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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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Subject: Veterinary Physiology × Author: RALTE, VANLALNGILNEII × Start date: 2018 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    ULTRASONOGRAPHIC MONITORING OF OVARIAN FOLLICULAR AND LUTEAL DYNAMICS IN COW
    (College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, 2022-03) RALTE, VANLALNGILNEII; Dutta, Devojyoti
    The ovarian follicular and luteal dynamics, blood flow pattern in the corpus luteum (CL) including the pattern of follicular wave and luteal development were studied using portable ultrasound device with 5-10 MHz linear array transrectal probe in female Crossbred and Lakhimi, indigenous cattle breed of Assam. In the experiment, twelve each cyclic Crossbred (Jersey X L) and Lakhimi (L) cows were subdivided into two groups viz. Group-I/Natural or Spontaneous oestrus and Group-II/Induced or Synchronized oestrus for each breed comprising of six cows in each group. They were evaluated in the subsequent cycle of natural luteolysis (Group-I) and induced luteolysis by prostaglandin F2α (Group-II) and circulating steroids were estimated on alternate days of the cycle. From scanning the ovaries for two inter-ovulatory cycle the experimental cows exhibited two and three follicular waves per cycle. Most of the cows 30(62.50 %) exhibited 3-wave cycle and 18(37.50 %) had 2-wave cycle. The diameter of 12.4 mm and 10.5 mm were the threshold diameter for ovulation according to follicle diameter in crossbred and Lakhimi cows, respectively. The inter-ovulatory interval (IOI) was found to be significantly longer (P<0.05) in Crossbred cows experiencing 3-wave (21-22 day) than 2-wave (20-21 day) per cycle. The first wave emerged on day 0 (day of ovulation) to day 1 of cycle with mean day of 0.13 ± 0.12 to 0.83 ± 0.38 in both the breed and group. The second wave onset was significantly (P < 0.05) earlier (9.00 ± 0.19, 8.50 ± 0.22) in 3-wave cycle than the 2-wave cycle (10.50 ± 0.29, 10.67 ± 0.21) in both Crossbred and Lakhimi cows. The average number of follicles (≥ 2 mm) observed on wave onset was 10-13 in Crossbred and 9-13 in Lakhimi cows. The first wave dominant follicle (DF) became deviated in between day 3 to 4 in both the breeds, while the second wave DF deviated on day 11-12 in Crossbred and day 10-11 in Lakhimi cows exhibiting 2-wave cycle. Deviation of the third DF occurred on day 17-18 in both the breeds. Maximum mean diameter of DF in the second waves recorded as 8.74 ± 0.52 and 7.70 ± 0.27 mm in Crossbred and Lakhimi cows respectively in 3-wave cycles was significantly smaller (P < 0.05) than the second wave DF diameter (12.83 ± 0.65 and 10.53 ± 0.76 mm) in 2-wave cycles in both crossbred and Lakhimi cows. The DF maximum diameter was attained significantly (P < 0.05) earlier in 3-wave cycle in both the first and second wave than in 2-wave cycle. The average growth rate of ovulatory DF in 3-wave cycle was 1.19 and 1.37 mm/day in Group-I and II respectively in Crossbred while, 0.88 and 1.18 mm/day in Group-I and II respectively in Lakhimi. The dominant follicles of the first wave (non-ovulatory) began atresia on day 8.0 ± 0.41 at the rate of 1.36 to 1.53 mm/day in Crossbred cow and on day 7.75 ± 0.25 at the rate of 0.97 mm/day in Lakhimi cows. The developing CL was detected on day 0 to day 1 in both Crossbred and Lakhimi cows. Maximum diameter (mm) of the CL for the two and three follicular wave cycle in Lakhimi (15.29 ± 0.64 mm and 15.08 ± 0.45 mm) were significantly smaller (P <0.05) than in Crossbred cows (22.98 ± 0.87 mm and 21.94 ± 0.66 mm). Onset of luteal regression of the 2-wave cycles (day 12 to 13 ) was significantly earlier (P < 0.05) than in the 3-wave cycle (day 15 to 16 ). In early luteal phase (day 0 to 5) the Doppler signal increased to 65.73 ± 5.02 mm2 in Crossbred and 57.30 ± 9.83 mm2 in Lakhimi. During the mid-luteal phase (day 7 to 13) the area gradually increased to 119.82 ± 5.54 mm2 in Crossbred and 93.82 ± 4.12 mm2 in Lakhimi cows then rapidly declined in the late luteal phase (day 15 to 18) to 10.66 ± 2.02 mm2 in Crossbred and 11.99 ± 5.38 mm2 in Lakhimi. Similar pattern was observed in 2-wave cycle. On the day of oestrus, the mean serum Oestradiol-17β level ranged from 35.75 ± 0.64 to 51.01 ± 2.13 pg/ml in Crossbred and 32.43 ± 0.74 to 35.74 ± 0.97 pg/ml in Lakhimi while the serum progesterone level ranged from 0.58 ± 0.71 to 1.27 ± 0.33 ng/ml in crossbred and 0.43 ± 0.77 to 0.47 ± 0.76 ng/ml in Lakhimi cows. ii There was a positive correlation between LBF area and progesterone level in 2-wave crossbred (r = 0.92), 2-wave Lakhimi (r= 0.82), 3-wave crossbred (r = 0.81) and 3-wave Lakhimi (r = 0.90) during the cycle. There was positive correlation between DF size and oestradiol level in 2-wave (r = 0.40) also in 3-wave crossbred and Lakhimi cows (r = 0.41). Negative correlation was observed between DF size and progesterone level in 2-wave (r = - 0.47) and in 3-wave (r = - 0.40) in crossbred and Lakhimi cows.