• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.49-57
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• 1986

Studies were conducted to investigate the relationship between hormone leveles and nutritional levels for improving performance of Cheju native cattle. In June 1984 a trial was initiated using 8 Cheju native calves after weaning, fed at two su, pp.ementary feeding levels (NRC 100% and 70%). The body weight, breedng performence, change in progesterone level during pregnancy and estrus cycle were evaluated. Mean body weight at 6 months of age was 155kg when fed 100% NRC ration but it was only 137kg when heifers received the 70% NRC ration. At 10, 15 and 20 months of age the body weight was 66, 160 and 115kg, respectively, showing that heifers fed the standard ration gained weight rapidly (P<0.01). Average size of the lefe ovary in the standard group was 2.1${\times}$1.6cm and right ovary was 2.6${\times}$1.8cm. However in the restricted feeding group the ovaries were found to be smaller. Diameter of graffian follicles showed a similar tendency to ovarian size in the two groups. The first oestrus in the standard feeding group a, pp.ared at 14.6 months when body weight was 265kg. Age at first calving was on average 28.9 months at a body weight of 436kg. On the other hand when heifers were fed the restricted ration the first oestrus a, pp.ared at 23.0 months at a body weight of 250kg. Average age at first calving was 38.9 months which was 10 months later than the average in the standard feeding group (P<0.01). In standard feeding group the progesterone level was 2.0ng/ml at two weeks after pregnancy and gradully increased up to 4 weeks and peaked at 18 weeks. This peak (6.4-6.5ng/ml) was maintained up to 24 weeks when progesterone level decreased until it reached 2.1ng/ml at the end of pregnancy. In the restricted group progesterone level up to 16 weeks followed a similar pattern to the standard group but there was a tendency in the restricted group to have lower progesterone levels(P<0.01). The standard and srstricted groups showed similar patterns of progesterone concentration during the oestrus cylce. There were no statistically significant differences in progesterone levels between standard and restricted groups but there was variation between induvidual animals.

• Reproductive and Developmental Biology
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• v.41 no.2
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• pp.25-31
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• 2017

Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with $PGF_2{\alpha}$ analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional $PGF_2{\alpha}$ after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of $PGF_2{\alpha}$ and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with $PGF_2{\alpha}$ and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.765-770
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• 2001

Thirty second parity sows of the synthetic Nepalese Pakhribas genotype were used to investigate factors which might improve the occurrence and expression of estrus. The experiment had two sequential elements. In part 1, a change in suckling pattern was applied during lactation, and in part 2, different estrus detection methods were evaluated after weaning. All sows received the same pattern of weaning, which imitated the progressive weaning system used in Nepalese villages. Piglets from each litter were weaned at three ages (6, 7 and 8 weeks of age) in the proportion of 0.5 at 6 weeks followed by 0.25 at each of the subsequent weanings. In the first lactation treatment, the suckling pattern was left undisturbed, similar to the practice used in the villages in which the remaining piglets after first weaning are allowed continuous suckling. In the other treatment, the remaining piglets after first weaning were allowed to suckle their sows only during the night, whilst in the day time (09:00-16:00) they were excluded from the sow but left free to roam around. After weaning, estrus detection procedures were carried out in the absence or presence of two different boar stimuli: a synthetic boar pheromone spray or fresh boar urine. These were applied sequentially in a sequence of testing that alternated for each sow on a daily basis. The weaning to re-mating interval was significantly longer for the unrestricted suckling treatment. All sows were re-mated within 30 days after first weaning in the restricted suckling treatment groups, whereas only 71% of sows were re-mated within 30 days after weaning in the unrestricted suckling treatment groups ($x^2=3.877$, 1df, p<0.05). Both boar pheromone spray and boar urine increased the estrus detection probability, with no significant differences between the two stimuli treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.4
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• pp.427-438
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• 1996

The suitability of female cattle ($Brahman{\times}Holstein$) and buffaloes (Murrah / Jafarabadi) for work on a sugarcane crusher was tested. The animals were fed chopped sugarcane tops and elephant grass supplemented with rice bran and urea-molasses blocks. In experiment 1, six cattle and six buffaloes, (with three animals seven to eight months pregnant at the start of the experiment in each group), worked individually, alternate weeks for 90 minutes a day for 6 d/week. Within the 90 min, cattle did more work than buffaloes (p < 0.05), and non-pregnant animals did more than pregnant animals, but cattle crushed significantly (p < 0.05) more cane per day than buffaloes. During work animals lost weight, but gained the weight back during resting weeks, when fodder intakes were higher. There were no significant differences in live weight change and fodder intakes between pregnant and non-pregnant animals during the six weeks. In experiment 2, four pairs of lactating cows and buffaloes crushed sugarcane for 3 h/d, 6 d/week for three weeks. Work done was higher in cattle than buffaloes, but cane crushed was marginally lower. All animals lost weight during work, particularly in the first week, but gained weight during the week after work. Daily milk yield was lower during the working weeks ($-0.55{\pm}0.15kg$) than in the week before work. Butter fat yield showed no significant change. One buffalo showed ovarian activity and oestrus behaviour during the work. Two cows showed ovarian activity within one month after the work. It was concluded that pregnant and lactating cows and buffaloes can effectively operate a cane crusher, however a temporary reduction in milk yield can be expected in the working period, and ovarian activity may be suppressed.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.463-469
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• 2005

An attempt was made to analyze the factors affecting mating performance of rams in pen mating systems. Due to many types of social interactions, mating performance of rams may decrease or increase. Six intact Muzaffarnagari rams were used and divided into three dominant subordinate pairs by food and ewe competition test. For dominant rams subordinate ram became competitor and vice versa. In the first experiment, ram was exposed to ewe but the competitor ram was kept outside the pen with the facility of visibility only. In the second experiment each ram was exposed to ewe along with the competitor ram and in third experiment ram was exposed to ewes (two) along with competitor ram in observation pen. Recordings of different mating and agonistic behaviour were done in all the experiments. It was found that subordinate ram's mating behaviour was inhibited by mere presence of a dominant ram out side without physical contact. However, when ram exposed to oestrus ewe(s) along with competitor ram, both dominant and subordinate rams spent much of their time in guarding activities instead of mating. In addition dominant ram tried to curtail the subordinate ram mating by agonistic interaction like fight and butting. Different guarding activities were observed either as active or passive type depending on level of dominanace. It was concluded that in a limited space the interaction of two or more rams might affect the number of services adversely.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.404-409
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• 1998

Nine cows were superovulated by administration of 8 injections of Folltropin each (2.5 ml/injection, 1.75 mg/ml) i.m spread over 4 days, beginning on Day 10 of oestrous cycle, and 30 and 20 mg prostaglandin $F_{2{\alpha}}$ was given along with the 5th and 6th injections of Folltropin, respectively, to induce luteolysis. The animals were artificially inseminated 48, 60 and 72 h after the first prostaglandin $F_{2{\alpha}}$ injection. The number of corpora lutea was recorded by palpation per rectum and by ultrasonography on Day 6 (Day 0 = day of oestrus). The ovaries were examined daily by ultrasonography on Days 3-9 of the oestrous cycle for following the growth and regression of the largest follicle, which was considered the morphologically dominant follicle. The animals were classified into two groups depending upon the presence (n = 4) and absence of a dominant follicle (n = 5). There was a high correlation (r = 0.97, p < 0.001) between the number of corpora lutea observed by palpation per rectum and that determined by ultrasonography. Mean (${\pm}SEM$) number of corpora lutea determined by ultrasonography ($11.20{\pm}3.71$ vs $3.25{\pm}0.75$) and by palpation per rectum ($10.40{\pm}3.91$ vs $2.25{\pm}0.75$) was significantly higher (p < 0.05) in the nondominant group compared to that in the dominant group. There was no difference in the numbers of follicles 2-3 mm ($13.80{\pm}4.49$ vs $8.00{\pm}1.08$), 4-6 mm ($7.00{\pm}1.87$ vs $3.50{\pm}1.33$), and the total number of follicles ${\geq}2mm$ ($22.00{\pm}5.95$ vs $12.50{\pm}1.26$) between the two groups, one day prior to initiation of superovulation. There was, however, a significant (p<0.01) positive correlation between the number of corpora lutea with the numbers of follicles 2-3 mm (r = 0.83), 4-6 mm (r = 0.80) and the total number of follicles ${\geq}2mm$ (r = 0.89) observed one day prior to initiation of superovulation. The results of this study indicate that the presence of a dominant follicle adversely affects the superovulatory response in cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.543-548
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• 2002

Fresh elephant grass was replaced by urea treated rice straw (UTRS) to evaluate the effects on milk production of crossed lactating cows. A total of 16 crossbred F1 cows (Holstein Friesian ${\times}$ Vietnamese Local Yellow), with a body weight of about 400 kg and lactation number from three to five, were used in the experiment. The experimental cows were blocked according to the milk yield of the previous eight weeks and divided into 4 homogenous groups. The experiment was conducted with a Latin Square design with 4 treatments and 4 periods. Each period was 4 weeks, with 2 weeks of feed adaptation and 2 weeks for data collection. The ratio of concentrate to roughage in the ration was 50:50. All cows were given constant amounts of elephant grass dry matter (DM), with ratios of 100% grass without UTRS (control treatment 100G), and 75% grass (75G), 50% grass (50G) and 25% grass (25G) with ad libitum UTRS. Daily total DM intake on 100G, 75G, 50G and 25G was 12.04, 12.31, 12.32 and 11.85 kg, and the daily ME intake was 121.6, 121.5, 119.4 and 114.3 MJ, respectively. The daily CP intake was similar for all treatments (1.85-1.91 kg). There was a difference (p<0.05) in daily milk yield between the 25G and the 100G and 75G (11.7 vs. 12.6 and 12.5 kg, respectively). Milk protein concentration was similar for all treatments, while a tendency to increased milk fat concentration following the increase of UTRS ratio was observed. The cows gained 4-5 kg body weight per month and showed first oestrus 3-4 months after calving. The overall feed conversion for milk production was not affected by ratio of UTRS in the ration. It is concluded that replacement of green grass by UTRS with a ratio of 50:50 for crossbred lactating cows is as good as feeding 100% green grass in terms of milk yield, body weight gain and feed conversion. UTRS can preferably replace green grass in daily rations for crossbred dairy cows in winter to cope with the shortage of green grass, with the ratio 1:1.