scholarly journals Reproductive behavior of crossbred dairy cows grazing an intensive silvopastoral system under tropical dry forest conditions

2017 ◽  
Vol 69 (1) ◽  
pp. 1-9
Author(s):  
E. Sierra-Montoya ◽  
R. Barahona-Rosales ◽  
Z.T. Ruiz-Cortés
Keyword(s):  
Dairy Cows ◽  
Reproductive Performance ◽  
Reproductive Behavior ◽  
Nutrient Intake ◽  
Dry Matter ◽  
Dry Forest ◽  
Ovarian Activity ◽  
Silvopastoral System ◽  
Group 2 ◽  
Group 1

ABSTRACT It is widely accepted that selection for high milk yield in dairy cows has negatively affected their reproductive performance. After calving, dairy cows experience a nutritional imbalance due to an asynchrony in the occurrence of the lactation and dry matter intake peaks. In the tropics, this situation is exacerbated due to poor quality and/ or availability of the diet. A study was carried out to describe the nutritional and reproductive behavior of two-to-four parturition crossbred cows (Gyr (Bos indicus) x Holstein (Bos taurus)) divided in two groups according to their calving to first service interval (CFSI): Group 1: ≤50 days CFSI, n=7; Group 2: ≥50 days CFSI, n=8. Animals were grazing in an intensive silvopastoral system (ISS) based on Leucaena leucocephala and Cynodon plectostachyus and also received protein, energy and mineral supplementation. Dry matter (DMI) and nutrient intake were individually estimated and correlations between reproductive and nutritional parameters were performed. Additionally, serum progesterone concentration was monitored. Group 2 had greater forage and total DMI and milk production than Group 1 (P<0.05). Hence, Group 2 had greater nutrient intake from forages than Group 1 (P<0.05). Group 1 had a positive nutritional balance and an optimum reproductive performance compared to Group 2, which had a negative energy balance and lengthier days with open intervals (P<0.05). It was corroborated that protein and energy are required in adequate levels, to ensure that uterus undergoes involution correctly and ovarian activity starts soon in the postpartum period.

Effect of different diet supplements in the pre- and post-partum period on reproductive performance in the dairy cow

2001 ◽  
Vol 26 (2) ◽  
pp. 313-321 ◽  
Author(s):  
N. H. Gardner ◽  
C. K. Reynolds ◽  
R.H. Phipps ◽  
A.K. Jones ◽  
D.E. Beever
Keyword(s):  
Sugar Beet ◽  
Dairy Cows ◽  
Reproductive Performance ◽  
Post Partum ◽  
Late Gestation ◽  
Diet Supplements ◽  
Group 2 ◽  
The Impact ◽  
Ration Group ◽  
Group 1

AbstractThe study compared the impact of feeding different energy supplements (barley, molassed sugar beet and fat) prior to calving and the effects of feeding supplemental fat post-partum, on subsequent production and reproductive efficiency of dairy cows. Forty-eight multiparous Holstein-Friesian dairy cows were assigned to one of two groups, six weeks prior to expected calving date and fed a grass based total mixed ration according to ME requirements for late gestation. Group 1 was supplemented with barley (B) or molassed sugar beet feed (SB) prior to calving and was then given a high starch lactation ration. Group 2 was supplemented with either fat (F) or no supplement (C) pre partum, and was then given a similar lactation ration as Group 1 but supplemented with fat. Lactation rations were fed through to week-20 post partum and the cows were monitored during this period. Milk yield (P<0.002) and milkfat (P<0.02) production were higher and milk protein concentration (P<0.001) was lower in Group 2. The number of days to first rise in progesterone following parturition was greater (P<0.01) in Group 2. Due to the design of the study, effects of prepartum supplementation were only evaluated within each lactation ration group. Conception rate to first service was higher (P<0.001) for B than SB supplemented cows in Group 1 and higher (P<0.02) for F than C supplemented cows in Group 2. Services per conception were lower (P=0.06) for B than SB supplemented cows in Group 1 and lower (P<0.05) for F than C supplemented cows in Group 2. Overall pregnancy rates and days open were not significantly different between the groups. The data shows that pre-partum nutrition had an important role in determining subsequent fertility. Despite having negative effects early post partum, supplementing with fat did not affect overall reproductive performance but it did improve milk production.

Timing of melatonin treatment: differential effects on oestrus and coat growth in goats

1997 ◽  
Vol 65 (2) ◽  
pp. 267-273 ◽  
Author(s):  
I. A. Forsyth ◽  
F. E. Gebbie ◽  
J. Arendt
Keyword(s):  
Goat Milk ◽  
Normal Weight ◽  
Ovarian Activity ◽  
Plasma Prolactin ◽  
Dairy Goats ◽  
Group 4 ◽  
Group 3 ◽  
Group 5 ◽  
Group 2 ◽  
Group 1

AbstractTo avoid winter scarcity of fresh goat milk, simple methods of advancing the season of kidding would be commercially valuable. A combination of long-day light treatment followed by melatonin is successful but other aspects of seasonality including coat growth are also reset. To investigate whether effects on breeding season and coat growth can be dissociated, British Saanen dairy goats (no. = 30) were randomly allocated to one of six groups. Control goats were untreated. Goats in the other five groups received 2 months of treatment with 20 h light: 4 h darkness (20L: 4D) and were then given 3 mg melatonin orally at 16.00 hfor 2 months. The treatments started on 11 January (group 1), 29 March (group 2), 14 June (group 3), 30 August (group 4) and 8 November (group 5). Weekly blood samples were taken for the measurement of progesterone to monitor ovarian activity and prolactin. Side patches (10 cm ×10 cm) were clipped monthly from alternate sides and weighed to measure coat growth. The onset of ovarian activity was advanced from a median date of 15 November in controls to 24 May in group 1 (P < 0·01), 16 August in group 2 (P < 0·05) and 18 October in group 3 (? < 0·05). Groups 4 and 5 showed no significant change in the onset of oestrus (median onset dates 8 November and 1 November, respectively). Group 1 goats came into season again with controls in November. In all except group 5, treatment interacted with time to affect significantly the growth of the coat. The pattern of coat growth was most altered (P < 0·001) in groups 1 and 2. This was associated with effects on plasma prolactin concentrations of light stimulation and melatonin suppression. Group 1 goats resynchronized with control goats to show a coat of normal weight in the winter following treatment. Division of milking goat herds into spring and autumn kidding groups is, therefore, a practical possibility, but effects on overall milk yield require study.

scholarly journals INJECTABLE COPPER AND ZINC FOR GRAZING YEARLING STEERS

1987 ◽  
Vol 67 (4) ◽  
pp. 1033-1041
Author(s):  
F. A-R. SANKOH ◽  
R. J. BOILA
Keyword(s):  
Body Weight ◽  
Dry Matter ◽  
Phase 1 ◽  
Sole Source ◽  
The Body ◽  
Mineral Supplements ◽  
Copper Zinc ◽  
Group 2 ◽  
Cu And Zn ◽  
Group 1

Injectable Cu and Zn were evaluated as mineral supplements using 37 purebred Herefords (Group 1) and 23 Angus-Charolais-North Devon crosses (Group 2). The 60 steers were carried through a 113-d grazing phase. This was followed by a 79-d finishing phase for all steers of Group 1 and seven steers of Group 2. Treatments were combinations of the non-dosing (0Cu, 0Zn) and dosing (+Cu, +Zn) of steers with injectable Cu or Zn at the start of the grazing phase: (1) 0Cu, 0Zn; (2) +Cu, 0Zn; (3) 0Cu, +Zn; and (4) +Cu, +Zn. Injectables were the sole source of supplementary Cu and Zn during grazing and finishing phases. Means (SE) for Cu and Zn, respectively, in forages as milligrams per kilogram dry matter (DM) during the grazing phase were: grasses, 4.4 (0.17), 15.7 (0.46); alfalfa, 6.9 (0.18), 16.5 (1.49); and birdsfoot trefoil 5.0 (0.76), 15.0 (3.41). Injectable Cu did not influence (P > 0.05) body weight during the grazing phase. Body weight responses were lower (P < 0.05) for +Cu steers in the finishing phase, when dietary Cu was low, but steers could not be classified as Cu-deficient based on liver Cu. Liver Cu increased to means greater than 140 mg kg−1 DM in all steers, but was higher (P < 0.05) in +Cu steers during the grazing phase. Serum Cu varied widely during the grazing phase, but was higher (P < 0.05) for +Cu steers only on day 84 of the grazing phase. Neither liver Cu nor serum Cu was influenced (P > 0.05) by injectable Zn. Injectable Zn decreased growth rates in the latter part of the grazing phase but did not affect (P > 0.05) the body weight response during the finishing phase. The concentrations of Zn in liver and serum were not influenced (P > 0.05) by injectable Cu or Zn. Key words: Cattle, grazing, copper, zinc, injectable copper, injectable zinc

scholarly journals Randomised clinical trial showing the curative effect of bandaging on M2-stage lesions of digital dermatitis in dairy cows

2019 ◽  
Vol 6 (1) ◽  
pp. e000264 ◽  
Author(s):  
Marcus Klawitter ◽  
Dörte Döpfer ◽  
Theo Broderick Braden ◽  
Ermias Amene ◽  
Kerstin Elisabeth Mueller
Keyword(s):  
Clinical Trial ◽  
Dairy Cows ◽  
Dairy Herd ◽  
Randomised Clinical Trial ◽  
Digital Dermatitis ◽  
Group 4 ◽  
Treatment Type ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Objectives and designThis trial evaluated the effect of bandaging of acute painful ulcerative bovine digital dermatitis (DD) lesion (stage M2) in dairy cows, tested using two different topical treatments.DesignRandomised clinical trial.SettingThis study was conducted using Holstein-Friesian cows ranging in age from heifers to fourth lactation in a single dairy herd and diagnosed with acute ulcerative DD lesions (stage M2) on the first examination (week 0). Cows were randomly assigned into either a non-bandaged or bandaged group across two treatment conditions: topical chlortetracycline spray (CTC) and Intra Hoof-Fit Gel (IHF). Lesions received standardised bandaging and treatment on a weekly basis. Unhealed lesions could receive up to five repeated treatments, at weekly intervals, within a four-week period. Both M-stage and locomotion were also evaluated and scored weekly. Cows with healthily formed skin (stage M0) were deemed healed and subsequently released from the study.ResultsIn total, 163 M2 lesions were diagnosed at week 0. Bandaged M2 lesions had a significantly higher probability of cure than non-bandaged lesions regardless of treatment type (HR: 4.1; P<0.001; 95 per cent CI: 2.5 to 6.8). Most healing occurred within the first three weeks of trial. Furthermore, bandaged lesions (group 2 and group 4) were significantly less likely to progress into the chronic hyperkeratotic or proliferative stage (M4) than non-bandaged lesions in group 1 and group 3 (HR: 0.10; P<0.001; 95 per cent CI: 0.04 to 0.22). Out of concern for the cow’s wellbeing, this study investigated the effects of bandaging on locomotion. Bandaging had no effect on locomotion for either cows treated with CTC (group 1: median Sprecher score, 2; IQR=1–2; group 2: median Sprecher score, 2; IQR=1–3; P=0.3) or IHF (group 3: median Sprecher score, 2; IQR=1–2; group 4: median Sprecher score, 2; IQR=1–3; P=0.3).

scholarly journals Effect of the first and second postpartum partial milking on blood serum calcium concentration in dairy cows

2014 ◽  
Vol 59 (No. 3) ◽  
pp. 128-133
Author(s):  
E.G. Salgado-Hernández ◽  
A. Aparicio-Cecilio ◽  
F.H. Velásquez-Forero ◽  
D.A. Castillo-Mata
Keyword(s):  
Blood Serum ◽  
Dairy Cows ◽  
Serum Calcium ◽  
Metabolic Disorders ◽  
Calcium Concentration ◽  
Atomic Absorption Spectrophotometry ◽  
Serum Calcium Concentration ◽  
Group 2 ◽  
Group 1

Parturient paresis and subclinical hypocalcemia are frequent metabolic disorders in dairy cows postpartum. The aim of this study was to determine the effect of postpartum partial milking in the first two milkings on blood serum calcium concentration in dairy cows. Twenty multiparous Holstein dairy cows were randomized into two groups. Cows of group 1 (n = 10) were partially milked at the first and second milking postpartum. Cows of group 2 (n = 10) were completely milked. Blood samples were collected from all animals 5&ndash;7 days before calving, within 30 min after calving, and 4, 8, 12, 16, 20, 24, 28, and 32 h after calving for determination of serum calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations. Colostrum production was registered and sampled in the first and second milking. Concentration of Ca in colostrum was determined by atomic absorption spectrophotometry. Serum Ca and P concentrations decreased in both groups after parturition (P &lt; 0.05) and remained low during 32 h postpartum with no difference observed between groups (P &gt; 0.05). Serum concentrations of Mg were stable in all samples and no statistical difference was observed between groups (P &gt; 0.05). Colostrum production was higher in completely milked cows only in the first postpartum milking (P &lt; 0.05), but there was no difference between groups at the second milking. Total Ca secretion in colostrum was higher in the complete milking group at the first and second postpartum milking. Colostrum Ca secretion increased at the second milking with respect to the first one in both groups (P &lt; 0.05). There was no correlation between serum Ca and colostrum Ca (P &gt; 0.05). In this study, the partial milking of colostrum in the first and second milking postpartum did not prevent subclinical hypocalcemia in dairy cows. &nbsp;

Milk yield at first lactation, parity, and season of calving affect the reproductive performance of water buffalo cows

2020 ◽  
Vol 60 (8) ◽  
pp. 1073
Author(s):  
Héctor Nava-Trujillo ◽  
Robert Valeris-Chacin ◽  
Armando Quintero-Moreno ◽  
Juan Escalona-Muñoz
Keyword(s):  
Milk Yield ◽  
Reproductive Performance ◽  
Water Buffalo ◽  
Negative Energy ◽  
Calving Interval ◽  
Water Buffaloes ◽  
Group 4 ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Context Profitability of water buffalo systems depends on a calving interval (CI) &lt;400 days. Several factors affect the achievement of this target. However, milk yield at first lactation has received little attention. Aims Determine the effect of milk yield at first lactation, parity, season of calving and farm, on the length of CI and the probability of a CI ≤ 400 days in water buffaloes. Methods A retrospective analysis of milk yield at first lactation and reproductive records of 1459 water buffaloes was carried out. Milk yield was categorised as Group 1 (≤1090 kg), Group 2 (1090–1377 kg), Group 3 (1377–1684 kg) and Group 4 (&gt;1684 kg); parity was categorised as parity 1, 2 and ≥ 3; and month of calving was grouped into three seasons: December–March, April–July, and August–November. Data were analysed using linear and logistic mixed models. Key results CI increased from 425.3 days (95% CI: 418.8–431.8 days) in group 1 to 463.3 days (95% CI: 456–470.6 days) in group 4 (P &lt; 0.05), while the probability of having a CI ≤ 400 days decreased from 0.5 (95% CI: 0.46–0.54) to 0.26 (95% CI: 0.22–0.29), respectively (P &lt; 0.05). CI decreased from 466 days (95% CI: 460.8–471.3 days) in parity 1 to 410.5 days (95% CI: 405.2–415.8 days) in parity ≥3, whereas the probability of a CI ≤ 400 days increased from 0.26 (95% CI: 0.24–0.29) to 0.51 (95% CI: 0.47–0.54) respectively (P &lt; 0.05). Water buffaloes calving in August–November showed significantly shorter CI and, along with those calving between December–March, showed the highest probability of a CI ≤ 400 days. An interaction between milk yield at first lactation and parity on both outcomes was observed. Conclusions Shorter CI and higher probability of a CI &lt;400 days were associated with lower milk yields at first lactation, higher parity and calving between August–November. Higher milk yield at first lactation affected negatively the reproductive performance of water buffaloes, especially at parity 1 and 2. Implications These results highlight the importance of adequate nutritional management to allow water buffaloes to cope with the challenge of the postpartum negative energy balance and have a calving interval less than 400 days.

scholarly journals OMASAL MORPHOLOGY OF DAIRY COWS FED WITH HIGH OR LOW GRAIN CONTENT DIET PRIOR PARTURITION

2015 ◽  
Vol 39 (6) ◽  
pp. 583-592
Author(s):  
Danilo de Oliveira Rocha Bhering Santoro ◽  
João Chrysostomo Resende Júnior ◽  
Ronaldo Francisco de Lima ◽  
João Luiz Pratti Daniel ◽  
Matheus Balduíno Moreira ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Mitotic Index ◽  
Nutrient Intake ◽  
Dry Matter ◽  
Post Partum ◽  
High Energy ◽  
Holstein Cows ◽  
Morphological Response

ABSTRACT Little is known about the morphological response of the omasum in dairy cows that consume a high-energy diet pre-partum. The aim of this study was to investigate whether a transitional diet with high grain content is able to induce changes in omasum morphology. Six weeks before the expected calving, four Holstein cows were fed a standardization diet, and four weeks before delivery, the cows were fed a diet with high grain content (HGC) or low (LGC) grain content. After calving, all of the cows were fed a high energy lactation diet. The cows that were fed the HGC diet pre-partum had higher dry matter and nutrient intake than the cows that were fed the LGC diet. The mitotic index of the omasum epithelium was higher than the mitotic index in the rumen, but apparently the response to the diet stimuli was slower. In the cows that were fed the HGC diet, the omasum papillae were taller one week before parturition and two weeks post-partum. Cows that were fed the HGC diet had a thinner epithelium due to thinner non-keratinized layers of the omasum epithelium. We conclude that the omasum mucosa of dairy cows responds to the stimuli of a pre-partum HGC diet, which was indicated by the greater height of the omasum papillae and by the reduced thickness of the omasum epithelium. It seems that the mitotic index responds a little more slowly, but the response to the diet stimuli is stronger in the omasum epithelium than in the rumen.

scholarly journals Two Possibile Hormonal Treatment Methods for Inducing Follicular Growth in Dairy Cows With Inactive-Static Ovaries

2014 ◽  
Vol 37 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Branko Atanasov ◽  
Ljupco Mickov ◽  
Igor Esmerov ◽  
Ksenija Ilievska ◽  
Martin Nikolovski ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dairy Cows ◽  
Hormonal Treatment ◽  
Ovarian Response ◽  
Control Group ◽  
Follicular Growth ◽  
Cyclic Activity ◽  
Treatment Methods ◽  
Group 2 ◽  
Group 1

AbstractPostpartum anestrus is a physiological phenomenon in high-producing dairy cows. Static ovaries have been related as major contributors for its occurrence causing a significant reproductive problem to the dairy industry. Different treatment methods have been employed with inconsistent rate of success in initiation of cyclicity, requiring further investigations in order to achieve satisfactory results. The aim of the present study was to compare the ovarian response in cows diagnosed with static ovaries, more than 60 days postpartum using two different hormonal treatment (GnRH and eCG) methods. A total of 58 acyclic cows (no CL, follicles<8mm, P4<0.5ng/mL) were randomly divided into three groups: GnRH (Group 1, n=23), eCG (Group 2, n=23) and Controls (n=12), and allocated thereafter, into subgroups according to the applied doses of GnRH (100μg or 250μg); eCG (750 IU or 1000 IU) whilst control group cows were left untreated. Daily follicular growth rate and treatment respond interval were estimated based on repeated ultrasound examinations. Blood serum P4 sampling was done on d -7, d-0 (start of the experiment) and on d 7 after ovulation. Resumption of cyclic activity occurred in 55.17% (32/58) of the treated cows, 56.52% in Group 1; 60.86% in Group 2 and 41.66% in the control group. Overall, the follicular growth rate was similar between the trials group and significant with regard to the cows in the control group (p<0.05). eCG or GnRH treated cows responded significantly faster 6.85±0.2 and 7.84±0.2 days, respectively, in comparison to the control group cows (17±0.7 days, p<0.001). Treatment with a single dose of GnRH or eCG caused resumption of follicular growth and ovulation following luteogenesis (forming CL) without significant changes in P4 concentrations on day 7 after ovulation (p>0.05). Cows in Group 2 had significantly higher incidence of multiple ovulations than cows in Group 1 (p<0.05). The eCG treatment resulted in a faster response and higher ovulation rate compared to GnRH treatment. In conclusion, both treatments have shown acceptable results in resumption of cyclicity in dairy cows with static ovaries.

Abnormal patterns of ovarian activity in dairy cows and their relationships with reproductive performance

1980 ◽  
Vol 30 (2) ◽  
pp. 177-188 ◽  
Author(s):  
D. Claire Bulman ◽  
P. D. P. Wood
Keyword(s):  
Luteinizing Hormone ◽  
Dairy Cows ◽  
Reproductive Performance ◽  
Profile Analysis ◽  
Single Injection ◽  
Ovarian Activity ◽  
Luteinizing Hormone Releasing Hormone ◽  
Treatment Groups ◽  
Intravaginal Device ◽  
Ovarian Cycles

ABSTRACTProgesterone profiles were obtained from 533 dairy cows during the interval from calving to the re-establishment of pregnancy by twiceweekly radioimmunoassay of milk progesterone. The importance of abnormal patterns of ovarian activity on herd fertility was determined. Animals were divided into five categories based on profile analysis: A, normal; B, delayed start to ovarian cycles; C, cessation of cycles; D, prolonged luteal activity; and E, silent oestrus. Animals in categories B to E were subdivided into treatment groups: categories B and C either (i) untreated controls, (ii) single injection 0·5 mg luteinizing hormone-releasing hormone (Hoechst) or (iii) progesterone-releasing intravaginal device (Abbott Laboratories Ltd) inserted for 14 days; categories D and E either (i) untreated controls or (ii) single injection 0-5 mg cloprostenol (Imperial Chemical Industries).The proportion of cows in each category was: A 77·5%; B 4·9%; C 5·1%; D 1·9%; and E 10·7%. The incidence of ‘normal’ cows was 75% (first lactation), 80% (2nd to 5th lactations) and 69% (5th to 11th lactations). For normal cows (no. = 413) the interval to the start of cyclicity varied significantly with season but was not correlated with either the intervals to first insemination or to conception. In categories B to E the open period, the number of services per conception, and the days from first insemination to conception were greater than in category A, but only in category C were any differences significant. None of the treatments reduced calving-toconception intervals.

scholarly journals Effects of Polyunsaturated Fatty Acids (PUFA) Supplementation on Reproductive Performance of Beef Heifers Submitted to Fixed-time Artificial Insemination (FTAI) Protocol

2019 ◽  
Vol 47 (1) ◽  
Author(s):  
João Batista Souza Gorges ◽  
Andressa Varella Gonsioroski ◽  
Eduardo Pradebon Da Silva
Keyword(s):  
Reproductive Performance ◽  
Reproductive Function ◽  
Pregnancy Rates ◽  
Beef Heifers ◽  
Pufa Supplementation ◽  
Group 2 ◽  
Ovulatory Follicles ◽  
Dietary Treatments ◽  
And Control ◽  
Group 1

Background: More recently, polyunsaturated fatty acids (PUFA) supplements have been used in grazing beef herds in attempt to influence specific metabolic pathways and hormones that directly modulate reproductive function. Supplementation of calcium salts of PUFA can positively influence ovarian follicular growth, luteal function, and improve reproductive performance in dairy and beef females. The aim of this experiment was to evaluate strategies of dietary treatments using PUFA supplementation for 30 days before or after FTAI protocol and its effects on of ovulatory follicle size, ovulation, pregnancy and gestational losses rates in beef heifers.Materials, Methods & Results: One hundred and ninety-nine Brangus heifers (24 ± 3 months-old; BW= 320 ± 15 kg; BCS= 2.85 ± 0.17) were randomly assigned in three different groups to receive dietary treatments. Group 1 (n = 70) was fed with 0.5 kg/day of a protein-mineral mixture supplement containing 0.2 kg/day PUFA (Mix A)during 30 days before FTAI, Group 2 (n = 68) received the same supplement 30 days after FTAI and Control (n = 61) only the supplement without PUFA (Mix B) during all period. Heifers were submitted to estrous synchronization treatment using progesterone (P4), estradiol benzoate (E2) and prostaglandin F2a  (PGF). Ultrasound exams were done to measure ovulatory follicle diameter and to determinate ovulation and pregnancy rates on Day 30 and 60 after FTAI. Daily gain (DG) was higher (P < 0.05) only when heifers received supplement containing PUFA (Group 1= 30 days prior FTAI) and (Group 2= 30 days after FTAI). PUFA supplementation before FTAI also resulted in larger ovulatory follicles diameter (P < 0.05) in Group 1 (11.2 ± 2.5 mm) compared to Group 2 (9.9 ± 2.3 mm) and Control (10.0 ± 2.07 mm). Ovulation rates were similar (P > 0.05) in Group 1 (90%), Group 2 (75%) and Control (67%). Pregnancy rates were higher (P < 0.05) in Group 1 (Day 30= 67.1% and Day 60= 64.2%) when compared with Group 2 (Day 30= 48.5% and Day 60= 44.1%) and Control (Day 30= 49.2% and Day 60= 45.9%). Gestation losses were similar (P > 0.05) among Groups 1 (6.6%), 2 (9%) and Control (6.6%).Discussion: Rumen-protected supplemental lipids have been used to increase energy density and to determine direct positive effects on reproduction in dairy and beef herds.  There is evidence that feeding moderate amounts of PUFA supplements can improve energy status and result in significant differences in DG as it was observed during experimental period. Thus, heifers that received 0.2 kg/day of PUFA supplement 30 days before FTAI protocol had also a positive effect on ovulatory follicles size, but ovulation rates were similar in groups. Beneficial effects of pre-breeding PUFA supplementation were observed on pregnancy rates on Days 30 and 60 after FTAI, but pregnancy loss was not different among dietary treatments in beef heifers. Based on this study, PUFA supplementation before FTAI protocol had a positive effect on reproductive performance of beef heifers by directly improving ovarian function, uterine environment and early embryonic development. Results indicate that pre-breeding PUFA supplementation to beef heifers is a suitable strategy to increase pregnancy rate in FTAI programs. Therefore, for a better understanding of interactions of nutritional strategies and utero-ovarian functions more evaluations are needed to understand the mechanisms by which feeding PUFA may improve reproductive function in beef heifers.

Sign in / Sign up

Export Citation Format

Share Document