Heat stress has adverse effects on the reproductive performances of dairy cattle and buffaloes. The dairy sector is a more vulnerable to global warming and climate change. The temperature humidity index (THI) is the widely used index to measure the magnitude of heat stress in animals. The objective of this paper was to assess the decline in performances of reproductive traits such as service period, conception rate and pregnancy rate of dairy cattle and buffaloes with respect to increase in THI. The review stated that service period in cattle is affected by season of calving for which cows calved in summer had the longest service period. The conception rate and pregnancy rate in dairy cattle were found decreased above THI 72 while a significant decline in reproductive performances of buffaloes was observed above threshold THI 75. The non-heat stress zone (HSZ) (October to March) is favorable for optimum reproductive performance, while fertility is depressed in HSZ (April to September) and critical HSZ (CHSZ) (May and June). Heat stress in animals has been associated with reduced fertility through its deleterious impact on oocyte maturation and early embryo development. The management strategies viz., nutrition modification, environment modification and timed artificial insemination protocol are to be strictly operated to ameliorate the adverse effects of heat stress in cattle and buffaloes during CHSZ to improve their fertility. The identification of genes associated with heat tolerance, its incorporation into breeding program and the inclusion of THI covariate effects in selection index should be targeted for genetic evaluation of dairy animals in the hot climate.

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Effect of heat stress on reproductive performances of dairy cattle and buffaloes: A review.

Heat stress has adverse effects on fertility of dairy animals. Decline in fertility is linearly associated with an increase in combination of both temperature and humidity. The purpose of this study was to investigate the relationship between temperature humidity index (THI) and the pregnancy rate of Murrah buffaloes in a subtropical climate. The effects of genetic and non-genetic factors viz., sire, parity, period of calving and age group at first calving were found non-significant on pregnancy rate. The effect of THI was found significant (p<0.001) on pregnancy rate of Murrah buffaloes calved for first time and overall pregnancy rate. The threshold THI affecting the pregnancy rate was identified as THI 75. The months from October to March showed THI<75 and considered as non heat stress zone (NHSZ), while months from April to September were determined as heat stress zone (HSZ) with THI≥75. The lowest overall pregnancy rate (0.25) was obtained in July with THI 80.9, while the highest overall pregnancy rate (0.59) was found in November with THI 66.1. May and June were identified as critical heat stress zone (CHSZ) within the HSZ with maximum decline (−7%) in pregnancy rate with per unit increase in THI. The highest overall pregnancy rate was estimated as 0.45 in NHSZ with THI value 56.7 to 73.2. The pregnancy rate was found to have declined to 0.28 in HSZ with THI 73.5 to 83.7. However, the lowest pregnancy rate was estimated as 0.27 in CHSZ with THI value 80.3 to 81.6.

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Influence of Temperature and Humidity on Pregnancy Rate of Murrah Buffaloes under Subtropical Climate

Study on Managemental Practices of Buffaloes in Jaipur District of Rajasthan

Repeat breeding: Incidence, risk factors and diagnosis in buffaloes

Critical evaluation of uterine torsion in buffaloes revealed that it is the single largest cause of maternal dystocia in referral cases, its incidence ranges from 52 to 70%, and it affects buffaloes mostly towards terminal gestation. The etiology of the condition continues to be partly understood with weaker broad ligaments, smaller quantity of fetal fl uids and decrease in uterine tone and size at terminal stages of gestation coupled with inordinate fetal movements appear to be the precipitating factors. In most studies right sided uterine torsion was prevalent and postulated to be because of the presence of the rumen on the left side and absence of a muscular fold in the right broad ligament of the buffalo. During recent years it has been mentioned that due to uterine circulatory disturbances and muscle exhaustion blood parameters evaluating liver and kidney functions can be used as prognostic indicators for the future outcome of uterine torsion affected buffaloes. Diagnostic evaluation of the condition continues to be transrectal palpation of the broad ligaments which rotate along with the rotating uterus. The success of management of the condition lies in the correct and timely diagnosis and early referral to referral centers. In cases presented within 24 h of the problem, rolling is often successful in correction of the problem failing which laparohysterotomy should be performed immediately. Cervical dilation failure is observed in many buffaloes after correction of the uterine torsion and can be managed by cervical massage with sodium carboxy methyl cellulose and prostaglandin injections. Management of the general condition of the patient is of utmost signifi cance for the dam survival. It was concluded that liver and kidney function tests can prognosticate the outcome of uterine torsion and early presentation to referral centers culminate in successful management of the condition with high dam and fetal survival.

Uterine torsion in buffaloes: a critical analysis

The present study was conducted to assess the effect of climatic changes on reproductive performance of Murrah buffaloes in Punjab. Retrospective analysis of farm records of 15 years and climatic data on oestrus expression and conception interval revealed that even though buffalo calved and showed postpartum oestrus throughout the year, their seasonal pattern in postpartum oestrus incidence could be due to seasonal changes in climatic factors. Relative humidity, rainfall and vapour pressure had positive influence and air temperature and number of sunshine hours had negative influence on postpartum ovarian activity. Season of calving influenced the intervals from calving to oestrus and conception. Monsoon calving buffalo had shorter while summer and winter calving buffalo had longer intervals from calving to oestrus and conception. Parity order had negative correlations and lactation yield had positive correlations with intervals from calving to oestrus and conception. The interval from calving to oestrus was shorter than the interval from calving to conception across the season of calving, parity order and lactation yield. Therefore, it appears that climatic factors, parity order and lactation yield together with individual animal variations may have influenced the conception. However, this study suggests that further studies are required to elaborate the impact of these factors on postpartum reproductive physiology of buffalo in relation to their hormonal and metabolic environment, ovarian activity, expression of oestrus and conception during the early postpartum period.

Effect of climatic changes on reproductive performance of Murrah buffaloes in Punjab: A rertrospective analysis

The present study was undertaken to assess the activity of antioxidant enzymes, viz superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase; and extent of oxidative stress/lipid peroxidation (LPO) in the blood plasma and uterine fluid of normally calved and dystocia affected Murrah buffaloes (fetal dystocia, dystocia due to uterine torsion The results showed that both in the blood plasma and uterine fluid of dystocia affected animals (fetal dystocia and uterine torsion), malondialdehyde (MDA) production was significantly higher than in normally calved buffaloes Significant changes were observed in the enzymatic antioxidant status (GPx, GR and SOD) of normally calved buffaloes and those suffering from dystocia in the 2 types of fluid, which could be used as a marker to assess the level of oxidative stress in the latter ones during immediate calving An alternative diagnostic substrate which appeared to be effective in estimating the quantum of oxidative stress was uterine fluid In conclusion, severe damage in the cases of fetal dystocia and uterine torsion indicated progression towards deteriorative action of various reactive oxygen species and possibly severe oxidative stress which have been generated during the time of parturition

Status of oxidative stress and antioxidant enzymes in normally calved and dystocia affected buffaloes

The present study was to assess the histopathological alterations of cervix in relation to dilatation in normally calved, dystocia and uterine torsion affected PGF2α induced buffaloes. Biopsy specimens from the caudal part of the cervix were obtained from 27 pluriparous buffaloes at exactly the day of calving, immediately after calving, 24 h after calving, immediately after uterine detorsion and 24 h after uterine detorsion and medical treatment. The animals were divided into 6 groups based on the type of calving; group 1: normally calved buffaloes (n = 3); group 2: dystocia with fully dilated cervix (n = 5); group 3: dystocia but cervix failed to dilate (n = 4); group 4: torsion of uterus with fully dilated cervix (n = 5); group 5: torsion of uterus with incomplete dilatation of cervix (n = 6); and group 6: contracted cervix (n = 4). Compared to group 1, the cervical histopathology of dystocia and uterine torsion affected buffaloes revealed severe damage to epithelium with edema and hemorrhage in connective tissue. The smooth muscle cells showed coagulative necrosis, vacuolar degeneration and appeared hypertrophied. The elastic and collagen fibres were much denser. Very few polymorphonuclear cells could be traced. The inflammatory changes were chronic in groups 3, 5 and 6 leading to inability of cervix to dilate completely. Administration of PGF2α did not induce further cervical dilatation. In conclusion, severe cervical damage in the cases of dystocia and uterine torsion indicated progression towards severe inflammation and possibly failure of cervix to dilate on its own followed by per-vaginal delivery of fetus.

Histopathological observations in cervix of dystocia affected vis-à-vis normally calved buffaloes

The present study was conducted on healthy, lactating pluriparous Murrah buffaloes (n = 29), calved during December 2007 to May 2008 On the basis of season of calving the animals were divided into two group’s viz winter calving buffaloes (WCB) and summer calving buffaloes (SCB) During postpartum period, WCB had significantly (P < 005) higher blood concentration of total protein, urea nitrogen and non-esterified fatty acids whereas SCB had significantly (P < 005) higher concentration of glucose, cholesterol and creatinine Overall, fluctuations in the mean concentration of various metabolic parameters were noticed in buffaloes of both the groups

Seasonal variations in blood metabolic profiles during peri and early postpartum period in winter and summer calved buffaloes

Buffaloes (28) suffering from dystocia, presented at University Veterinary Clinics were studied postpartum for reproductive patterns, evaluation of treatment response and fertility. The animals were periodically followed up to day 42 after discharge from the hospital. All the animals had developed varying degrees of postpartum metritis. Based on the type of treatment, the buffaloes were randomly divided into group 1(8 buffaloes subjected to antibiotics alone), group 2 (12 buffaloes given both antibiotics and prostaglandin) and group 3 (8 buffaloes administered prostaglandin). The broad spectrum antibiotics were given for 5 consecutive days immediately after parturition. In group 2, prostaglandin was additionally administered (lutalyse @ 25 mg) on day 5, while in group 3, injection prostaglandins were administered on day 5 and 12 postpartum. Vaginal discharges, localization and size of uterine horns and ovarian activity were studied through per-rectal examination and later confirmed ultrasonographically. The response to double prostaglandin administration was better in respect of all the parameters for clearing of uterine tract infections. The vaginal discharge disappeared by day 14 and became odorless. The uterine involution, days to first estrus and conception and services/ conception were significantly lower in group 3. In conclusion, occurrence of uterine infections and metritis was a common finding in all handled cases of dystocia. Addition of prostaglandins in the treatment protocol proved highly beneficial to clear uterus of infections, enhance uterine involution and initiate ovarian activity in the dystocia affected buffaloes.

S Prabhakar

Papers

Effect of climatic changes on reproductive performance of Murrah buffaloes in Punjab: A rertrospective analysis

Status of oxidative stress and antioxidant enzymes in normally calved and dystocia affected buffaloes

Histopathological observations in cervix of dystocia affected vis-à-vis normally calved buffaloes

Seasonal variations in blood metabolic profiles during peri and early postpartum period in winter and summer calved buffaloes

Reproductive patterns, treatment response and fertility in dystocia affected dairy buffaloes developing postpartum metritis