الفهرس 
Transition periodOnly 14 pages are availabe for public view
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Abstract
Transition period is a very important period in dairy cattle industry and considered as the most critical period in the production cycle. It extends from 21 day before parturition to 21 day after parturition. During this period, dairy cows subjected to severe metabolic modification and uterine affections, which effect on general health of cows and predispose them to metabolic diseases and reproductive disturbances that will consequently affect negatively on future fertility of dairy cows.
The present study was conducted on a dairy farm that belongs to El-Deabat, Sohag Governorate, Egypt from November 2017 to May 2018. The herd consisted of approximately 500 lactating (Holstein Friesian dairy cow) cows with average milk yield 18 – 25 Kg. The present study was carried out on 82 pregnant dairy cows. The selected cows for this study were within the range of 2– 5 parity, 3-10 years old, The BCS was ranged 2.5 – 4 (1= emaciated and 5 = obese; Spitzer, 1986). The design of the study includes examination (rectal palpation, general health condition and gynecological examination) of selected animals (100 dairy cows) before, at day of /and after calving. Blood samples were collected twice a week at the periods from 21 days before parturition till 21 days after calving (the transition period).due to the variation between the expected and the actual date of calving, all animals were examined and sampled at average time of 20±6 days prepartum then follow up to 21days postpartum. Expected date for calving (depending on date of insemination from herd book) was assessed through rectal palpation. All data including parity, feeding, disease history and condition of previous parturition and milking of the herd were collected from the herd record data. Three blood samples (2 ml) from jugular vein / cow were taken at the same time in the morning. The first and second samples were collected either in Vacutainer tube (VACO MED) containing Ethylene Diamine Tetra-acetic acid (EDTA) as anticoagulant for measuring plasma progesterone (P4) or in Vacutainer tubes (VACO MED) containing sodium fluoride as anticoagulant for measuring serum glucose level. The third sample was collected in plain Vacutainer tubes (VACO MED) for biochemical analysis (estimation of NEFA, cholesterol, triglycerides, calcium and phosphorus). After parturition and according to health state of dairy cows combined with the information collected at calving from herd book,animals (n= 82) were classified into cows having normal pueriperium (20 cows) or abnormal pueriperium (62 cows). The cows with abnormal pueriperim (n = 62 cows) divided into two subgroups, the first subgroup (n = 34 cows) with metabolic disorders [milk fever (n = 17 cows) and ketosis (n= 17 cows)], the second subgroup was (n = 28 cows) with uterine disorders [retained fetal membranes (RFMs, n = 17 cows) and metritis (n=11 cows)].Ovarian activity was assessed by measurement of plasma progesterone level after calving and rectally till conception.
The present study revealed a significant (P < 0.05) decrease in blood glucose level in cows with abnormal puerperium than its level in normal puerperal cows. The mean levels of plasma glucose started to decrease [normal healthy cows (50.70± 1.11 mg/dl and 45.9± 1.08 mg/dl) or with metabolic disorders, milk fever (47.76±1.17 mg/dl and 43.41±1.08 mg/dl) and ketosis (44.23± 1.21 mg/dl and 41.65± 1.23 mg/dl) and uterine disorders, RFM (48.29±2.30 mg/dl and 46.23± 1.75 mg/dl) and metritis (44.45± 2.03 mg/dl and 42.45± 2.16 mg/dl)] from day -7-5 till reached the lowest levels at day of parturition [normal healthy cows (41.35± 1.01mg/dl), metabolic disorders (milk fever 32.52± 2.33 mg/dl) and ketosis (29.82± 1.99 mg/dl), uterine disorders (RFM 38.66±1.38 mg/dl and metritis 34.63± 2.25 mg/dl)].
In addition, Cows with abnormal puerperal period have a significant (P < 0.05) higher serum NEFA concentration and triglyceride than normal puerperal cows. The mean levels of serum NEFA started to increase from the last week prepartum in the four disorders under study (1.47± 0.07mmol/l, 1.84± 0.09 mmol/l, 1.67± 0.06 mmol/l and 1.20± 0.08 mmol/l, respectively), at parturition (1.40± 0.07mmol/l, 2.04± 0.09 mmol/l, 1.53± 0.08 mmol/l and 1.26± 0.09 mmol/l, respectively) and at first week postpartum (1.94± 0.06 mmol/l, 2.66± 0.12 mmol/l, 2.00± 0.07 mmol/l and 1.91± 0.08 mmol/l), till reached the highest levels at second week postpartum (2.67± 0.09 mmol/l , 2.81± 0.12 mmol/l , 2.14± 0.07 mmol/l and 1.94± 0.09 mmol/l, respectively). However, serum cholesterol and calcium concentrations were significantly (P < 0.05) lower in cows with puerperal disorders than normal puerperal cows. The mean levels of serum cholesterol started to decrease from the last week prepartum (157.94± 2.32 mg/dl, 163.00 ± 3.30 mg/dl, 160.18 ±3.33 mg/dl and 160.00 ± 1.99 mg/dl, respectively), at parturition (134.59± 1.3 mg/dl, 131.41± 1.54 mg/dl, 134.23± 1.9 mg/dl and 136.67± 1.36 mg/dl, respectively) till reached the lower levels at second week postpartum (134.29±1.5 mg/dl,124.64± 2.41 mg/dl, 131.82±3.1mg/dl and 134.09± 2.68 mg/dl, respectively). Dairy cows affected with milk fever had more significant (P<0.01) lower serum calcium (8.40± 0.11mg/dl, 7.96± 0.08 mg/dl, 6.98± 0.10 mg/dl, 6.90± 0.12 mg/dl and 7.50± 0.11mg/dl) in comparison to dairy cows with normal healthy condition or with other disorders (either metabolic or uterine). Plasma progesterone levels during -2-4 days prepartum differed significantly (P<0.05) in cows affected by metabolic disorders or uterine disorders and normal healthy cows, at day of parturition plasma p4 level was significant lower in all disorders under study (0.55± 0.01 ng/ml,0.59± 0.02 ng/ml,0.55 ± 0.02 ng/ml and 0.58± 0.02 ng/ml) than healthy cows(1.20± 0.03 ng/ml) and was also significant lower at 8-14 day postpartum in dairy cows suffered from either metabolic (0.42 ± 0.02 ng/ml and 0.49 ± 0.04 ng/ml) or uterine disorders (0.52 ± 0.04ng/ml and 0.50 ± 0.05ng/ml) than normal healthy cows at the same time (0.77 ± 0.02 ng/ml), respectively. There is highly significant (P < 0.05) difference in the number of days until first estrous cycle after calving and days open from calving to conception between cows with normal puerperal conditions and others with abnormal puerperal conditions, also number of services per conception differed significantly (P < 0.05) between the same both groups. The data showed that puerperal condition of dairy cows had determinable effect on reproductive performance. Dairy cows with abnormal pueriperim needs long times for 1stestrus and days open (81.39±1.59 and 98.65±1.99), more number of services / conception (1.70±0.08). These values were significantly (P<0.05) shorter and less number of services / conception in cows with normal puerperium (37.95± 1.16, 42.10±1.80 and 1.20±0.09), respectively.