Murrah Buffalo Heifers Research Articles

Growth, metabolic status and ovarian function in buffalo ( Bubalus bubalis) heifers fed a low energy or high energy diet

The aim was to establish the capacity of buffalo heifers to adapt their metabolic requirements to a low energy diet. Murrah buffalo ( Bubalus bubalis) heifers undergoing regular estrous cycles were randomly assigned by age, live weight (LW) and body condition score (BCS) to a high energy group (HE, 5.8 milk forage units (MFU)/day, n = 6) or low energy group (LE, 3.6 MFU/day, n = 6). Circulating concentrations of metabolic substrates, metabolic hormones and reproductive hormones were determined weekly for 19 weeks. Ovarian follicular characteristics and oocyte parameters were also ascertained weekly. Heifers fed the LE diet had a better dry matter conversion than heifers fed the HE diet and the calculated daily energy provision was negative for heifers fed the LE diet (−0.248 MFU) and positive for heifers fed the HE diet (5.4 MFU). Heifers fed the HE diet had an increase in 50 kg LW over the duration of the study whereas LW remained constant for heifers fed the LE diet. The BCS of heifers fed the HE diet (4.2) was greater ( P < 0.05) than the BCS for heifers fed the LE diet (3.4). Heifers fed the HE diet had greater ( P < 0.05) circulating concentrations of metabolic substrates (glucose, total cholesterol and HDL cholesterol) and metabolic hormones (insulin, glucagon, leptin and T3) compared with heifers fed the LE diet. There were no significant differences in circulating reproductive hormones between the two groups of heifers. Ovarian follicular characteristics were similar for the two groups of heifers while heifers fed the LE diet tended to have oocytes of reduced quality compared with heifers fed the HE diet. The most notable finding was that heifers fed the LE diet had a negative calculated daily energy provision but were able to maintain LW and reproductive activity. It was concluded that buffalo heifers may potentially have the capacity to undergo metabolic adjustment and reduce their energy requirements when dietary energy is limiting. This adaptive capacity would explain why buffaloes remain productive in environments that are limiting to other ruminants.

Plasma progesterone, oestradiol‐17β and total oestrogen profiles in relation to oestrous behaviour during induced ovulation in Murrah buffalo heifers

The objectives of this study were to establish the characteristics of oestrous behaviour in Ovsynch (induction of ovulation through administration of GnRH-PGF2-GnRH in a systemic manner on 0, seventh and ninth day respectively) and Ovsynch plus Norprolac (Quinagolide hydrochloride – an inhibitor of prolactin secretion) treated Murrah buffalo heifers and to determine the relationships between this behaviour and the plasma concentrations of oestradiol-17β (E2), total oestrogen, and progesterone. Oestrus was detected by visual observations of oestrus signs, per rectal examination of genitalia and bull parading thrice a day during treatment period. Among all the symptoms, it was observed that bull mounting of heifers in oestrus was highest. Examination of genital tracts per rectum revealed that the cervix was relaxed, uterus was turgid and ovaries had palpable follicle in animals with oestrus. The peak concentrations of E2 (10.81 ± 0.62 pg/ml) and total oestrogen (17.11 ± 1.21 pg/ml) occurred at 9.45 ± 0.85 and 9.64 ± 0.93 h after second GnRH administration, respectively, in Ovsynch treated animals. However, the peak levels of E2 (20.02 ± 2.87 pg/ml) and total oestrogen (32.71 ± 3.15 pg/ml) occurred at 10.18 ± 0.50 and 10.36 ± 0.75 h after second GnRH administration, respectively, in Ovsynch plus Norprolac treated animals. Plasma progesterone concentration was basal (0.20 ± 0.001 ng/ml) during the peri-oestrus period. The plasma progesterone concentration was the lowest on the day of oestrus and increased to register a peak on day 13 ± 2 of the cycle. Oestrous behaviour was positively correlated with the peak concentration of E2 (p < 0.001) and total oestrogen (p < 0.001) during the peri-oestrus period. Inhibition of prolactin by Norprolac administration significantly increased the concentration of E2 and total oestrogen during oestrus in buffaloes in comparison to those recorded in animals subjected to Ovsynch protocol alone. In conclusion, our results suggest that the peak concentrations of E2 and total oestrogen and mean level of E2 and total oestrogen during the peri-oestrus period are the important factors contributing the behavioural manifestation of oestrus in buffalo cows.

CYP19 (cytochrome P450 aromatase) gene polymorphism in murrah buffalo heifers of different fertility performance

The most common cause of infertility in buffaloes is anestrum. During late maturity the ovaries are in a state of true anestrum. One of the predominant causes of true anestrum is a low level of ovarian estrogens. The key enzyme in estrogen biosynthesis is cytochrome P450 aromatase, encoded by CYP19 gene. In the present study, CYP19 gene polymorphism was analyzed by Single Strand Conformational Polymorphism (SSCP) in buffaloes of different fertility performance. The SSCP and sequence analysis revealed 4 allelic variants in coding exons and introns which unaltered the protein sequence. However, a significant polymorphism (T/C heterozygote) was found near TATA binding protein region in regulatory part (a facet of promoter II) at position 23 of CYP19 exon 2, in all late matured and 50% of late maturing animals. Based on these observations and remarks of earlier workers, a hypothesis is proposed for the physiology of late maturity in buffaloes.

Changes in endocrine profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers at hot summer season

The aim of this study was to compare the changes in hormonal profiles during ovsynch and ovsynch plus norprolac treatment in Murrah buffalo heifers following timed artificial insemination (TAI) at stressful summer months, through intensive endocrine analysis. The norprolac (an anti-prolactin drug) at the dose rate of 10.0 mg/animal /day effectively suppressed the level of prolactin upto 30 hours. The hormones quantified in blood plasma samples collected before, during and after ovsynch and ovsynch plus norprolac treatment were LH, prolactin, progesterone, estradiol-17beta and total estrogens. The plasma prolactin and progesterone concentrations were negatively correlated (r = - 0.24) during summer estrous cycle, which indicated prolactin-induced suppression of progesterone secretion through poor luteal development. The ovsynch treatment reduced the incidence of anestrous from 45% before treatment to only 18% after treatment. The norprolac induced prolactin suppression improved the efficiency of ovsynch treatment upto 100% cyclicity after treatment in comparison to 36% acyclicity before treatment. In both the treatments 45% and 55% of animal became pregnant after TAI, respectively. The high prolactin secretion contributed to poor fertility by lowering gonadal hormones (estradiol-17beta, total estrogens and progesterone) production in summer months. This finding of endocrine changes suggests that ovsynch protocol for estrus synchronization has potential application for improvement of fertility in repeat breeding buffaloes even during extreme summer months through suppression of prolactin secretion.

Effect of including growth factors and antioxidants in maturation medium used for in vitro culture of buffalo oocytes recovered in vivo

This study examined the effect of including one of two growth factors (100 ng/ml IGF-1 or 20 ng/ml EGF) in combination with one of two antioxidants (50 μM cysteamine or 50 μM β-mercaptoethanol) in maturation, fertilization and subsequent development of buffalo oocytes. The oocytes were recovered by in vivo ovum pick-up technique from six Murrah buffalo heifers twice a week over a period of 16 weeks. Immediately after ovum pick-up oocytes recovered from six donors were allocated randomly to five different maturation treatments. The control treatment was the basic maturation medium (MM; TCM-199 supplemented with 10% FBS, 10 IU/ml LH, 0.5 μg/ml FSH, 1 μg/ml estradiol-17β and 50 μg/ml gentamicin). The other four treatments consisted of the control maturation medium (MM) plus one combination of a growth factor and an antioxidant viz. IGF-1 + cysteamine; IGF-1 + β-ME; EGF + cysteamine or EGF + β-ME. The total number of oocytes assigned to each maturation treatment ranged from 31 to 66. After maturation in different maturation medium, media used for in vitro fertilization and subsequent development of embryo was same for all groups. Data were analysed using Chi-square test. The maturation rate observed for the growth factor plus antioxidant treatments was similar to that for the control (90.4%). The highest cleavage rate recorded in the IGF-1 + cysteamine treatment (71.9%) which was significantly higher ( P < 0.05) than the IGF-1 + β-ME (45.2%) and EGF + β-ME (46.4%) treatments, but not significantly differ from the control (63.8%) and EGF + cysteamine treatment (60.7%). The proportion of cleaved oocytes those developed to blastocyst stage was significantly higher in the IGF-1 + cysteamine treatment (52.2%; P < 0.05) than in the control (23.3%), the EGF + cysteamine (13.5%) or the EGF + β-ME (7.7%) treatments, but did not differ significantly from the IGF-1 + β-ME (28.6%) treatment. Following non-surgical transfer of 15 embryos to 14 synchronized recipients, four became pregnant and only one recipient sustained the pregnancy as long as 4.5 months when spontaneous abortion occurred. It was concluded that supplementing the maturation medium with IGF-1 + cysteamine improved the production of buffalo embryos significantly in vitro culture.

Interrelationship between Heat Shock Protein 70 (HSP70) and LymphocyteProliferation in Thermal Exposed Buffalo Heifers

Effect of thermal exposure on induction of Heat Shock protein–70 (HSP70) was assessed in Murrah buffalo heifers after exposure at 450 C for 4 h in a climatic chamber. Physiological cardinal responses were measured pre-exposure, 2 h after exposure and 4 h after exposure and jugular vein blood samples were collected. Rectal temperature (RT) of buffalo heifers increased from 38.16+0.200C to 40+0.240C, pulse rate (PR) from 39+1.00 to 70+4.00 beats/min and respiratory rate (RR) from 18+1.00 to 54+2.00 breath/min after 4 h of exposure at 450C indicating that exposure was stressful. The rise in RT, PR and RR was significant at 2 h (P<0.001) and 4 h exposure (P<0.001). Heat Shock protein-70 (HSP70) and Interleukin 2 (IL–2) was assayed in the plasma of exposed heifers and lymphocyte proliferation assay was performed using whole blood method. HSP70 level in the plasma was found to be 1.42+0.10, 2.25+0.54 and 1.76+0.30 ηg/µg of protein at pre exposure, 2 h exposure and 4 h exposure, respectively. The concentrations of IL–2 and lymphocyte proliferation were highest during the pre exposure period, but HSP70 concentration was lowest prior to the exposure of heifers. No correlation was observed in between HSP70 and IL–2 and a negative correlation was observed in between HSP70 and lymphocyte proliferation. A positive correlation was observed between IL–2 and lymphocyte proliferation. The study indicated that thermal exposure of buffaloes caused induction of HSP70 and declined the immune status of buffalo heifers.

Effect of season and supplementation on the utilization of natural herbage by grazing calves in the wet-intermediate zone of Sri Lanka

A grazing experiment was conducted to determine the production potential of buffaloes as a function of supplementation and pasture production during different seasons. Six groups of two cross-bred Murrah buffalo heifers of 16 ± 3 months of age mean live weight of 127 ± 10 kg were randomized into 0.6ha of coconut land to remain and continuously graze the herbage from Jan 2004 to Jan 2005. The treatments were: (T1) Natural herbage; (T2) T1+ supplement (rice bran/molasses/urea/mineral mixture) + Gliricia sepium (3-5kg / day). Dry matter (DM) yields were not only influenced by the seasons, but were also related linearly to the seasonal rainfall. The DM yield and CP content increased towards the end of the experiment in T2 as compared to T1. The average daily gain and total gain of both treatments were linearly related to the DM yield and ranged from 297 kg/head/ha for T1 and 446 kg /head/ ha for T2. It is concluded that season had a significant influence on ruminant production under natural grazing conditions. Supplementation could compensate the seasonal fluctuations in grazed herbage.

Effect of diet with different energy content in growing Murrah buffalo heifers

The relationship between variations of weight and BCS was evaluated using growing buffalo heifers, fed diets with different energy level. 12 Murrah bred heifers (age: 790 days, LW: 400 kg), raised in Saint Paul (Brazil) were equally divided in group H and L fed diets with 5.8 UFL/day and 3.6 UFL/day, respectively. At the end of treatment, groups showed significant differences in weight and values of BCS. In this trial each point of BCS, in Murrah heifers, seems to be equivalent to an increase and/or a loss of about 50 kg of live weight. During this trial the mean value of daily weight gain (DWG) was significantly higher in group H (310 g. vs 0 g.; P<0.01). The heifers of group H required 5.4 UFL to increase the live weight, while group L showed a constant live weight in spite of the assumption of energy level of diet not sufficient to satisfy the requirements of weight maintenance. As it is known, buffalo heifers improves the efficiency of the diet utilization in case of deficiency and wastes energy when receiving diet with high energy content.

Seasonal variation and circadian rhythmicity of the prolactin profile during the summer months in repeat-breeding Murrah buffalo heifers

The present study was undertaken to determine a detailed endocrine profile for prolactin and progesterone during the oestrous cycle in repeat-breeding Murrah buffalo heifers during summer and winter. Hormone concentrations were quantified in blood plasma samples collected over the oestrous cycle in both winter and summer, as well as in samples collected during the summer months to observe circadian rhythmicity. The mean plasma prolactin concentration during the winter months ranged from 3.10 +/- 0.48 to 9.17 +/- 1.39 ng mL(-1); during the summer months, plasma prolactin concentrations ranged from 248.50 +/- 16.03 to 369.63 +/- 25.13 ng mL(-1). During the winter months, the mean plasma progesterone concentration ranged from 0.20 +/- 0.00 to 3.04 +/- 0.34 ng mL(-1), which was significantly higher (P < 0.01) than the prolactin concentrations recorded in the summer months (range 0.20 +/- 0.00 to 1.48 +/- 0.13 ng mL(-1)). Plasma prolactin and progesterone concentrations were negatively correlated (r = -0.24) during the summer oestrous cycle, which indicates prolactin-induced suppression of progesterone secretion through poor luteal development. During the summer, a circadian rhythmicity was observed in buffaloes and the results indicate that high prolactin secretion contributes to poor fertility by lowering gonadal hormone (progesterone) secretion. It was concluded from the present study that prolactin and progesterone profiles during the summer and winter months are directly correlated with the reproductive performance of buffaloes. The finding also validates the hypothesis that hyperprolactinaemia may cause acyclicity/infertility in buffaloes during the summer months due to severe heat stress.

Effect of catecholamines and thermal exposure on lymphocyte proliferation, IL–1α & β in buffaloes

In order to study the effect of catecholamines (epinephrine/norepinephrine) and thermal exposure on in vitro buffalo Lymphocyte Proliferation (LP) apparently healthy 2- 2 1/2 years old Murrah buffalo heifers maintained as per the standard feeding and management practices were selected from Institute herd. Jugular blood was collected in the forenoon on the day of experiment and processed for Total Leucocyte Count (TLC) and Differential Leucocyte Count (DLC). Lymphocyte proliferation assays were performed using whole blood and cells were incubated with epinephrine and norepinephrine (1, 1.5,2 ng/ml) at 37oC with 5% CO2. Cells were counted after 72 hrs of incubation and Lymphocyte Proliferation Index (LPI) was calculated. Thermal stress effect on the cultures was observed after exposure at 45oC for 4 hr after 72hrs of incubation. The cells were separated from media and media was used for analysis of IL-1α & 1β by ELISA kit. Lymphocyte proliferation Index decreased in responses to Epinephrine and Norepinephrine (P<0.01). Concentration of epinephrine and norepinephrine (1, 1.5,2 ng /ml) had no distinguishable effect on LPI. IL-1α & IL-1β levels when compared with control in supernatant (exposed to 45°C) were low (P<0.01 and P<0.05, respectively). There was a significant positive correlation between LPI and IL-1α (r=0.80; P<0.01) and between LPI and IL-1β (r=0.78; P<0.05). The study indicated that lymphocyte proliferation in vitro and IL-1α & β levels were affected by catecholamines and thermal exposure. Further the levels of catecholamines had significant (P<0.01) negative effect on LPI indicating that catecholamines levels modulate immunity through IL-1α and IL-1β in buffaloes.

Effects of growth hormone-releasing factor on growth hormone response, growth and feed conversion efficiency in buffalo heifers ( Bubalus bubalis)

The aim of this study was to determine the benefits of growth hormone-releasing factor (GRF) on growth and feed conversion efficiency (FCE) in buffaloes. Twelve Murrah buffalo heifers ( Bubalus bubalis) of mean age 24.8 months and mean body weight 302.4 kg were divided into two groups (treatment and control) with six animals in each group. The buffaloes were given intravenous injections of bovine GRF (bGRF) at a dose rate of 10 μg/100 kg body weight or an equal volume of saline at 15-day intervals for a period of 9 months. Plasma growth hormone (GH) responses to bGRF challenge were measured in blood samples collected at 90-day intervals on days 1, 90, 180 and 270 and samples were taken at −60, −30, 0, +10, +20, +30, +60, +120 and +180 min relative to bGRF injection. Blood samples were also collected weekly by jugular venepuncture for the quantification of plasma GH. The average growth rate (AGR) and FCE of all animals were recorded at 15-day intervals. Plasma GH concentrations increased ( P = 0.001) steadily following bGRF challenge, peaking 10–20 min after challenge and declining to baseline by 180 min. In the treatment group, there were no significant differences ( P > 0.05) in either the peak heights of the GH response or the area under the curve (AUC) of the GH response after bGRF challenge on any of the four occasions of intensive bleeding. There were overall increases in plasma GH concentrations ( P < 0.01), AGR ( P < 0.01) and FCE ( P = 0.05) in the treatment group compared with the control animals. The study showed that GH responsiveness to administration of bGRF at 15-day intervals over 9 months of treatment remained unchanged in buffalo heifers. Exogenous bGRF treatment for a long period can therefore enhance GH release leading to higher growth rates and better feed conversion efficiency in buffalo heifers.

Características da carcaça e da carne de novilhas búfalas terminadas em confinamento, em função do uso de promotor de crescimento ou de esferas de chumbo no útero

Objetivou-se com este trabalho avaliar o efeito da simulação da prenhez (introdução de 100 esferas de chumbo no útero - CHU) e do uso de promotor de crescimento (PRC), em comparação a novilhas testemunhas vazias, porém, com atividade ovariana (novilhas vazias - VAZ) sobre o peso de carcaça, a conformação da carcaça, os comprimentos de carcaça e de perna, as espessuras do coxão e da gordura de cobertura, as proporções de osso, músculo e gordura e as perdas ao descongelamento e à cocção. Foram utilizadas 20 novilhas bubalinas da raça Murrah com média de 20 meses de idade. Após período de confinamento (84 dias), foram registrados pesos médios ao abate (PVA) de 422,6 kg, para as novilhas do tratamento VAZ; 414,9 kg, para as do tratamento CHU; e 451,8 kg, para as do tratamento PRC. Não houve diferença entre tratamentos para o peso vivo ao abate (429,8 kg), peso de carcaça quente (209,0 kg), conformação da carcaça (8,2 pontos), comprimentos de carcaça (122,9 cm) e de perna (68,1 cm), espessuras do coxão (25,0 cm) e da gordura de cobertura (4,8 mm), área de olho de lombo (57,1 cm²), proporções de músculo (60,6%), de osso (18,9%) e de gordura (20,5%), relações músculo/osso (3,2), músculo mais gordura (porção comestível)/osso (4,3), perdas ao descongelamento (9,3%), à cocção (23,4%) e do congelado após a cocção (30,5%), maciez (7,8 pontos), suculência (7,0 pontos) e palatabilidade (6,8 pontos). Concluiu-se que a utilização de promotor do crescimento e de esferas de chumbo no útero não influenciou as variáveis analisadas.

Growth hormone-releasing factor (GRF) induced growth hormone advances puberty in female buffaloes

Exogenous bovine growth hormone-releasing factor (bGRF) at the dose rate of 10 μg/100 kg body weight was administered intravenously (i.v.) to six Murrah buffalo heifers as treatment group, while another six buffalo heifers served as control group which received the vehicle (0.9% NaCl solution) at an interval of 15 days for a period of 9 months to study the effect of bGRF on puberty onset associated with temporal hormonal changes in peri-pubertal buffalo heifers. Blood samples were collected at 3-day interval from all the animals during the experimental period and plasma harvested was assayed for growth hormonal (GH), luteinizing hormone (LH) and progesterone. The day that plasma progesterone was greater than 1.0 ng/ml for three consecutive sampling days was defined as the day of puberty. Exogenous bGRF administration increased ( P = 0.02) plasma GH concentration in treatment group over control group during the treatment of bGRF as well as during the peri-pubertal period. Plasma progesterone concentrations increased transiently earlier ( P = 0.05) by 58.5 days in bGRF-treated buffaloes than that in the control group. However, plasma LH concentrations were unaffected by the treatment of bGRF ( P = 0.48). Both plasma GH and LH in the buffalo heifers increased ( P < 0.01) over time preceding puberty and the higher hormonal concentrations were maintained during the onset of puberty, and thereafter, the concentrations of both the hormones declined ( P < 0.05) after puberty. GH and LH were positively correlated both before puberty ( r = +0.59 and +0.63; P < 0.05 for control and treatment group, respectively) and after puberty ( r = +0.42 and +0.46; P < 0.05 for control and treatment group, respectively) indicating the interaction and/or close relationship of GH and LH in the mechanism of puberty in buffalo species.

Peripheral Patterns of Growth Hormone, Luteinizing Hormone, and Progesterone Before, at, and after Puberty in Buffalo Heifer

Buffalo, the premier dairy animal in India, suffers from slow growth rate, delayed puberty, and silent heat. It is not known whether the delay in puberty in such animals is due to the delay in expression of hypothalamus-pituitary-gonadal functions. To determine the changes in growth hormone (GH), luteinizing hormone (LH), and progesterone before, at, and after puberty of Murrah buffalo heifers, six Murrah buffalo heifers (21.92 61.09 months of age, 269.67 6 7.97 kg body weight) were assigned to well-ventilated individual pens and fed a roughage-concentrate diet to provide weight gain of 0.4 kg/day. Blood samples were collected at 3-day intervals during a period of 12 months, and plasma harvested from blood samples was assayed for progesterone, LH, and GH. The day that plasma progesterone was greater than 1 ng/mL for three consecutive sampling days was defined as the day of puberty. Heifers attained puberty at an average age of 31.53 6 0.88 months with a body weight of 380.67 66.42 kg. Progesterone levels were very low (0.20 to 0.30 ng/mL) during the pre-pubertal period. There were two distinct elevations before the day of puberty onset. Plasma LH and GH concentrations increased (P < 0.05) during the months preceding puberty and were highest during the month before puberty. GH and LH were positively correlated (P < 0.05) prior to (r = +0.59) as well as after puberty (r = +0.42). A positive correlation (P < 0.05) between LH and body weight during the pre-pubertal period (r = +0.61) and thereafter, negative correlation (P < 0.05) during post-pubertal period (r = 20.64) was noted. GH and body weight showed positive correlation both before puberty (r = +0.92, P < 0.01) and after puberty (r = +0.32, P < 0.05). Results suggest that both GH and LH are equally important and vital cues in inducing onset of ovarian functions in buffalo heifers.

Plasma leptin levels in Murrah buffalo heifers fed diet with two different energy levels

RiassuntoLivelli plasmatici di leptina in manze bufaline di razza Murrah alimentate con due differenti livelli energetici. Scopo del lavoro è stato valutare i livelli plasmatici di leptina ed i loro rapporti con le variazioni di peso, BCS, insulina, glucagone, IGF-1, glucosio, colesterolo, trigliceridi e NEFA in manze bufaline in accrescimento, alimentate con diete a differente contenuto energetico. 12 manze di razza Murrah (790 giorni di età e 400 kg di peso), allevate in S .Paolo (Brasile) sono state alimentate con diete differenti per contenuto in UFL: 5,8 UFL/giorno (Gruppo H; n=6) vs. 3,6 UFL/giorno (Gruppo L; n=6). Si sono registrate differenze significative tra i gruppi per il peso a fine prova e per i valori di BCS e di leptina. Sono emerse correlazioni significative tra leptina e incremento di peso corporeo, BCS nonché insulina, glucosio, colesterolo e glucagone ematici. La relazione tra leptina ed IGF-1 è risultata significativa solo dopo la 4a settimana. Relazioni differenti sono emerse analizzando i dati entro i singoli gruppi di alimentazione.

Effects of PGF2α and GnRH during Different Ovarian Status at Onset of Puberty in Murrah Buffalo Heifers (Bubalus bubalis)

Effects of PGF2α and GnRH during Different Ovarian Status at Onset of Puberty in Murrah Buffalo Heifers (Bubalus bubalis)

Effect of FSH-P priming on superovulatory response in buffalo (Bubalus bubalis)

The aim of this study was to determine the benefits of growth hormone-releasing factor (GRF) on growth and feed conversion efficiency (FCE) in buffaloes. Twelve Murrah buffalo heifers (Bubalus bubalis) of mean age 24.8 months and mean body weight 302.4 kg were divided into two groups (treatment and control) with six animals in each group. The buffaloes were given intravenous injections of bovine GRF (bGRF) at a dose rate of 10 μg/100 kg body weight or an equal volume of saline at 15-day intervals for a period of 9 months. Plasma growth hormone (GH) responses to bGRF challenge were measured in blood samples collected at 90-day intervals on days 1, 90, 180 and 270 and samples were taken at −60, −30, 0, +10, +20, +30, +60, +120 and +180 min relative to bGRF injection. Blood samples were also collected weekly by jugular venepuncture for the quantification of plasma GH. The average growth rate (AGR) and FCE of all animals were recorded at 15-day intervals.Plasma GH concentrations increased (P = 0.001) steadily following bGRF challenge, peaking 10–20 min after challenge and declining to baseline by 180 min. In the treatment group, there were no significant differences (P > 0.05) in either the peak heights of the GH response or the area under the curve (AUC) of the GH response after bGRF challenge on any of the four occasions of intensive bleeding. There were overall increases in plasma GH concentrations (P < 0.01), AGR (P < 0.01) and FCE (P = 0.05) in the treatment group compared with the control animals. The study showed that GH responsiveness to administration of bGRF at 15-day intervals over 9 months of treatment remained unchanged in buffalo heifers. Exogenous bGRF treatment for a long period can therefore enhance GH release leading to higher growth rates and better feed conversion efficiency in buffalo heifers.

Induction of estrus and ovulation in non-cyclic buffalo ( [formula omitted][formula omitted]) heifers with progesterone-releasing intravaginal device and pregnant mare serum gonadotrophin and their gonadotrophin profile

A study was undertaken to induce estrus among 15 non-cyclic Murrah buffalo heifers at a relatively early age of 2.5 to 3 yr by progesterone releasing intravaginal device (PRID) application. On Day 13, the PRID was removed and the animals were divided into two groups (A and B). Group B received 1000 IU of pregnant mare serum gonadotrophin (PMSG) intramuscularly (i.m.) immediately after removal of the PRID, whereas Group A was given no further treatment. Circulating gonadotrophin profiles (luteinizing hormone (LH) and follicle stimulating hormone (FSH) were quantified during and after the PRID treatment, as well as during the induced estrous cycle. LH and FSH levels before, during, and after PRID treatment were in the range of 0.5 to 3.0 ng/ml and 10 to 45 ng/ml, respectively, and could be considered basal levels. The peak FSH levels of Group B (PRID + PMSG) during estrus ranged from 69.44 to 337.06 ng/ml, much higher than the levels recorded in Group A (PRID). None of the animals in Group A showed peak LH levels during estrus, whereas two animals in Group B had peak LH levels of 15.84 and 16.93 ng/ml at 0 h and 12 h after detection of estrus. The higher LH and FSH levels obtained in Group B animals compared with Group A animals was possibly due to the superimposed effect of PMSG over PRID. All of the 14 animals exhibited estrus. None of the animals in Group A conceived whereas three out of seven animals in Group B conceived, indicating that PMSG following PRID resulted in ovulatory estrus.

Body size and pelvic area relationships at puberty and two-month-pregnancy in buffalo - heifers

The relationships among body weight, height at hook bone, height at pin bone, hip width, rump length, pin width and pelvic area were estimated in puberal (n=50) and two-month pregnant (n=35) Murrah buffalo-heifers. In both types, significant correlations (P∠0.10) existed among all measurements studied. Averages for pelvic area at puberty and two-month pregnancy were 285.05 and 302.00 sq. cm, respectively. At the time of parturition, no buffalo heifer exhibited dystocia due to narrow pelvic opening.

Studies on oestrous symptoms of buffalo heifers

Studies based on frequent daily observations for nine months, encompassing 92 oestrous periods in 31 Murrah buffalo heifers, revealed that the vulval discharge of clear mucus in varying quantities in a recumbent animal, even in silent heat, was the most reliable single sign of heat in buffalo heifers. Of the other signs observed, wall walking (segregation) and bellowing confirmed oestrus in 83.69% and 80.43%, respectively, while placid response of the animal to the placing of palm of hand on the rump ano response to light massage of vulval lips were seen in 86.95% and 83.69%, respectively. Based upon the degree of manifestation of oestrous symptoms, intensity of oestrus was divided into four categories. Four daily observations of the animal for important symptoms of heat a few days before the expected oestrus could make oestrous detection a sure success.