A systems evaluation of high-input management using fortified molasses for beef production in Australia's dry tropics

2009 ◽  
Vol 49 (3) ◽  
pp. 177 ◽  
Author(s):  
Geoffry Fordyce ◽  
Ruth Coates ◽  
Megan Debney ◽  
Stan Haselton ◽  
Robert Rebgetz ◽  
...  
Keyword(s):  
Best Practice ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Price Rise ◽  
High Input ◽  
Net Worth ◽  
Dry Tropics ◽  
Age Cohort ◽  
Beef Producers ◽  
Growth Promotants

The potential of beef producers to profitably produce 500-kg steers at 2.5 years of age in northern Australia’s dry tropics to meet specifications of high-value markets, using a high-input management (HIM) system was examined. HIM included targeted high levels of fortified molasses supplementation, short seasonal mating and the use of growth promotants. Using herds of 300–400 females plus steer progeny at three sites, HIM was compared at a business level to prevailing best-practice, strategic low-input management (SLIM) in which there is a relatively low usage of energy concentrates to supplement pasture intake. The data presented for each breeding-age cohort within management system at each site includes: annual pregnancy rates (range: 14–99%), time of conception, mortalities (range: 0–10%), progeny losses between confirmed pregnancy and weaning (range: 0–29%), and weaning rates (range: 14–92%) over the 2-year observation. Annual changes in weight and relative net worth were calculated for all breeding and non-breeding cohorts. Reasons for outcomes are discussed. Compared with SLIM herds, both weaning weights and annual growth were ≥30 kg higher, enabling 86–100% of HIM steers to exceed 500 kg at 2.5 years of age. Very few contemporary SLIM steers reached this target. HIM was most profitably applied to steers. Where HIM was able to achieve high pregnancy rates in yearlings, its application was recommended in females. Well managed, appropriate HIM systems increased profits by around $15/adult equivalent at prevailing beef and supplement prices. However, a 20% supplement price rise without a commensurate increase in values for young slaughter steers would generally eliminate this advantage. This study demonstrated the complexity of profitable application of research outcomes to commercial business, even when component research suggests that specific strategies may increase growth and reproductive efficiency and/or be more profitable. Because of the higher level of management required, higher costs and returns, and higher susceptibility to market changes and disease, HIM systems should only be applied after SLIM systems are well developed. To increase profitability, any strategy must ultimately either increase steer growth and sale values and/or enable a shift to high pregnancy rates in yearling heifers.

Cooled semen for fixed-time artificial insemination in beef cattle

2016 ◽  
Vol 28 (7) ◽  
pp. 1004 ◽  
Author(s):  
Juliana C. Borges-Silva ◽  
Márcio R. Silva ◽  
Daniel B. Marinho ◽  
Eriklis Nogueira ◽  
Deiler C. Sampaio ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Sperm Motility ◽  
Artificial Insemination ◽  
Egg Yolk ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Sperm Abnormalities ◽  
Hypoosmotic Swelling Test ◽  
Interesting Approach

This study evaluated the use of cooled semen in a fixed-time artificial insemination (FTAI) program compared with frozen–thawed semen to improve pregnancy rates in beef cattle. Ejaculates of three bulls were collected and divided into two treatments: (1) frozen–thawed semen and (2) cooled semen. Egg-yolk extender without glycerol was used for the cooled semen treatment. Straws (25 × 106 spermatozoa) were submitted to cooling for preservation at 5°C for 24 h, after which FTAI was performed. Nelore cows (n = 838) submitted to FTAI were randomly inseminated using frozen–thawed semen or cooled semen. There was a 20% increase in the pregnancy per AI (P AI–1) using cooled semen compared with frozen–thawed semen (59.9 ± 4.7 vs 49.4 ± 5.0%; P < 0.005). There was no difference in P AI–1 among the bulls (P = 0.40). The frozen–thawed semen had fewer functional spermatozoa than did the cooled semen when evaluated by sperm motility (61.7 vs 81.0%), slow thermoresistance test (41.7 vs 66.7%) and hypoosmotic swelling test (38.3 vs 53.7%; P < 0.05). The percentage of sperm abnormalities did not differ between the freeze–thawing and cooling processes (18.6 vs 22.1%; P > 0.05). Because there was less damage to spermatozoa and improvement in P AI–1, the use of cooled semen instead of frozen–thawed semen is an interesting approach to increase reproductive efficiency in cattle submitted to a FTAI protocol.

scholarly journals Calving sub-season and reproductive efficiency of beef cows

2010 ◽  
Vol 39 (10) ◽  
pp. 2182-2186
Author(s):  
Cristiane Reinher ◽  
Júlio Otávio Jardim Barcellos ◽  
Vanessa Peripolli ◽  
Ênio Rosa Prates ◽  
Maria Eugênia Andrighetto Canozzi
Keyword(s):  
Pregnancy Rate ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Climate Variations ◽  
Southern Brazil ◽  
Chi Square ◽  
Chi Square Test

It was evaluated in this work the effect of calving sub-season on the pregnancy rate of 7,726 multiparous Hereford beef cows grazing on natural pastures in southern Brazil, from 1994 to 2007. Calving sub-season periods were divided in 20-day intervals from August 12th to 31st; from September 1st to 20th; from September 21st to October 10th; from October 11th to 31st; from November 1st to 20th. Calving in each sub-season and pregnancy rate (PR) were analyzed by the Chi-square test. Overall means of each sub-season were 92.7% (from August 12th to 31st), 90.6% (from September 1st to 20th), 82.1% (from September 21st to October 10th), 77.7% (from October 11th to 31st), and 70.6% (from November 1st to 20th). Calving sub-season significantly influenced pregnancy rate. Cows which calved in the initial sub-season showed higher pregnancy rates than cows which calved from the fourth calving sub-season. However this difference did not occur in 1999 and in 2007 since calving rates did not statistically differ among the five sub-seasons. In 1998 and 2004, calving rates were lower and the effects of calving sub-season on pregnancy rates were higher, possibly due to climate variations. In general, pregnancy rate decreases as calving occurs later in the year, particularly in years when the weather adversely affects pasture growth.

Reproductive performance of Arab mares in the Kingdom of Saudi Arabia

2014 ◽  
Vol 42 (03) ◽  
pp. 145-149 ◽  
Author(s):  
M. Alamaary ◽  
F. Al-Sobayil ◽  
A. Ali
Keyword(s):  
Saudi Arabia ◽  
Reproductive Performance ◽  
First Record ◽  
Reproductive Activity ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Kingdom Of Saudi Arabia ◽  
Photoperiodic Regulation ◽  
The Mean ◽  
Number Of Cycles

Summary Objective: The aim of this study was to evaluate the reproductive performance of the Arab mares in the Kingdom of Saudi Arabia (KSA). Methods: Managers of 26 studfarms containing 1014 Arab mares at five districts were asked to complete a questionnaire on the reproductive efficiency of their mares. Results: The mean age at first mating was 3.06 ± 0.5 years. Mares were mated equally in winter and all over the year. Natural mating was mostly used (76.9%). The means of estrus duration and estrus interval were 6.58 ± 1 days and 19.57 ± 1.8 days, respectively. The means of first service and overall pregnancy rates and the number of cycles/pregnancy were 52.71 ± 20.2%, 83.72 ± 15.0%, and 1.46 ± 0.3, respectively, with no effect of the postpartum interval, district, or season. The average pregnancy duration was 335.5 ± 10.2 days. It was shorter in mares mated by day 9 postpartum than in those mated later (p < 0.05). The ratio of stallion/mares ranged from 1:4 to 1:24, with no correlation with the pregnancy rates or the number of cycles/pregnancy. Discussion: Photoperiodic regulation and changes in the hypothalamichypophyseal axis of mares are usually associated with the seasonal reproductive activity of mares in the temperate but not in subtropical areas. Short duration of gestation for mares mated by day 9 after foaling may be related to the nutritional status of dams. Conclusion: The obtained data represent the first record of the reproductive performance of Arab mares in the KSA, which could be used to anticipate their performance under different managements. Clinical relevance: The Arab mares in the KSA are not seasonal and can reproduce efficiently all over the year. District and season did not influence the fertility.

8 EFFECT OF CIRCULATING LEPTIN LEVELS AT SYNCHRONIZATION ON SUBSEQUENT FIXED-TIMED ARTIFICIAL INSEMINATION PREGNANCY RATES IN CROSSBRED BEEF HEIFERS

2009 ◽  
Vol 21 (1) ◽  
pp. 104
Author(s):  
G. T. Gentry ◽  
J. A. Pitchford ◽  
M. Chiasson ◽  
L. R. Gentry ◽  
K. R. Bondioli ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Management Practices ◽  
Reproductive Tract ◽  
Body Condition Score ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Limiting Factor ◽  
Metabolic Efficiency ◽  
Beef Heifers ◽  
Plasma Leptin

It is generally accepted that reproductive efficiency is the limiting factor in the profitability of most livestock operations. The heritabilities of reproductive traits are typically low, so most advances in reproductive efficiency must be achieved through changes in management practices. Recent research indicates that leptin may play a role in the reproductive processes for many domesticated livestock species. Leptin has been shown to affect nutrient intake, metabolic efficiency, and animal adiposity, and may be associated with age at puberty onset and the length of the postpartum interval in cattle. Therefore, the objective of this study was to determine whether circulating leptin concentrations during estrous synchronization would affect subsequent pregnancy rates after fixed-timed AI (FTAI) in crossbred beef heifers. Before the initiation of the spring breeding season, 54 crossbred (Red Angus × Simmental) long yearling heifers, averaging 326 ± 6.3 kg with a mean body condition score (BCS) of 5.2 ± 0.33, a mean reproductive tract score of 2.1 ± 0.57, and a mean ovary score of 2.7 ± 0.76, were synchronized with a controlled internal drug-release (CIDR) vaginal implant and 2 mg of estradiol benzoate (EB) on Day 0, a 25-mg injection of prostaglandin and CIDR removal on Day 7, and 2 mg of EB on Day 8, with FTAI occurring 52 hours post-CIDR removal. Blood samples were collected via jugular venipuncture 4 times: twice during the synchronization protocol starting 2 days post-CIDR insertion, once at insemination, and once 4 days after insemination. All females were inseminated with frozen–thawed semen from the same fertile bull. Pregnancy was determined 45 days postinsemination via transrectal ultrasonography. Twenty females (37%) were confirmed pregnant to FTAI. There was no difference in average weights (324 ± 6.6 v. 323 ± 3.7 kg), BCS (5.1 ± 0.1 v. 5.2 ± 0.07), reproductive tract scores (2.2 ± 0.5 v. 2.1 ± 0.5) or ovary scores (2.7 ± 0.2 v. 2.7 ± 0.1) for the pregnant and nonpregnant females, respectively. However, those females that were pregnant from FTAI had higher (P = 0.02) mean plasma leptin concentrations (3.33 ± 0.22 ng mL–1) compared with heifers that did not conceive to FTAI (2.66 ± 0.19 ng mL–1) across all sampling days. In addition, as early as 2 days post-CIDR insertion, females that became pregnant from FTAI tended to have higher (P = 0.13) plasma leptin concentrations (2.76 ± 0.18 ng mL–1) compared with those heifers that did not conceive to FTAI (2.19 ± 0.15 ng mL–1). These results indicate that circulating plasma leptin levels in beef cattle during synchronization may be associated with subsequent fertility and might be a useful tool to select females to increase the efficacy of FTAI protocols in beef cattle.

scholarly journals Factors That Optimize Reproductive Efficiency in Dairy Herds with an Emphasis on Timed Artificial Insemination Programs

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 301
Author(s):  
Carlos Eduardo Cardoso Consentini ◽  
Milo Charles Wiltbank ◽  
Roberto Sartori
Keyword(s):  
Artificial Insemination ◽  
Body Condition Score ◽  
Management Program ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Service Rate ◽  
Dairy Herds ◽  
High Fertility ◽  
Reproductive Management ◽  
Timed Artificial Insemination

Reproductive efficiency is closely tied to the profitability of dairy herds, and therefore successful dairy operations seek to achieve high 21-day pregnancy rates in order to reduce the calving interval and days in milk of the herd. There are various factors that impact reproductive performance, including the specific reproductive management program, body condition score loss and nutritional management, genetics of the cows, and the cow comfort provided by the facilities and management programs. To achieve high 21-day pregnancy rates, the service rate and pregnancy per artificial insemination (P/AI) should be increased. Currently, there are adjustments in timed artificial insemination (TAI) protocols and use of presynchronization programs that can increase P/AI, even to the point that fertility is higher with some TAI programs as compared with AI after standing estrus. Implementation of a systematic reproductive management program that utilizes efficient TAI programs with optimized management strategies can produce high reproductive indexes combined with healthy cows having high milk production termed “the high fertility cycle”. The scientific results that underlie these concepts are presented in this manuscript along with how these ideas can be practically implemented to improve reproductive efficiency on commercial dairy operations.

EFFECTS OF UTERINE INFUSION OF NONVIABLE SEMEN, SEMINAL PLASMA OR EGG ALBUMEN PRIOR TO BREEDING ON THE REPRODUCTIVE EFFICIENCY OF GILTS OR SOWS

1990 ◽  
Vol 70 (1) ◽  
pp. 129-133 ◽  
Author(s):  
J. R. GILES ◽  
L. H. THOMPSON ◽  
S. ARKINS ◽  
T. CAMACHO ◽  
P. A. EICHEN
Keyword(s):  
Litter Size ◽  
Seminal Plasma ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Post Partum ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Corpora Lutea ◽  
Treatment Groups ◽  
Egg Albumen

In two different experiments crossbred gilts and(or) sows were used to investigate the effects of uterine exposure (prior to breeding) to nonviable semen (NS), seminal plasma (SP) or egg albumen (EA) on reproductive performance. Treatment solutions were infused via the cervix at estrus in gilts or within 2 d post-partum in sows. Females were artificially inseminated at the subsequent estrus. In the first experiment pregnancy rates for gilts infused with Beltsville Thawing Solution (BTS) as controls, NS or EA and subsequently inseminated, were 76, 85 and 54%, respectively, and were not significantly different among treatment groups. The number of total embryos (adjusted for number of corpora lutea) present at 38 d postinsemination was 9.6, 9.0 and 9.6, respectively, for BTS, ND and EA infused gilts and was not significantly different. Likewise, the number of live and dead embryos was not different among treatments. In the second experiment, the proportions of inseminated sows infused with BTS, NS or SP that subsequently farrowed were 87, 84 and 92%, respectively, and did not differ significantly among treatments. No significant differences were detected for the number of total, live or dead pigs born per litter among treatments. We conclude that uterine exposure to seminal proteins or egg albumen prior to breeding does not alter reproductive performance in gilts by 38 d of gestation. Also, the infusion of seminal proteins in sows shortly after parturition does not affect pregnancy rates or litter size at the subsequent farrowing. Key words: Reproductive efficiency, litter size, swine, artificial insemination

scholarly journals Fertility response of lactating dairy cows subjected to three different breeding programs under subtropical conditions

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Abdeltawab Abdelrazek Yassin Khalil
Keyword(s):  
Pregnancy Rate ◽  
Treatment Success ◽  
Pregnancy Rates ◽  
Seasonal Effect ◽  
Reproductive Efficiency ◽  
Ovarian Cysts ◽  
Breeding Programs ◽  
Efficient Treatment ◽  
Release Device ◽  
Synchronization Protocol

Abstract Background It is comprehensively recognized that reduced reproductive efficiency represents a great economic loss to dairy producers. Ovarian cysts and anestrus syndromes are considered the greatest significant causes of low reproductive efficiency in dairy herds worldwide as they detrimentally affect the longevity and profitability of dairy herd. Pregnancy rate is the best available single deciding parameter used for assessment of the reproductive efficiency at the herd level which measures the probability that open cows become pregnant per unit of time. So, the current study was planned to evaluate the suitability of using Ovsynch plus CIDR and G6G resynchronization protocols as an efficient treatment regimen for cystic ovarian diseased cows and anestrus cows, respectively, through comparing pregnancy rates of cystic ovarian diseased cows that subjected to Ovsynch supplemented with controlled internal drug release device with the pregnancy rate of healthy cows that subjected to a Presynch-Ovsynch synchronization protocol, as well as through comparing pregnancy rates of anestrus cows that subjected to G6G treatment protocol with the pregnancy rate of healthy cows. Moreover, possible factors such as breed, parity, and season which may affect the treatment success were also evaluated. Results The results of the current study revealed an overall mean pregnancy rate of 36.64%. Moreover, Simmental cows recorded a greater (p < 0.01) pregnancy rate (45.16%) than that recorded for Holstein cows (34.98%). A highly significant seasonal effect was observed, as a higher (p < 0.01) pregnancy rate was recorded for cows inseminated during cold months (39.54%) compared with that recorded for cows inseminated during hot months (29.18%). Conclusions No significant differences were detected in the pregnancy rates among the three breeding programs; thence, the application of the G6G synchronization protocol for anestrus cows and Ovsynch-CIDR synchronization protocol for cows with ovarian cysts could be used as effective treatment regimens as they resulted in nearly the same pregnancy rates that recorded for healthy cows. In addition, the treatment response was highly influenced by cow’s breed, parity, and season of breeding.

scholarly journals Reproductive efficiency Nellore and crossbred cows submitted to administration of melengestrol acetate (MGA) after FTAI protocols

2020 ◽  
Vol 9 (10) ◽  
pp. e5679108897
Author(s):  
Alan Gabriel Valero ◽  
Carlos Renato de Freitas Guaitolini ◽  
Andre Maciel Crespilho ◽  
Gabriela Passamani da Cruz ◽  
Marcio Luiz Denck Tramontin ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Breeding Season ◽  
Medroxyprogesterone Acetate ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Pregnancy Rates ◽  
Conception Rate ◽  
Reproductive Efficiency ◽  
Crossbred Cows ◽  
Melengestrol Acetate

This study aimed to evaluate the influence of medroxyprogesterone acetate (MGA) supplementation between the 13th and 20th day after Fixed-Time-Artificial Insemination (FTAI), on the conception and gestation rates of Nellore and crossbred cows (Nellore x Angus), pluriparous and lactating. For the study, 349 Nellore cows and 270 crossbred cows were selected, distributed into 1) group G1 (n=176): Nellore cows submitted to the FTAI protocol, without MGA supplementation; 2) group G2 (n=173): Nellore cows submitted to the FTAI protocol, with supplementation for 7 days of MGA® (0.28g/AU/day) from the 13th post-FTAI; 3) group G3 (n=119): crossbred cows: FTAI protocol, without MGA supplementation; 4) group G4 (n=151): crossbred cows: FTAI protocol followed by MGA supplementation for 7 days (0.28g/AU/day), from the 13th to the 20th day after FTAI. For statistical analysis, the procedures MIXED and GLIMMIX from SAS were used. G3 had higher rates of conception (CR=85.7%) and pregnancy (PR=95.8%) at the end of the breeding season (P<0.05), without the interference of supplementation with MGA (P>0.05). G1 females had a lower conception rate (TC=76.7%) (P<0.05), with the use of MGA® (CR-MGA=59.5%), but similar rates of pregnancy (PR=90.3%; PR-MGA=92.5%) to the G2, at the end of the breeding season (P>0.05). When G2 and G4 were compared, we found that crossbred females supplemented had higher rates of conception and pregnancy. In conclusion, crossbred animals have higher conception and pregnancy rates at the end of the breeding season. Besides, we found that Nellore females had a lower conception rate, with the use of MGA® Premix.

19 THE EFFECT OF FOLLICLE-STIMULATING HORMONE IN A MODIFIED CO-SYNCH SYNCHRONIZATION PROTOCOL ON SUBSEQUENT PREGNANCY RATES OF CROSSBRED LACTATING BEEF CATTLE

2013 ◽  
Vol 25 (1) ◽  
pp. 156
Author(s):  
L. R. Gentry ◽  
R. W. Walker ◽  
J. Lambe-Steinmiller ◽  
R. A. Godke ◽  
G. T. Gentry
Keyword(s):  
Treatment Group ◽  
Beef Cattle ◽  
Pregnancy Rate ◽  
Beef Cows ◽  
Subsequent Pregnancy ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Follicular Waves ◽  
Estrus Detection ◽  
Synchronization Protocol

Heritability of reproductive traits is relatively low, leaving only management strategies as an alternative to affect reproductive efficiency in beef cattle. The use of assisted reproductive technologies such as fixed-timed AI (FTAI) offers the ability to increase reproductive efficiency through selection of superior genetics and manipulation of calving dates through estrous-synchronization protocols. Application of these technologies has not been fully embraced by cattlemen due to variation in success rate, primarily associated with the apparent lack of control of follicular waves. While it has been reported that an endogenous increase in FSH precedes the emergence of follicular waves in cattle, we could find no reports on the effects of exogenous FSH on FTAI pregnancy rates. Artificial insemination remains the most important reproductive technology that could positively affect cattlemen. Therefore, this experiment was conducted to test the hypothesis that incorporation of FSH into the CO-Synch synchronization protocol would increase FTAI pregnancy rates in beef cattle. Crossbred beef cows (n = 182) with a mean body weight (BW) of 596 ± 6.6 kg and mean body condition score (BCS) of 5.4 ± 0.07 from 3 different locations were stratified across treatment groups by BW, BCS, and days postpartum or cyclicity status based on plasma progesterone concentrations. Females were estrus synchronized using the 7-day CO-Synch+CIDR protocol. All females received a CIDR insert and 100 µg of gonadotropin-releasing hormone (GnRH; Factrel) on Day 0, followed by CIDR removal, 25 mg of prostaglandin (Lutalyse) IM and fitted with an estrus-detection patch (Estrotect) on Day 7. On Day 2, all females (n = 92) in the FSH treatment group were administered 20 mg of FSH (Folltropin) IM and the remaining females (n = 90) served as nontreated controls. Fixed-timed AI was performed at 72 h following CIDR removal when all females were administered 100 µg of GnRH and the estrus-detection patch was evaluated. The overall FTAI pregnancy rate was 55% (100/182) and there was no difference (P = 0.41) in pregnancy rates across locations so the data were pooled and reanalyzed. Pregnancy rates were not affected (P = 0.54) by treatment group and were 52% (48/92) for the FSH-treated females and 58% (52/90) for the nontreated control group. Similarly, based on evaluation of the estrus-detection patch, there was no difference (P = 0.68) in the percentage of females responding to the synchronization protocol [61% (55/92) v. 68% (61/90)] and no difference (P = 0.55) in the pregnancy rate of responding females [62% (34/55) v. 69% (42/61)] for the FSH-treated and nontreated control groups, respectively. In conclusion, administration of FSH 10 days prior to FTAI in CO-Synch+CIDR synchronized crossbred beef cows did not increase subsequent pregnancy rates. However, exogenous FSH administration should be evaluated further to determine its effects, if any, on follicular dynamics related to FTAI in the lactating beef cow.

scholarly journals PERFIL PROTÉICO E EFICIÊNCIA REPRODUTIVA DE VACAS DE CORTE EM LACTAÇÃO SUPLEMENTADAS COM URÉIA NO VERÃO

2004 ◽  
Vol 9 (2) ◽  
Author(s):  
R.M. SOUZA ◽  
A. FILAPPI ◽  
D. PRESTES ◽  
M.A. LISTON ◽  
A. ANTONIAZZI ◽  
...  
Keyword(s):  
Total Protein ◽  
Plasma Levels ◽  
Protein Profile ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Reproductive Efficiency ◽  
Reproduction Performance ◽  
Group A

O objetivo do presente estudo foi mensurar os níveis plasmáticos de proteína plasmática total (PPT), albumina e uréia, hematócrito e escore da condição corporal (ECC), visando avaliar o efeito da suplementação com uréia sobre o perfil protéico e o índice de prenhez (IP) de vacas de corte em lactação, mantidas em campo nativo, durante o período de verão. O experimento ocorreu entre setembro/2002 (primavera) e fevereiro/2003 (verão). As matrizes foram divididas aleatoriamente em dois grupos: controle © n=161) e tratado (T) n=159). Os grupos receberam mistura mineral, porém o T, recebeu adicionalmente 10% de uréia agrícola em janeiro e fevereiro. Relativamente a PPT, não foi observada diferença entre T e C, no verão. Na albumina, não foi observada diferença entre primavera e verão. O C apresentou concentrações maiores no verão do que o T. Os valores do hematócrito, no C de verão foram maiores do que os do C da primavera e T de verão. Na uréia o grupo T, no verão, apresentou níveis maiores do que os C de primavera e verão. Não houve diferença nos ECC entre primavera e verão, assim como entre T e C, no verão. Quanto ao IP, não houve diferença entre C e T. Em conclusão, a uréia tem efeitos deletérios sobre o perfil protéico de vacas de corte com cria ao pé, no verão, quando há alta disponibilidade de massa verde. A adição de uréia à mistura mineral não influência a eficiência reprodutiva das matrizes. Protein profile and reproductive efficiency of lactating beef cows, supplemented with urea during the summer Abstract The objective of the present study was to assay total protein (PPT), albumin and urea plasma levels, hematocrit, body conditions score (BCS) and pregnancy rates (PR) in beef cows supplemented or not with urea during the summer. The experiment started in September (spring) 2002 and ended in February (summer) 2003. The dams were randomly assigned in two experimental groups: control (C; n = 161) and treated (T; n = 159). Both groups received a complete mineral mix. For the T group, a total of 10% of agricultural grade urea was added to the mix during January and February. As a result, no differences in PPT has been observed between both experimental groups during the summer. However, in regard to plasmatic albumin no differences were found for both experimental groups between spring and summer but values showed to be higher for the C group than in T group during summer. There were no differences in BCS nor in IP. The addition of urea to the mineral mix has deleterious effects upon the protein profile os suckling beef cows, when trere is high avalability of forage. The use of urea has no effect on reproduction performance.

Sign in / Sign up

Export Citation Format

Share Document