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Relationships among calving season, heat load, energy balance and postpartum ovulation of dairy cows in a subtropical environment

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Jonsson, N.N., McGowan, M. R., McGuigan, K., Davison, T.M., Hussain, A.M., Kafi, M. and Matschoss, A. (1997) Relationships among calving season, heat load, energy balance and postpartum ovulation of dairy cows in a subtropical environment. Animal Reproduction Science, 47 (4). pp. 315-326. ISSN 0378-4320

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Article Link: https://doi.org/10.1016/S0378-4320(97)00014-6

Abstract

The study was designed to examine the relationships among calving season, energy balance, temperature humidity index (THI), and postpartum ovulation in high producing cows in a subtropical environment. Holstein cows calving in a feedlot dairy in southeast Queensland during winter (n = 23) and summer (n = 21) were monitored during the first 9 weeks of lactation. Cows were weighed and blood samples collected twice weekly; plasma progesterone, plasma metabolites related to energy and mineral balance, and haematological measurements were performed. Milk production was measured, body condition score was estimated, and trans-rectal ultrasound examinations of the ovaries were each undertaken once a week. The interval between calving and first ovulation was significantly longer in cows calving in summer (22.8 vs. 17.6 days, P < 0.05). Interval from calving to the first postpartum ovulation (FOVL) was inversely related to the mean plasma glucose concentration for the first 9 weeks after calving (GLU): FOVL = 80.0 − 17.9GLU, (R2 = 0.25, P < 0.001). Plasma progesterone concentration during the life of the second corpus luteum after calving was negatively correlated with THI during the first 2 weeks after calving (r = 0.55, P < 0.001). Plasma glucose concentration (GLU) was negatively correlated with milk yield (MYD) and rectal temperature (RT), and positively correlated with plasma calcium concentraction (Ca) according to the following regression equation. GLU = 33.1 − 0.02MYD + 0.91Ca − 0.48RT, (R2 = 0.58, P = 0.0001).

Item Type:Article
Keywords:Cattle; Energy balance; Temperature humidity index; Postpartum ovulation; Seasonal dynamics
Subjects:Animal culture > Breeding and breeds
Animal culture > Cattle
Live Archive:19 Mar 2024 00:58
Last Modified:19 Mar 2024 00:58

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