Effect of cattle tick (Boophilus microplus) infestation on performance of Bos indicus cross cows and their progeny

1988 ◽  
Vol 28 (1) ◽  
pp. 1 ◽  
Author(s):  
RG Holroyd ◽  
PJ Dunster ◽  
PK O'Rourke

The effects of cattle tick infestations on liveweight and fertility of Droughtmaster (1/2 Bos indicus) cows and on calf weaning weights were determined over 3 years. Tick populations on the control (non-dipped) group of cattle fluctuated, with mean annual tick counts/side being 9.5, 8.9 and 13.6 for years 1, 2 and 3 respectively, while the treated group of cattle, which were dipped every 21 days, were free of ticks. Tick counts were not related to fertility or liveweight change in pregnant-lactating cows or to calf growtb or weaning weights. Treatment for ticks significantly (P<0.05) affected liveweight change in pregnant-lactating cows on only a few occasions, and annual liveweight changes were not significantly influenced by treatment. When lactating cow pregnancy rates were low (< 30% for control cows), treatment for ticks increased the pregnancy rate by about 100% in 2 of the 3 years, these differences being significant only in the last year. Calves in the treated group were born significantly earlier in the first year and had significantly lighter birth weights in the third year. Treated calves grew faster to weaning and had higher weaning weights (mean difference 17.9 kg) than control calves but differences were significant in the first and third years only.

2020 ◽  
Vol 48 ◽  
Author(s):  
Caio Cezar Da Silva ◽  
Hélton Aparecido Garcia Gregianini ◽  
Jennifer Teodoro Ferreira Gregianini ◽  
José Antônio Dell’Aqua Junior ◽  
Jefferson Viana Alves Diniz ◽  
...  

Background: In vitro embryo production (IVEP) allows the spread of superior animal genetics, but pregnancy rates show a high variability with this biotechnique. In the initial stage of pregnancy, progesterone plays a fundamental role in uterine preparation, acting on embryonic growth, implantation, and development. However, on the day of the IVEP transfer to the recipients, progesterone levels may be lower than that expected, influencing the uterine environment and, consequently, the pregnancy rate. Therefore, the objective of this study was to evaluate the pregnancy rate in heifers after the administration of injectable progesterone (P4) in the fixed-time embryo transfer (FTET) protocol.Materials, Methods & Results: The experiment was conducted inside a rural property near the city of Rio Branco, Acre, Brazil. The experimental group consisted of 232 animals, including 78 zebuine (Bos indicus) and 154 mixed (½ blood B. indicus and ½ blood B. taurus) animals, aged between 16 and 24 months, with a mean weight of 300 and 330 kg for zebuine and mixed animals, respectively. The selected animals were previously synchronized using the progesterone-estrogen-prostaglandin-estrogen protocol. Embryo transfer was performed on day 18 of the protocol, which was 9 days after the removal of intravaginal progesterone implant. On day 15 of the protocol, that is, 144 h (6 days) after the device removal, the animals were randomly distributed into two experimental groups: Control Group (CG; 0.5 mL of 0.9% saline solution, intramuscular) and Treated Group (P4G; 0.5 mL of injectable P4, 150 mg, intramuscular). Chi-square test was used for the statistical analysis of the pregnancy rate at a 5% probability. After 23 days of embryo transfer, pregnancy was diagnosed by ultrasonography. The general pregnancy rate, considering all groups (CG and P4G) and breeds included, was 55.17% (128/232). The pregnancy rates of the P4G and CG groups, regardless of breeds, were 55.08% (65/118) and 55.26% (63/114), respectively, with no statistical difference (P = 0.8344). Angus animals presented a similar pregnancy rate in the P4G and CG groups of 54.93% (39/71) and 57.83% (48/83), respectively. Furthermore, similar results were found for the Nellore breed, with no difference in pregnancy rate between the CG (55.81%, 24/43) and P4G (48.57%, 17/35) groups.Discussion: The strategy of using P4 to increase the pregnancy rate is very widespread in fixed-time artificial insemination (FTAI) protocols, although differences still exist. The literature presents zero or negative effects, as in this study, when exogenous P4 was used to increase endogenous P4 concentrations and, consequently, the pregnancy rate. However, some studies demonstrated the beneficial effects of increasing blood P4 concentrations, and that the increased fertility depends on the method and time of P4 supplementation and the animal’s physiological state. In this context, the fact that the injectable progesterone supplementation did not increase the pregnancy rate in this study is justified mainly by factors such as the animal category used (heifers), time of P4 supplementation (day 4 after ovulation), biotechnology used (FTET), and the heterogeneous characteristics related to phases of the estrous cycle of heifers. Supplementation with 150 mg of injectable long-acting progesterone intramuscularly did not interfere in the pregnancy rate of Angus and Nellore heifers receiving bovine embryos.


2010 ◽  
Vol 50 (6) ◽  
pp. 345 ◽  
Author(s):  
T. J. Schatz ◽  
G. A. Jayawardhana ◽  
R. Golding ◽  
M. N. Hearnden

The performance of heifers from a Brahman herd that was selected for fertility was compared with Brahman heifers sourced from commercial properties using three year-groups of heifers. Each year, conception rates from yearling mating were significantly higher in heifers from the selected herd (SEL) than in heifers sourced from commercial properties (COM), despite the average joining weight of the SEL heifers being lower each year. The pregnancy rate in SEL heifers was 24% higher (P = 0.008) in the first year, 36% higher (P = 0.005) in the second year and 45% higher (P < 0.001) in the third year. Over the 3 years of the study, the conception rate was 35% higher (P = 0.009) in SEL heifers than in COM heifers. Joining weight also affected pregnancy rates. When heifers were split into weight ranges according to their pre-joining weight, pregnancy rates were significantly higher (P = 0.018) in the heavier weight range than the lighter one. The results indicate that selection for fertility has been successful in improving conception rates from yearling mating in SEL heifers.


1993 ◽  
Vol 44 (7) ◽  
pp. 1509 ◽  
Author(s):  
GP Davis ◽  
NJ Corbet ◽  
MJ Mackinnon ◽  
DJS Hetzel ◽  
KW Entwistle ◽  
...  

Direct response to divergent selection based on estimated breeding value for female pregnancy rate in a herd of Bos indicus cross cattle was evaluated along with correlated responses in calf survival, weaning rate, cow liveweight and calf growth. Pregnancy rates were significantly higher ( P < 0.05) in heifers of the High line compared with the Low line (High-Low=15� 5%) and in lactating 4-year-old cows (25�9.5%) and in 3 of the 5 years of the study (average difference 24%). The Low line had significantly ( P < 0.05) higher pregnancy rates in 1 year (-16�5.4%). These differences in pregnancy rates were reflected in weaning rates, but calf survival was only different between the lines in 2 of the 4 years analysed (-6� 3.0% in 1990 and 18�6.5% in 1991). The High line had a significantly ( P < 0.05) shorter days to calving than the Low line in heifers (High=309�2.2 days v. Low= 315�2.5 days), lactating 3-year-old cows (3l5� 3.6 days v. 331�4.1 days), non-lactating 3-year-old cows (301�5.4 days v. 320�4.6 days) and lactating 4-year-old cows (311�3.9 days v. 336�4.9 days). Differences between the lines in pre-weaning growth varied according to generation with significantly lower (P < 0.05) weaning weights (182�3.1 kg v. 189�3.3 kg) and pre-weaning growth (790�17 g/day v. 826� 17 g/day) in first generation High line calves from foundation dams and no difference between the lines in second generation calves from first generation dams. Post-weaning growth was significantly higher ( P < 0.05) in High line calves (350� 5 g/day v. 327�5 g/day). The results indicate that selection of sires on EBV for pregnancy rate leads to improved fertility in heifers and 4-year-old lactating cows without adverse effects on progeny growth.


2008 ◽  
Vol 126 (1-2) ◽  
pp. 110-119 ◽  
Author(s):  
Emily K. Piper ◽  
Louise A. Jackson ◽  
Neil H. Bagnall ◽  
Kritaya K. Kongsuwan ◽  
Ala E. Lew ◽  
...  

1975 ◽  
Vol 26 (6) ◽  
pp. 1073 ◽  
Author(s):  
BM Wagland

Four purebred Brahman and four beef Shorthorn cattle which had not previously been exposed to Boophilus microplus were infested four times with 20,000 B. microplus larvae. On first infestation, the yield of engorged female ticks on all animals was about 25% of the larvae applied. Aftcr three further infestations, the mean yield of engorged females on the Brahmans decreased to 7.5% whereas there was no decrease in the yield of ticks on the Shorthorns. On the Brahman cattle. development of larvae to engorged females took 1–2 days longer and the engorged females weighed less. However, there was no difference in the reproductive index of female ticks engorged on either Brahmans or Shorthorns. Increases in rectal temperatures occurred in all cattle 15–17 days after the first infestation and in some cattle on days 6–7 as well as on days 15–17 after reinfestation. It was concluded that resistance to B. microplus is an acquired phenomenon in Brahman cattle.


1971 ◽  
Vol 22 (2) ◽  
pp. 331 ◽  
Author(s):  
RW Hewetson

Purebred Sahiwal cattle acquired resistance to Boophilus microplus in a similar manner to crossbred Sahiwal cattle as previously reported. The purebred entire males and females were more resistant than a control group of crossbred steers because they dropped significantly fewer replete ticks than the crossbreds at the third and fourth, but not at the first and second infestations. Adult female ticks dropped by purebred animals were significantly lighter than those dropped by crossbred animals at the fourth infestation only. There was no significant difference in the numbers of eggs laid and hatched from ticks dropped by purebred and crossbred animals. Australian Illawarra Shorthorn steers developed resistance at a second and third infestation which waned at a fourth infestation, but individual steers displayed developing resistance throughout the four infestations. Day of modal drop of replete female ticks appeared to be affected by breed, and developing resistance or season.


1970 ◽  
Vol 21 (1) ◽  
pp. 163 ◽  
Author(s):  
RH Wharton ◽  
KBW Utech ◽  
HG Turner

An Australian Illawarra Shorthorn herd of 24 cows was mated in three consecutive years with an AIS bull. The cows and their progeny were rated for tick resistance at frequent intervals from August 1959 to December 1965 by counting the numbers of semiengorged female ticks on the right side. The mean of log counts for all counts on a particular animal was adopted as the reference value for its degree of susceptibility. The ranking of cattle generally showed a high level of consistency with mean repeatability of counts (r = 0.47, P < 0.01). Discrimination between animals was more reliable (P < 0.01) in summer (r = 0.52) than in winter (r = 0.27). The repeatability of tick counts increased with mean count, from r = 0.27 when the mean count was 3 to r = 0.67 when it was 100. The reliability of counts on the cows decreased with age and with lactation. Supplementary information on a larger herd showed no effect of pregnancy on mean count or on discrimination between susceptible and resistant animals, but showed that there was a partial breakdown of resistance during lactation. In calves infested naturally, no effects of age or sex on tick counts or their repeatability were detected, though male calves yielded significantly larger numbers of ticks than females when infested artificially. The mean yield of mature female ticks on the cows following two artificial infestations with known numbers of larvae ranged from 0.2 to 27.4% of the potential. Natural and artificial assessments of susceptibility were closely correlated. The rank of the bull was similar to that of the more resistant cows. Mean estimates of the heritability of tick resistance based on single counts were 39 % from dam-calf correlations and 49 % from full-sib correlations. Estimates based on summer counts only were 42 and 64% respectively. These results provide strong encouragement for selecting for tick resistance.


2007 ◽  
Vol 19 (1) ◽  
pp. 197
Author(s):  
A. Guzeloglu ◽  
H. Erdem

We previously reported that administration of flunixin meglumine two times at a critical stage approaching pregnancy recognition associated with corpus luteum maintenance increased early embryo survival and pregnancy rate via an additive antiluteolytic effect with the conceptus (Guzeloglu et al. 2006 Reprod. Fertil. Dev. 18, 183). In this study, the objective was to determine if a single administration of meloxicam, a non-steroid anti-inflammatory drug (NSAID) with a longer half-life, could be used instead of flunixin meglumine to avoid repeated injections in heifers at a critical stage following insemination to increase pregnancy rate due to its inhibitory effect on PGF2� synthesis. Eighty-five 15-18-month-old Holstein heifers were synchronized; following insemination (Day 0), the heifers were randomly assigned to receive a subcutaneous meloxicam injection (0.5 mg kg-1; n = 37) in the afternoon of Day 15 or left untreated as controls (n = 48). Pregnancy rates were defined as the percentage of heifers diagnosed pregnant by ultrasound between Days 31 and 38 after AI. The effect of treatment on pregnancy rates was analyzed by chi-square test. Meloxicam treatment on Day 15 after insemination dramatically decreased the pregnancy rates in the heifers (25 of 48 (52%) in the control group vs. 9 of 37 (24.3%) in the meloxicam-treated group; P &lt; 0.01). This result indicates that administration of meloxicam around a time associated with pregnancy recognition and corpus luteum maintenance was harmful to the pregnancy even though the drug is considered to be safe during pregnancy in cattle. It is concluded that direct or indirect effects of meloxicam on the uterine environment and/or embryo are not favorable at least during early pregnancy in cattle. How meloxicam exerted its detrimental effect on pregnancy warrants further investigation.


2015 ◽  
Vol 27 (1) ◽  
pp. 210
Author(s):  
L. F. Feres ◽  
L. S. A. Camargo ◽  
M. P. Palhao ◽  
F. Z. Brandao ◽  
J. H. M. Viana

Improving in vitro culture systems to optimize embryo yield has been a major research goal. The relationship between the efficiency of embryo production systems and the pregnancy outcomes, however, remain controversial. The aim of the present study was to evaluate the likelihood of pregnancy of in vitro-produced embryos derived from batches with different relative efficiency indexes. Data of 702 ovum pick-up (OPU) and in vitro embryo production (IVEP) sessions, and of 2456 embryo transfers, recorded from 2008 to 2012, were evaluated. All donors were from the same herd, and were of the same breed (Gir, Bos indicus), as well as the semen used for IVF. The cumulus-oocycte complex (COC) recovery and IVEP were performed by the same team, in a single IVF laboratory, and using standard medium and procedures. Only data from embryos transferred as fresh were used, and records from 97 OPU/IVEP sessions in which no embryo was produced, or embryos were frozen or discharged due to lack of recipients, were discharged. The remaining 605 sessions were stratified in quartiles (I to IV, each one corresponding to 25% of total data) according to COC production of the donors, or stratified in ranges (0–25%, 26–50%, 51–75%, and 76–100%) according to COC quality (percentage of viable COC or of grade I COC) and to embryo production efficiency endpoints (cleavage rate, blastocyst rate). Pregnancy rates were compared among quartiles or ranges by the chi-square method. On average, the Gir donors produced 24.8 ± 0.6 COC per OPU, from which 14.4 ± 0.4 were classified as viable (57.8%), and 3.2 ± 0.1 as grade I (12.9%). On average 6.1 ± 0.2 embryos (morulas and blastocysts) were produced per OPU per donor, and mean pregnancy rate was 30.9%. As expected, donors with greater total COC yield (quartile I) also produced more viable oocytes (25.5 ± 0.7 v. 15.7 ± 0.3, 10.5 ± 0.2 and 5.8 ± 0.2), more COC grade I (4.8 ± 0.4 v. 3.9 ± 0.3, 2.6 ± 0.2 and 1.6 ± 0.1), and more embryos (9.0 ± 0.4 v. 6.9 ± 0.3, 5.0 ± 0.2 and 3.3 ± 0.1) than donors from quartiles II, III, or IV, respectively (P < 0.0001). Nevertheless, there was no difference (P > 0.05) in pregnancy rates for embryos produced from donors ranked in the different quartiles (30.9 v. 29.3, 31.5, and 30.5% for quartiles I to IV, respectively). Similarly, there was no difference (P > 0.05) in the pregnancy rate of embryos derived from OPU sessions in which there was a high or low percentage of viable or grade I COC. In vitro production efficiency (cleavage and blastocyst rates) also had no effect (P > 0.05) on further pregnancy rates. In conclusion, these results suggest that there is no relationship among the average number or quality of the COC recovered by OPU, the efficiency of IVEP, and the likelihood of pregnancy of in vitro-derived embryos.Research was supported by Fazendas do Basa, CNPq, and Fapemig.


2020 ◽  
Vol 32 (2) ◽  
pp. 130
Author(s):  
D. Demetrio ◽  
A. Magalhaes ◽  
M. Oliveira ◽  
R. Santos ◽  
R. Chebel

Maddox Dairy, located in Riverdale, CA, USA, is a Holstein herd that milks 3500 cows with a 305-day mature-equivalent milk production of 12 800 kg, and they have been producing high genetic animals by embryo transfer (ET) since the early 1980s. Invivo-derived embryos from Holstein donors were transferred fresh (grade 1 or 2) or frozen (grade 1), at morula (4), early blastocyst (5), or blastocyst (6) stage, to virgin heifers (VH, natural oestrus, 13-15 months old) or lactating cows (LC, Presynch-Ovsynch, 86 days in milk, first or second lactation) 6 to 9 days after oestrus. Pregnancy diagnosis was done by transrectal ultrasonography at 32-46 days in VH and by the IDEXX PAG test at 30 days in LC. June, July, August, September, and October were called critical months (first service AI conception rate drops below 44%) and compared with the other months. The data from 32 503 ETs between January 2008 and December 2018 are summarised on Table 1. Pregnancy rates (PR) are lower for LC recipients than for VH. Embryo transfers performed 7 or 8 days after oestrus had higher PR in both types of recipients and embryos, but Day 6 and 9 oestrus are also used with fair results. The season does not seem to affect PR. There is not enough difference in the combination of stage and days from oestrus for invivo-derived embryos. These numbers do not belong to a planned experiment. Several management changes during the years were made, which make it very difficult to apply statistical methods to analyse the data correctly. They are used as a tool to make decisions in an attempt to improve future results. Table 1.Pregnancy rate (PR) of virgin heifers (top) and lactating cows (bottom)-fresh (SH) and frozen (OZ) invivo-derived embryo transfer1 Heat-months SH-ST4 SH-ST5 SH-ST6 SH-All OZ-ST4 OZ-ST5 OZ-ST6 OZ-All PR% n PR% n PR% n PR% n PR% n PR% n PR% n PR% n Heifers 6 d-CM 62 934 66 243 68 69 63 1246 56 473 58 219 62 42 57 734 6 d-OM 62 1623 67 489 69 211 64 2323 56 600 55 296 48 137 55 1033 6 d-T 62 2557 67 732 69 280 63 3569 56 1073 57 515 51 179 56 1767 7 d-CM 64 1506 68 495 67 221 65 2222 60 822 62 340 63 156 61 1318 7 d-OM 66 2723 68 1021 69 510 67 4254 57 1120 59 581 57 231 58 1932 7 d-T 66 4229 68 1516 69 731 67 6476 58 1942 60 921 60 387 59 3250 8 d-CM 65 1348 64 518 67 322 65 2188 59 595 64 258 63 108 61 961 8 d-OM 66 2166 68 886 70 510 67 3562 61 770 60 364 51 130 60 1264 8 d-T 66 3514 67 1404 69 832 66 5750 60 1365 62 622 56 238 60 2225 9 d-CM 60 109 56 43 70 20 60 172 60 5 33 6 50 4 47 15 9 d-OM 58 129 63 57 60 40 60 226 63 16 50 18 75 4 58 38 9 d-T 59 238 60 100 63 60 60 398 62 21 46 24 63 8 55 53 All-CM 64 3897 66 1299 67 632 65 5828 58 1895 61 823 63 310 60 3028 All-OM 65 6641 67 2453 69 1271 66 10 365 58 2506 58 1259 53 502 58 4267 All-T 65 10 538 67 3752 69 1903 66 16 193 58 4401 60 2082 57 812 59 7295 Lactating cows 6 d-CM 54 265 48 86 50 12 53 363 38 141 31 77 50 10 36 228 6 d-OM 49 463 52 203 45 56 50 723 46 101 48 54 59 27 48 182 6 d-T 51 728 51 289 46 68 51 1086 41 242 38 131 57 37 42 410 7 d-CM 54 755 59 274 56 103 55 1137 43 928 48 450 43 192 45 1570 7 d-OM 55 914 66 367 54 109 58 1393 46 1052 45 564 47 353 46 1969 7 d-T 55 1669 63 641 55 212 57 2530 45 1980 46 1014 46 545 45 3539 8 d-CM 63 252 68 82 76 33 65 368 48 219 56 80 42 33 50 332 8 d-OM 61 257 64 161 53 47 61 466 50 191 53 77 56 16 51 284 8 d-T 62 509 65 243 63 80 63 834 49 410 55 157 47 49 50 616 All-CM 56 1272 58 442 60 148 57 1868 44 1288 47 607 43 235 45 2130 All-OM 55 1634 62 731 51 212 56 2582 47 1344 46 695 48 396 47 2435 All-T 55 2906 60 1173 55 360 57 4450 45 2632 47 1302 46 631 46 4565 1ST=stage; CM=critical months (June, July, August, September, and October); OM=other months.


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