Number Of Artificial Inseminations Research Articles

Flushing em vacas de corte no pós-parto, submetidas ao desmame precoce: desempenho reprodutivo

The objective of this experiment was to evaluate the effects of short-time fat supple-mentation (flushing) on the reproductive performance (postpartum estrus, postpartum anestrus, postpartum estrus interval, calving interval, number of artificial insemination, artificial insemination interval, and pregnancy rate) of postpartum beef cows, submitted to the early weaning. Two hundred and fifty eight beef cows were used from the following genetic groups: Aberdeen Angus (n= 21), Aberdeen Angus x Canchim (n= 20), Canchim x Aberdeen Angus (n= 52), Charoles x Caracu (n= 29), Charolais (n= 18), Cachim (n= 34), Caracu (n= 35), Caracu x Charoles (n= 26) an Puruna (n= 23), with 418.1 kg of body weight and all pregnant. These animals were split into two types of treatments: flushing (30% soybean full + 70% corn) and no supplementation. There was no flushing effect on postpartum estrus percentage (82.9%), anestrus percentage (17.0%), postpartum estrus interval (100.5 days), calf birth weight (34.2 kg), number of artificial insemination (1.4), interval between the 1st and the 2nd artificial insemination (19.2 days), interval between the 1st and the 2nd artificial insemination (19.9 days), and pregnancy percentage (54.6%). The flushing reduced calving interval (391.14 vs. 399.31 days). The November period had lower postpartum estrus percentage (70.6%), anestrus percentage (29.4%), postpartum estrus interval (90.3 days), calving interval (378.3 days), number of artificial insemination (1.2), interval between the 1st and the 2nd artificial insemination (11.5 days), and pregnancy percentage (27.5%).

Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3–5 weeks post partum, a randomized, double-blind clinical trial

BackgroundDelayed uterine involution has negative effects on the fertility of cows; use of prostaglandin F2alpha alone as a single treatment has not been shown to consistently improve fertility. Combined administration of PGF2alpha and PGE2 increased uterine pressure in healthy cows. We hypothesized, that the combination of both prostaglandins would accelerate uterine involution and have, therefore, a positive effect on fertility variables. In commercial dairy farming, the benefit of a single post partum combined prostaglandin treatment should be demonstrated.Methods383 cows from commercial dairy farms were included in this study. Uterine size and secretion were evaluated at treatment 21–35 days post partum and 14 days later. Cows were randomly allocated to one of three treatment groups: PGF2alpha and PGE2, PGF2alpha or placebo. For every animal participating in the study, the following reproduction variables were recorded: Interval from calving to first insemination, days open, number of artificial inseminations (AI) to conception; subsequent treatment of uterus, subsequent treatment of ovaries. Plasma progesterone level at time of treatment was used as a covariable. For continuous measurements, analysis of variance was performed. Fisher's exact test for categorical non-ordered data and exact Kruskal-Wallis test for ordered data were used; pairwise group comparisons with Bonferroni adjustment of significance level were performed.ResultsThere was no significant difference among treatment groups in uterine size. Furthermore, there was no significant difference among treatments concerning days open, number of AI, and subsequent treatment of uterus and ovaries. Days from calving to first insemination tended to be shorter for cows with low progesterone level given PGF2alpha and PGE2 in combination than for the placebo-group (P = 0.024).ConclusionThe results of this study indicate that the administration of PGF2alpha or a combination of PGF2alpha and PGE2 21 to 35 days post partum had no beneficial effect upon measured fertility variables. The exception was a tendency for a shorter interval from calving to first insemination after administration of the combination of PGF2alpha and PGE2, as compared to the placebo group. Further research should be done in herds with reduced fertility and/or an increased incidence of postpartum vaginal discharge.

Cutaneous basophil hypersensitivity reaction to phytohemagglutinin in repeat breeder cows

In this study the relationship was explored between general immune reactivity, as estimated by the cutaneous basophil hypersensitivity reaction (CBHR) to phytohemagglutinin (PHA), and the level of anti-sperm antibodies of the Ig A and Ig G class in the cervical mucus and sera of cows with different reproductive results. The hypersensitivity test was performed on the day of artificial insemination when cervical mucus and sera samples were also collected. The animals were divided into groups according to the total number of inseminations, number of inseminations per calving and their age. The titer of antibodies was determined by the indirect immunofluorescence method using sperm cells suspended in Tris egg-yolk extender. Our results indicate that the intensity of CBHR is lowest in cows inseminated once or twice and in younger animals, while, there were no differences between the groups when they were formed according to the number of inseminations per calving. Titers of antisperm antibodies (ASA) of the Ig A class in cervical mucus (CM) increased with the number of artificial inseminations, number of inseminations per calving and age of the cows.

Antisperm antibodies of the Ig a class in the cervical mucus and sera of artificially inseminated cows

The aim of this study was to investigate the level of anti-sperm antibodies of the Ig A class in the cervical mucus and sera of artificially inseminated cows. Cervical mucus and sera samples were collected on the day of artificial insemination and the animals were divided into four groups of 20 cows each according to the number of previous inseminations. The titer of antibodies was determined by the indirect immunofluorescence method using sperm cells suspended in Tris egg-yolk extender or the commercial extender "Biociphos +". Our results indicate that titers of antisperm antibodies of the Ig A class elevate with the number of artificial inseminations. Mean titer values were higher in the cervical mucus samples than in sera indicating that the local immune response is more relevant for the immunological reactivity to sperm and extender antigens. In addition, the titer of antisperm antibodies was generally higher when sperm cells suspended in Tris egg-yolk extender were used for the test.

The effect of estrus duration and number of artificial inseminations on fertility of gilts and multiparous sows having a four-day wean-to-estrus interval

Objective: To determine the relationship between duration of estrus (DE) and farrowing rate and litter size of gilts and sows receiving a single or double artificial insemination. Methods: Gilts (n=503) and multiparous sows having a 4-day wean-to-estrus interval (n=901) received either a single or double artificial insemination. Gilts were inseminated the afternoon of the day of detection of their second estrus and, where indicated, again the next morning. Sows were inseminated 24 hours after detection of estrus and, where indicated, again the next morning. Gilts were grouped by DE of <24, 24 to 36, and >36 hours and sows by DE of <36, 36 to 48, and >48 hours. Results: Insemination frequency had no overall effect on farrowing rate of gilts, but within insemination frequencies, farrowing rates were lower in gilts having a longer DE, and, also, those having the longest DE had a lower farrowing rate with a single insemination. Within the entire sow population, and in sows having a DE 36 hours,farrowing rate was lower after a single insemination. Within insemination frequencies, farrowing rates were lower in sows having a longer DE. Litter size was unaffected by insemination frequency or DE in gilts or sows. These results suggest that a single insemination is usually adequate when DE is relatively short, but where a relatively long DE is expected, multiple inseminations are indicated. Before a breeding management protocol is implemented on any farm, average DE should be determined in gilts and in sows having different wean-to-estrus intervals.

Efeito do número de inseminações artificiais sobre a fertilidade de éguas inseminadas com sêmen diluído, resfriado a 14ºC e transportado

Estudou-se o efeito do número de inseminações sobre a fertilidade de éguas inseminadas, três vezes/semana (segundas, quartas e sextas-feiras), com sêmen diluído, resfriado e transportado, de apenas um garanhão. As éguas foram inseminadas a partir da detecção, pela palpação retal, de um folículo de 3,0 a 3,5 cm de diâmetro, em um dos ovários, até a ovulação. Utilizaram-se para o transporte o sêmen diluído no diluidor leite desnatado-glicose e o conteiner "Celle" modificado, sendo a dose inseminante de 400 x 10(6) espermatozóides móveis, no momento da diluição final, pré-resfriamento. De acordo com o número de inseminações artificiais (IA) utilizadas/ciclo, os resultados de 148 ciclos, de 100 éguas, foram agrupados em: 1 IA, 2IA, 3 IA e 4 ou mais IA. A eficiência de prenhez foi de 4,29; 5,04; 5,67; e 3,43, para 1, 2, 3 e 4 ou mais IA, respectivamente. As características foliculares diferiram em relação à freqüência de inseminações com os maiores valores observados no grupo de éguas inseminadas quatro ou mais vezes. Concluiu-se que menor velocidade de crescimento folicular e maior diâmetro do folículo ovulatório estiveram associados a maior número de inseminações artificiais/ciclo. Na presença de uma concentração espermática adequada, o número de inseminações/ciclo não exerceu influência sobre a fertilidade.

Effects of calf breed on milk production and other economic traits of Holstein dams

Production of purebred or crossbred feeder calves for beef, especially HolsteinxJapanese-Black (HxJB) and Japanese-Black (JB), from dairy cattle using artificial insemination or embryo transfer have been used widely in Japan. However, dairy farmers feel uneasy about the effects of calf breed on the economic traits of dams. In this study, those effects were investigated in 798 Holstein heifers bearing Holstein, HxJB, JB or other breed calves. The results of the least-squares ANOVA indicated the effects of calf breed to be significant for gestation length (P<0.01) and calf birth weight (P<0.01) but not for milk yield, fat yield, protein yield, peak yield, day of peak, number of artificial inseminations per pregnancy or days open. Frequency of dystocia was lower in dams bearing HxJB calves than in those bearing Holstein calves (P<0.05). There were no significant differences for frequencies of still birth, retained placenta and subsequent pregnancy. The present data suggest that the effects of calf breed do not place a serious problem on the economic traits of Holstein dams. In conclusion, it is indicated that the production of JB and HxJB feeder calves from Holstein dams does not result in a decrease in dam productivity.

Multivariate analysis of factors associated with calving interval and calving rate in dairy cows

We collected data on reproductive events of cows (n = 2116) that included dates of calving, first service, last artificial insemination before pregnancy examination, pregnancy examination, abortion, diagnosis of cystic ovary, and treatment with prostaglandin. We used multivariate analysis to evaluate the relationship between the interval from insemination to pregnancy examination and the length of calving interval, adjusting for other factors affecting the calving interval. The effect of the interval from insemination to pregnancy examination on calving rate was estimated using logistic regression analysis. The calving interval was long for cows with a short interval from artificial insemination to first pregnancy examination, it was at a minimum at 55 d and increased thereafter. Other factors affecting the calving interval were cystic ovaries, prostaglandin treatment, abortion, number of artificial inseminations, and days to first service. The calving rate was low among cows with a short interval to pregnancy examination, reached a maximum at 48 d, and then declined. Other factors affecting the calving rate were abortion, number of artificial inseminations and whether the cow was bred by a clean-up bull.

The Relationship Between Blood and Fertility Parameters in Post Partum Dairy Cows

The onset of post partum ovarian activity, the number of artificial inseminations (AI) and the time of conception were monitored in 412 Icelandic dairy cows during a period of 3 years. Blood was sampled from the animals at various times after calving and the serum concentration of glucoce, urea, calcium (Ca) and magnesium (Mg) measured. A significant positive correlation was found between the levels of glucose, urea and Ca and the number of days from calving. A significant negative correlation was found between the level of urea and the time of first post partum ovulation. A significant positive correlation was found between the level of glucose and the time of conception. No correlation was found between the blood parameters and the number of AI per animal, the length of first post partum ovarian cycle or the ammount of progesterone found during that cycle. A distinct, although not statistically significant, tendency towards a negative correlation between the level of glucose and the time of first post partum ovulation was found. Our results show that the levels of glucose and urea shortly after parturition do indicate the time of onset of post partum ovarian cyclicity. Our findings indicate that low blood glucose and urea values early post partum lead to subclinical or clinical ketosis which can considerably delay the onset of ovarian activity.