg of concentrate dry matter daily during a 600-d lactation. The original model had root mean square prediction errors of 17.7, 22.3, and 19.8% for lactose, protein, and fat yield, respectively, as compared with values of 8.3, 9.4, and 11.7% for the revised model, respectively. The original model predicted body weight with an error of 19.7% vs. 5.7% for the revised model. Based on these observations, it was concluded that representing mammary synthetic capacity as a function of active cell numbers and revisions to endocrine control of cell activity was meritorious.
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Affiliation(s)
- M D Hanigan
- Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
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Brandt MM, Keisler DH, Meyer DL, Schmidt TB, Berg EP. Serum hormone concentrations relative to carcass composition of a random allotment of commercial-fed beef cattle12. J Anim Sci 2007; 85:267-75. [PMID: 17179565 DOI: 10.2527/jas.2005-591] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cattle (n = 995 steers and 757 heifers) were randomly selected from a commercial abattoir (Emporia, KS) to determine the relationships between USDA quality and yield grade characteristics and serum concentrations of leptin, IGF-I, and GH. Animals were randomly selected postexsanguination on the slaughter line on 4 occasions (March, May, August, and January). Blood was collected at exsanguination and transported to the University of Missouri for analysis. Sex and hide color were recorded. Carcass data included HCW, 12th-rib fat thickness, KPH, LM area, and marbling score, which were collected from each carcass approximately 24 h postmortem. Average serum leptin concentrations were greater (P = 0.008) for heifers (11.9 ng/mL) than steers (10.9 ng/mL). Heifers had lighter carcasses (331.9 vs. 352.2 kg, P < 0.001), greater 12th-rib fat measurements (1.3 vs. 1.1 cm, P < 0.001), greater KPH (2.5 vs. 2.4%, P < 0.001), and more marbling (Small(40) vs. Small(10), P < 0.001) than steers. Positive correlations (P < 0.01) existed between leptin concentration and marbling score (r = 0.28), 12th-rib fat depth (r = 0.37), KPH (r = 0.23), and USDA yield grade (r = 0.32). Negative correlations were found between leptin and IGF-I (r = -0.11; P < 0.001) and leptin and GH (r = -0.32; P < 0.001). Negative correlations (P < 0.01) were observed for IGF-I and KPH (r = -0.23) and marbling score (r = -0.20), whereas GH was most highly negatively correlated with KPH (r = -0.23; P < 0.001). Leptin concentration accounted for variation (P < 0.001) in a model separating least squares means across USDA quality grade, separating USDA standard (8.5 ng/mL), select (10.3 ng/mL), low choice (12.2 ng/mL), and upper 2/3 choice/prime (>12.9 ng/mL) carcasses. There was no difference (P = 0.31) observed in leptin concentrations between the upper 2/3 choice and prime carcasses (12.9 and 14.2 ng/mL, respectively). Relationships within endocrine profiles and between endocrine concentrations and carcass quality characteristics may prove to be a useful tool for the prediction of beef carcass composition.
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Affiliation(s)
- M M Brandt
- Division of Animal Science, University of Missouri, Columbia 65211, USA
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Rius AG, Dahl GE. Exposure to Long-Day Photoperiod Prepubertally May Increase Milk Yield in First-Lactation Cows. J Dairy Sci 2006; 89:2080-3. [PMID: 16702273 DOI: 10.3168/jds.s0022-0302(06)72277-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exposure to a long-day photoperiod (LDPP) increases mammary and lean growth in heifers relative to a short day (SDPP). Whether these effects influence milk yield, however, is unknown. To test the hypothesis that pre-pubertal long-day exposure would increase milk production, we assigned prepubertal heifers to LDPP (16 h of light:8 h of dark; n = 16) or SDPP (8 h of light:16 h of dark; n = 16) until the onset of puberty. At puberty, heifers were commingled and housed under natural photoperiodic conditions and standard nutritional management for dairy heifers. Heifers were bred according to body weight (BW = 385 kg) and withers height (WH = 132 cm). At parturition, BW, WH, and hip height were evaluated. Analysis of Dairy Herd Improvement Association records was used to evaluate milk yield, milk components, and somatic cell scores. Relative to SDPP (n = 12), heifers on LDPP (n = 10) had greater WH (by 2.4 cm) and BW at calving (by 55 kg). Compared with heifers housed under SDPP, LDPP heifers tended to produce more milk (750 kg of 305-d projected fat-corrected milk) during the first lactation. Relative to SDPP, prepubertal heifers exposed to LDPP during the prepubertal growth phase were taller and heavier at parturition, and tended to produce more milk during their first lactation.
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Affiliation(s)
- A G Rius
- Department of Animal Sciences, University of Illinois, Urbana 61801, USA
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Rius AG, Connor EE, Capuco AV, Kendall PE, Auchtung-Montgomery TL, Dahl GE. Long-Day Photoperiod that Enhances Puberty Does Not Limit Body Growth in Holstein Heifers,. J Dairy Sci 2005; 88:4356-65. [PMID: 16291627 DOI: 10.3168/jds.s0022-0302(05)73122-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous research has demonstrated that extended photoperiod accelerates pubescence in dairy heifers thereby limiting time for mammary development, which could be detrimental to future milk yield. We hypothesized that the potential negative effects of rapid growth and puberty through long-day photoperiod (LDPP) exposure could be overcome with a greater supply of metabolizable protein in dairy heifers fed rumen-undegradable protein (RUP). In an initial slaughter study, we compared deuterium oxide (D2O) and direct chemical analysis to assess body composition at 5 and 7 mo of age in heifers (n = 20) exposed to LDPP or short-day photoperiod (SDPP). Before slaughter, D2O dilution was used to estimate body composition and results were compared with actual values determined by direct chemical analysis of body tissue. In 5-mo-old heifers, the correlations between estimates of body protein, water, and mineral contents as determined by D2O dilution and direct chemical analysis of body tissue were 0.86, 0.85, and 0.76, respectively; however, fat content values were not correlated (r = -0.068). In 7-mo-old heifers, we were unable to accurately estimate body composition using the D2O dilution method. A second study was conducted to determine if LDPP, which has previously been shown to hasten puberty, could be combined with RUP to promote lean growth without limiting body stature in prepubertal heifers. Thirty-two weaned heifers (86 +/- 2 d old; 106.2 +/- 17.3 kg of body weight) were assigned to LDPP or SDPP and RUP or control diet in a 2 x 2 factorial arrangement until the onset of puberty. Relative to SDPP, LDPP increased prolactin secretion and promoted lean growth. Exposure to LDPP also enhanced body weight, withers height, and heart girth. Furthermore, RUP supplementation increased withers height and heart girth. There was a significant interaction between LDPP and RUP for hip height. Moreover, LDPP hastened the onset of puberty. In summary, D2O was a feasible method to estimate lean composition in heifers at younger ages; however, it failed to accurately estimate body composition in heifers around puberty. Long-day photoperiod hastened puberty and accelerated lean growth without limiting skeletal growth in dairy heifers.
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Affiliation(s)
- A G Rius
- Department of Animal Sciences, University of Illinois, Urbana, 61801, USA
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Dahl GE, Petitclerc D. Management of photoperiod in the dairy herd for improved production and health. J Anim Sci 2003; 81 Suppl 3:11-7. [PMID: 15000402 DOI: 10.2527/2003.81suppl_311x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Environmental influences on lactation efficiency are frequently associated with reductions in milk output. Heat stress, for example, leads to depressed feed intake and, subsequently, losses in production. Conversely, cold stress may limit nutrients available for milk synthesis. Fortunately, one environmental factor, photoperiod, can exert a positive effect on dairy performance when managed properly. Long days have consistently been shown to improve milk yield during established lactation. In addition, photoperiod management can be used to improve heifer growth and maximize accretion of lean tissue, including mammary parenchyma. There is, however, evidence of refractoriness to long day stimulation. Recent work has focused on the dry period as a time when photoperiod manipulation can influence subsequent milk production. In contrast to lactating cows, multiparous cows benefit from exposure to short days when the dry period is followed by long days or natural photoperiod after calving. Similarly, primiparous animals also respond positively to short days late in pregnancy when subsequently exposed to long days during lactation. Furthermore, emerging evidence suggests that short days positively influence immune function in cattle. Mechanistically, it appears that prolactin has a causal relationship with the observed dairy performance effects during the dry period and on immune function, via altered sensitivity to prolactin through differential expression of prolactin receptor in multiple tissues. The objectives of this paper include a review of fundamental aspects of photoperiod physiology, integration of applied and basic research findings, and development of management recommendations for the entire life cycle of the dairy cow to optimize performance.
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Affiliation(s)
- G E Dahl
- University of Illinois, Urbana, USA.
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