ارزیابی ارتباط بین میزان چربی، پروتئین و نسبت چربی به پروتئین شیر و نرخ آبستنی 120 روزه در گاوهای شیری هلشتاین
محورهای موضوعی :
آسیب شناسی درمانگاهی دامپزشکی
نوید سرانجام
1
,
مهران فرهودی مقدم
2
,
قاسم اکبری
3
,
مجید محمدصادق
4
,
نیما فرزانه
5
1 - دستیار دوره تخصصی مامایی و بیماریهای تولیدمثل دام، دانشکده دامپزشکی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران.
2 - دانشیار گروه مامایی و بیماریهای تولیدمثل دام، دانشکده دامپزشکی، واحد کرج، دانشگاه آزاد اسلامی، کرج، ایران.
3 - استادیار گروه مامایی و بیماریهای تولیدمثل دام، دانشکده دامپزشکی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران.
4 - دانشیار گروه مامایی و بیماریهای تولیدمثل دام، دانشکده دامپزشکی، واحد گرمسار، دانشگاه آزاد اسلامی، گرمسار، ایران.
5 - دانشیار گروه مامایی و بیماریهای تولیدمثل دام، دانشکده دامپزشکی، دانشگاه فردوسی مشهد، مشهد، ایران.
تاریخ دریافت : 1397/09/20
تاریخ پذیرش : 1398/07/03
تاریخ انتشار : 1398/09/01
کلید واژه:
گاو‌شیری,
آبستنی,
چربی شیر,
پروتئین شیر,
چکیده مقاله :
در لیپولیز ناشی از بالانس منفی انرژی، میزان چربی شیر افزایش و میزان پروتئین آن کاهش می یابد و بدین ترتیب نسبت چربی به پروتئین افزایش پیدا می کند. هدف مطالعه حاضر، استفاده از داده های موجود در هر رکورد شیر مانند چربی، پروتئین و نسبت آن ها ، شمارش سلول های سوماتیک (somatic cell count; SCC) و نیز استفاده از سابقه گاوهای شیری، جهت پیش بینی وضعیت آبستنی ۱۲۰ روزه پس از زایش بود. بنابراین، رکورد 1279رأس گاو هلشتاین یک شکم زا و چند شکم زا در روزهای 30 و 60 شیردهی و نیز در حوالی زمان تلقیح جمع آوری شد. یافته ها نشان داد در ارزیابی آبستنی تا روز 120 پس از زایش، میزان چربی، پروتئین و نسبت آن ها (همگی برحسب درصد) در روز 30 شیردهی در گروه های غیر آبستن و آبستن به ترتیب (2/1±67/2، 04/1±62/2 و 4/0±01/1) و (16/1±87/2، 95/0±76/2 و 36/0±03/1)، در روز 60 شیردهی به ترتیب (06/1±87/2، 86/0±7/2 و 35/0±06/1) و (15/1±97/2، 9/0±73/2 و 36/0±08/1) و در حوالی تلقیح به ترتیب (2/1±62/2، 04/1±53/2 و 4/0±03/1) و (24/1±8/2، 01/1±63/2 و 5/0±06/1) بود که اختلاف آماری آن ها در دو زمان معنی دار برآورد شد (05/0>p ). تأثیر SCCدر روز 60 شیردهی بر نرخ آبستنی 120روزه معنی دار گزارش شد (023/0=p )، اما در آزمون رگرسیون لجستیک هیچ‌کدام از فاکتورهای شیر و SCC رابطه معنی داری با آبستنی 120روزه نداشتند. مدل آماری کاکس در بررسی رابطه فصول زایش (02/0=p ) ، تلقیح (00/0=p )، روزهای شیردهی (001/0=p ) و میزان تولید شیر (016/0=p ) در دوره قبل با نرخ آبستنی 120روزه نشان داد که تنها تعداد روزهای شیردهی قبلی دام (985/0=Odds ratio، 021/0=p ) و فصل تلقیح (5/7=Odds ratio، 040/0=p )در آبستنی 120روزه تأثیر دارند. نتایج این مطالعه نشان داد که فاکتورهای مربوط به شیر شامل چربی، پروتئین و نسبت آن هابر نرخ آبستنی 120روزه تأثیر نداشته و استراتژی های مدیریتی از جمله تعداد روزهای شیردهی قبلی دام و فصل تلقیح بر آن تأثیر معنی دار دارند.
چکیده انگلیسی:
Induced lipolysis by negative energy balance causes an increase in milk fat, a decrease in milk protein, and also as a consequence an increase in milk fat to protein ratio (FPR). The objective of this study was to evaluate available data in each milk record such as fat, protein and their ratio, somatic cell count (SCC) and the history of dairy cows in order to determine pregnancy risk (PR) till 120 days in milk (DIM). Therefore, the information of 1,279 primiparous and multiparous Holstein dairy cows was collected on days 30 and 60 of DIM and near the first artificial insemination (AI) postpartum. The results illustrated the amount of milk fat, protein and FPR on day 30 of DIM in non-pregnant and pregnant groups were (2.67±1.2, 2.62±1.04 and 1.01±0.4) and (2.87±1.16, 2.76±0.95 and 1.03±0.36), on day 60 of DIM were (2.87±1.06, 2.7±0.86 and 1.06±0.35) and (2.97±1.15, 2.73±0.9 and 1.08±0.36), and near the first AI were (2.62±1.2, 2.53±1.04 and 1.03±0.4) and (2.8±1.24, 2.63±1.01 and 1.06±0.5), respectively, in which their effects on PR till 120 DIM were significant at two sampling times (p < /em><0.05). The effect of SCC at day 60 of DIM on PR till 120 DIM was also significant (p < /em>=0.023); but none of the milk constituents and SCC had constant effect when analyzed by Logistic regression. Seasons of calving (p < /em>=0.02) and AI (p < /em>=0.00), previous DIM (p < /em>=0.001) and milk production (p < /em>=0.016) were analyzed by COX model and it was demonstrated that only previous DIM (p < /em>=0.021, Odds ratio=0.985) and season of AI (p < /em>=0.040, Odds ratio= 7.5) had significant effect on pregnancy till 120 DIM. The result of the present study shows that the effect of previous DIM and season of AI are significant on pregnancy till 120 DIM, but milk constituents had no effect on it.
منابع و مأخذ:
Albaaj, A., Foucras, G. and Raboisson, D. (2017). High somatic cell counts and changes in milk fat and protein contents around insemination are negatively associated with conception in dairy cows. Theriogenology, 88(15): 18-27.
Barker, A.R., Schrick, F.N., Lewis, M.J., Dowlen, H.H. and Oliver, S.P. (1998). Influence of clinical mastitis during early lactation on reproductive performance of Jersey cows. Journal of Dairy Science, 81(5): 285-1290.
Baummn D.E. and Griinari J.M. (2003). Nutritional regulation of milk fat synthesis. Annual Review of Nutrition, 23 (26): 203-227.
Berry, D.P., Buckly, F., Dillon, P., Evans, R.D., Rath, M. and Veerkamp, RF. (2003). Genetic parameters for body condition score, body weight, milk yield, and fertility estimated using random regression models. Journal of Dairy Science, 86(11): 3704-3717.
Buckley, F., O’Sullivan, K., Mee, J.F., Evans, R.D. and Dillon, P. (2003). Relationships among milk yield, body condition, cow weight, and reproduction in spring-calved Holstein-Friesians. Journal of Dairy Science, 86(7): 2308-2319.
Butler, W.R. (2003). Energy balance relationships with follicular development, ovulation and fertility in postpartum dairy cows. Live Production Science, 83(2-3): 211-218.
Butler, W.R. and Smith, R.D. (1989). Interrelationships between energy balance and postpartum reproductive function in dairy cattle. Journal of Dairy Science, 72(3): 767-783.
Cheraghi, H., Parsaeimehr, K.H., Hosseinkhani, A., Alijani, S. and Daghighkia, H. (2015). Effect of three methods of estrus synchronization: Osynch, Co-Synch and Prostaglandin on the fertility of subfertile dairy cows. Journal of Veterinary Clinical Pathology, 8(32): 631-636. [In Persian]
Coffey, M.P., Emmans, G.C. and Brotherstone, S. (2001). Genetic evaluations of dairy bulls for energy balance traits using random regression. Animal Science, 73(1): 29-40.
Cook, J.G. and Green, M.J. (2016). Use of early lactation milk recording data to predict the calving to conception interval in dairy herds. Journal of Dairy Science, 99(6):1-8.
Constable, P.D., Hinchcliff, K.W., Done, S.H. and Grunberg, W. (2017) Veterinary Medicine. 11th ed., ELSEVIER, pp: 1914-1916.
Davasaztabrizi, A. and Mehrani, K. (2017). Correlation of serum levels of T3 and T4 during the dry and postpartum
periods with ovarian rebound in primiparous and multiparous cows. Journal of Veterinary Clinical Pathology, 11(41): 63-70. [In Persian]
De Marchi, M., Toffanin, V., Cassandro, M. and Penasa, M. (2014). Invited review: Mid-infrared spectroscopy as phenotyping tool for milk traits. Journal of Dairy Science, 97(3): 1171-1186.
DePeters, E.J. and Cant, J.P. (1992). Nutritional factors influencing the nitrogen composition of bovine milk: A review. Journal of Dairy Science, 75(8): 2043-2070.
Detilleux, J.C., Grohn, Y.T., Eicker, S.W. and Quaas, R.L. (1997). Effects of left displaced abomasum on test day milk yields of Holstein cows. Journal of Dairy Science, 80(1): 121-126.
Gwazdauskas, F.C., Thatcher, W.W. and Wilcox, C.J. (1973). Physiological, environmental, and hormonal factors at insemination which may affect conception. Journal of Dairy Sciences, 56(7): 873-877.
Hamann, J. and Kromker, V. (1997). Potential of specific milk composition variables for cow health management. Livestock Production Science, 48(3): 201-208.
Heuer, C., Schukken, Y.H. and Dobbelaar, P. (1999). Postpartum body condition score and results from the first test day milk as predictors of disease, fertility, yield, and culling in commercial dairy herds. Journal of Dairy Science, 82(2): 295-304.
Hudson, C.D., Bradley, A.J., Breen, J.E. and Green, M.J. (2012). Associations between udder health and reproductive performance in United Kingdom dairy cows. Journal of Dairy Science, 95(7): 3683-3697.
Kawai, K., Hagiwara, S., Anri, A. and Nagahata, H. (1999). Lactoferrin concentration in milk of bovine clinical mastitis. Veterinary Research Communication, 23(7): 391-398.
Konigsson, K., Savoini, G., Govoni, N., Invernizzi, G., Prandi, A., Kindahl, H., et al. (2008). Energy balance, leptin, NEFA and IGF-I plasma concentrations and resumption of postpartum ovarian activity in Swedish Red and White breed cows. Acta Veterinaria Scandinavica, 50(3): 1-7.
Kristula, M.A., Reeves, M., Redlus, H. and Uhlinger, C. (1995). A preliminary investigation of the association between the first postpartum milk fat test and first insemination pregnancy rates. Preventive Veterinary Medicine, 23(1-2): 95-100.
Lavon, Y., Leitner, G., Klipper, E., Moallem, U, Meidan, R. and Wolfenson, D. (2011). Subclinical, chronic intramammary infection lowers steroid concentrations and gene expression in bovine preovulatory follicles. Domestic Animal Endocrinology, 40(2): 98-109.
Loeffler S.H., de Vries, M.J. and Schukken, Y.H. (1999). The effects of time of disease occurrence, milk yield and body condition on fertility of dairy cows. Journal of Dairy Science, 82(12): 2589-2604.
Loker, S., Bastin, C., Miglior, F., Sewalem, A., Schaeffer, L.R., Jamrozik, J., et al. (2011). Short communication: Estimates of genetic parameters of body condition score in the first 3 lactations using a random regression animal model. Journal of Dairy Science, 94(7): 3693-3699.
Lomander, H., Svensson, C., Hallén-Sandgren, C., Gustafsson, H. and Frössling, J. (2013). Associations between decreased fertility and management factors, claw health, and somatic cell count in Swedish dairy cows. Journal of Dairy Science, 96(10): 6315-6323.
Mackle, T.R., Dwyer, D.A., Ingvartsen, K.L., Chouinard, P.Y., Ross, D.A. and Bauman, D.E. (2000). Effects of insulin and postruminal supply of protein on use of amino acids by the mammary gland for milk protein synthesis. Journal of Dairy Science, 83(1): 93-105.
Madouasse, A., Huxley, J.N., Browne, W.J., Bradley, A.J., Dryden, I.L. and Green, M.J. (2010). Use of individual cow milk recording data at the start of lactation to predict the calving to conception interval. American Dairy Science Association, 93(10): 4677-4690.
Miksa, I.R., Buckley, L.C. and Poppenga, H.R. (2004). Detection of nonesterified (free) fatty acids in bovine serum: Comparative evaluation of two methods. Journal of Veterinary Diagnostic Investigation, 16(1): 139-144.
Miller, R.H., Clay, J.S. and Norman, H.D. (2001). Relationship of somatic cell score with fertility measures. Journal of Dairy Science, 84(11): 2543-2548.
Moreira, F., Orlandi, C., Risco, C.A., Mattos, R., Lopes, F. and Thatcher, W.W. (2001). Effects of presynchronization and bovine somatotropin on pregnancy rates to a timed artificial insemination protocol in lactating dairy cows. Journal of Dairy Science, 84(7): 1646-1659.
Morton, J., Auldist, M.J., Douglas, M.L. and Macmillan, K.L. (2016). Associations between milk protein concentration, milk yield, and reproductive performance in dairy cows. Journal of Dairy Science, 99(12): 10033-10043.
Morton, J., Auldist, M.J., Douglas, M.L. and Macmillan, K.L. (2017). Milk protein concentration, estimated breeding value for fertility, and reproductive performance in lactating dairy cows. Journal of Dairy Science, 100(7): 5850-5862.
Negussie, E., Strandén, I. and Mäntysaari, E.A. (2013). Genetic associations of test-day fat:protein ratio with milk yield, fertility, and udder health traits in Nordic Red cattle. American Dairy Science Association, 96(2): 1237-1250.
NRC. (2001). Nutrient Requirements of Dairy Cattle. 7th rev. ed. The National Academies Press, Washington, DC.
Patton, J., Kenny, D.A., Mc Namara, S., Mee, J.F., O’Mara, F.P., Diskin, M.J., et al. (2007). Relationships among milk production, energy balance, plasma analytes, and reproduction in Holstein-Friesian cows. Journal of Dairy Science, 90(2): 649-658.
Podpecan, O., Mrkun, J. and Petra, Z. (2010). The evaluation of FPR in milk as an indicator of calving to conception interval in dairy cows using various biostatical methods. Acta Veterinaria (Beograd), 60(5-6): 541-550.
Pryce, J.E., Coffey, M.P. and Brotherstone, S. (2000). The genetic relationship between calving interval, body condition score and linear type and management traits in registered Holsteins. Journal of Dairy Sciences, 83(11): 2664-2671.
Rezayi, A., Amouoghli Tabrizi, B. and Saber Marouf, B. (2012). Evaluation of the levels of Leptin, Beta hydroxyl butyrate, Glucose, Cholesterol and Triglyceride in serum of Holstein cows with sub clinical ketosis. Journal of Veterinary Clinical Pathology, 6(3): 1647-1656. [In Persian]
Ricardo C. and Chebel R.C. (2007). Mastitis effects on reproduction. NMC Regional Meeting Proceedings, pp: 43-55.
Souza, A.H., Ayres, H., Ferreira, R.M. and Wiltbank, M.C. (2008). A new presynchronization system (Double-Ovsynch) increases fertility at first postpartum timed AI in lactating dairy cows. Theriogenology 70(2): 208-215.
Van Straten, M., Friger, M. and Shpigel, N.Y. (2009). Events of elevated somatic cell counts in high-producing dairy cows are associated with daily body weight loss in early lactation. Journal of Dairy Science, 92(9): 4386-4394.
Waldmann, A., Kurykin, U., lle Jaakma, Kaart, T., Aidnik, M., Jalakas, M., et al. (2006). The effects of ovarian function on estrus synchronization with PGF in dairy cows. Theriogenology, 66(5): 1364-1374.
_||_
Albaaj, A., Foucras, G. and Raboisson, D. (2017). High somatic cell counts and changes in milk fat and protein contents around insemination are negatively associated with conception in dairy cows. Theriogenology, 88(15): 18-27.
Barker, A.R., Schrick, F.N., Lewis, M.J., Dowlen, H.H. and Oliver, S.P. (1998). Influence of clinical mastitis during early lactation on reproductive performance of Jersey cows. Journal of Dairy Science, 81(5): 285-1290.
Baummn D.E. and Griinari J.M. (2003). Nutritional regulation of milk fat synthesis. Annual Review of Nutrition, 23 (26): 203-227.
Berry, D.P., Buckly, F., Dillon, P., Evans, R.D., Rath, M. and Veerkamp, RF. (2003). Genetic parameters for body condition score, body weight, milk yield, and fertility estimated using random regression models. Journal of Dairy Science, 86(11): 3704-3717.
Buckley, F., O’Sullivan, K., Mee, J.F., Evans, R.D. and Dillon, P. (2003). Relationships among milk yield, body condition, cow weight, and reproduction in spring-calved Holstein-Friesians. Journal of Dairy Science, 86(7): 2308-2319.
Butler, W.R. (2003). Energy balance relationships with follicular development, ovulation and fertility in postpartum dairy cows. Live Production Science, 83(2-3): 211-218.
Butler, W.R. and Smith, R.D. (1989). Interrelationships between energy balance and postpartum reproductive function in dairy cattle. Journal of Dairy Science, 72(3): 767-783.
Cheraghi, H., Parsaeimehr, K.H., Hosseinkhani, A., Alijani, S. and Daghighkia, H. (2015). Effect of three methods of estrus synchronization: Osynch, Co-Synch and Prostaglandin on the fertility of subfertile dairy cows. Journal of Veterinary Clinical Pathology, 8(32): 631-636. [In Persian]
Coffey, M.P., Emmans, G.C. and Brotherstone, S. (2001). Genetic evaluations of dairy bulls for energy balance traits using random regression. Animal Science, 73(1): 29-40.
Cook, J.G. and Green, M.J. (2016). Use of early lactation milk recording data to predict the calving to conception interval in dairy herds. Journal of Dairy Science, 99(6):1-8.
Constable, P.D., Hinchcliff, K.W., Done, S.H. and Grunberg, W. (2017) Veterinary Medicine. 11th ed., ELSEVIER, pp: 1914-1916.
Davasaztabrizi, A. and Mehrani, K. (2017). Correlation of serum levels of T3 and T4 during the dry and postpartum
periods with ovarian rebound in primiparous and multiparous cows. Journal of Veterinary Clinical Pathology, 11(41): 63-70. [In Persian]
De Marchi, M., Toffanin, V., Cassandro, M. and Penasa, M. (2014). Invited review: Mid-infrared spectroscopy as phenotyping tool for milk traits. Journal of Dairy Science, 97(3): 1171-1186.
DePeters, E.J. and Cant, J.P. (1992). Nutritional factors influencing the nitrogen composition of bovine milk: A review. Journal of Dairy Science, 75(8): 2043-2070.
Detilleux, J.C., Grohn, Y.T., Eicker, S.W. and Quaas, R.L. (1997). Effects of left displaced abomasum on test day milk yields of Holstein cows. Journal of Dairy Science, 80(1): 121-126.
Gwazdauskas, F.C., Thatcher, W.W. and Wilcox, C.J. (1973). Physiological, environmental, and hormonal factors at insemination which may affect conception. Journal of Dairy Sciences, 56(7): 873-877.
Hamann, J. and Kromker, V. (1997). Potential of specific milk composition variables for cow health management. Livestock Production Science, 48(3): 201-208.
Heuer, C., Schukken, Y.H. and Dobbelaar, P. (1999). Postpartum body condition score and results from the first test day milk as predictors of disease, fertility, yield, and culling in commercial dairy herds. Journal of Dairy Science, 82(2): 295-304.
Hudson, C.D., Bradley, A.J., Breen, J.E. and Green, M.J. (2012). Associations between udder health and reproductive performance in United Kingdom dairy cows. Journal of Dairy Science, 95(7): 3683-3697.
Kawai, K., Hagiwara, S., Anri, A. and Nagahata, H. (1999). Lactoferrin concentration in milk of bovine clinical mastitis. Veterinary Research Communication, 23(7): 391-398.
Konigsson, K., Savoini, G., Govoni, N., Invernizzi, G., Prandi, A., Kindahl, H., et al. (2008). Energy balance, leptin, NEFA and IGF-I plasma concentrations and resumption of postpartum ovarian activity in Swedish Red and White breed cows. Acta Veterinaria Scandinavica, 50(3): 1-7.
Kristula, M.A., Reeves, M., Redlus, H. and Uhlinger, C. (1995). A preliminary investigation of the association between the first postpartum milk fat test and first insemination pregnancy rates. Preventive Veterinary Medicine, 23(1-2): 95-100.
Lavon, Y., Leitner, G., Klipper, E., Moallem, U, Meidan, R. and Wolfenson, D. (2011). Subclinical, chronic intramammary infection lowers steroid concentrations and gene expression in bovine preovulatory follicles. Domestic Animal Endocrinology, 40(2): 98-109.
Loeffler S.H., de Vries, M.J. and Schukken, Y.H. (1999). The effects of time of disease occurrence, milk yield and body condition on fertility of dairy cows. Journal of Dairy Science, 82(12): 2589-2604.
Loker, S., Bastin, C., Miglior, F., Sewalem, A., Schaeffer, L.R., Jamrozik, J., et al. (2011). Short communication: Estimates of genetic parameters of body condition score in the first 3 lactations using a random regression animal model. Journal of Dairy Science, 94(7): 3693-3699.
Lomander, H., Svensson, C., Hallén-Sandgren, C., Gustafsson, H. and Frössling, J. (2013). Associations between decreased fertility and management factors, claw health, and somatic cell count in Swedish dairy cows. Journal of Dairy Science, 96(10): 6315-6323.
Mackle, T.R., Dwyer, D.A., Ingvartsen, K.L., Chouinard, P.Y., Ross, D.A. and Bauman, D.E. (2000). Effects of insulin and postruminal supply of protein on use of amino acids by the mammary gland for milk protein synthesis. Journal of Dairy Science, 83(1): 93-105.
Madouasse, A., Huxley, J.N., Browne, W.J., Bradley, A.J., Dryden, I.L. and Green, M.J. (2010). Use of individual cow milk recording data at the start of lactation to predict the calving to conception interval. American Dairy Science Association, 93(10): 4677-4690.
Miksa, I.R., Buckley, L.C. and Poppenga, H.R. (2004). Detection of nonesterified (free) fatty acids in bovine serum: Comparative evaluation of two methods. Journal of Veterinary Diagnostic Investigation, 16(1): 139-144.
Miller, R.H., Clay, J.S. and Norman, H.D. (2001). Relationship of somatic cell score with fertility measures. Journal of Dairy Science, 84(11): 2543-2548.
Moreira, F., Orlandi, C., Risco, C.A., Mattos, R., Lopes, F. and Thatcher, W.W. (2001). Effects of presynchronization and bovine somatotropin on pregnancy rates to a timed artificial insemination protocol in lactating dairy cows. Journal of Dairy Science, 84(7): 1646-1659.
Morton, J., Auldist, M.J., Douglas, M.L. and Macmillan, K.L. (2016). Associations between milk protein concentration, milk yield, and reproductive performance in dairy cows. Journal of Dairy Science, 99(12): 10033-10043.
Morton, J., Auldist, M.J., Douglas, M.L. and Macmillan, K.L. (2017). Milk protein concentration, estimated breeding value for fertility, and reproductive performance in lactating dairy cows. Journal of Dairy Science, 100(7): 5850-5862.
Negussie, E., Strandén, I. and Mäntysaari, E.A. (2013). Genetic associations of test-day fat:protein ratio with milk yield, fertility, and udder health traits in Nordic Red cattle. American Dairy Science Association, 96(2): 1237-1250.
NRC. (2001). Nutrient Requirements of Dairy Cattle. 7th rev. ed. The National Academies Press, Washington, DC.
Patton, J., Kenny, D.A., Mc Namara, S., Mee, J.F., O’Mara, F.P., Diskin, M.J., et al. (2007). Relationships among milk production, energy balance, plasma analytes, and reproduction in Holstein-Friesian cows. Journal of Dairy Science, 90(2): 649-658.
Podpecan, O., Mrkun, J. and Petra, Z. (2010). The evaluation of FPR in milk as an indicator of calving to conception interval in dairy cows using various biostatical methods. Acta Veterinaria (Beograd), 60(5-6): 541-550.
Pryce, J.E., Coffey, M.P. and Brotherstone, S. (2000). The genetic relationship between calving interval, body condition score and linear type and management traits in registered Holsteins. Journal of Dairy Sciences, 83(11): 2664-2671.
Rezayi, A., Amouoghli Tabrizi, B. and Saber Marouf, B. (2012). Evaluation of the levels of Leptin, Beta hydroxyl butyrate, Glucose, Cholesterol and Triglyceride in serum of Holstein cows with sub clinical ketosis. Journal of Veterinary Clinical Pathology, 6(3): 1647-1656. [In Persian]
Ricardo C. and Chebel R.C. (2007). Mastitis effects on reproduction. NMC Regional Meeting Proceedings, pp: 43-55.
Souza, A.H., Ayres, H., Ferreira, R.M. and Wiltbank, M.C. (2008). A new presynchronization system (Double-Ovsynch) increases fertility at first postpartum timed AI in lactating dairy cows. Theriogenology 70(2): 208-215.
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