Calving probability in the first and second reproductive years of beef heifers that reached the recommended body weight at first breeding season

Calving records of 174 2-yr-old heifers from four breed groups; Hereford (HE), Beef Synthetic (SY), Dairy Synthetic (SD) and Crossbred Hereford (HX) were used in this study. Half of the heifers were exposed to three epididymectomized bulls for 6 wk before the start of the breeding season. While exposure to bulls had little influence (P = 0.51) on pregnancy rate, it advanced the calving date by 5.5 days compared with the control group (P < 0.05). Calving season in the exposed heifers was 2 wk shorter than that in the control group. Effect of heifer body weight at the start of breeding season on pregnancy rate differed (P < 0.05) among the four breed groups. Low body weight at mating was associated with lowered fertility in SY, SD and HE while very heavy body weight resulted in lowered fertility in SY and SD breed groups. Increase in body weight advanced calving date in the HX breed group only. Key words: Beef cattle, heifer reproduction, bull exposure, body weight

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Difference in Body Weight at Breeding Affects Reproductive Performance in Replacement Beef Heifers and Carries Consequences to Next Generation Heifers

Animals ◽

10.3390/ani11102800 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2800

Author(s):

Ramanathan K. Kasimanickam ◽

Vanmathy R. Kasimanickam ◽

Madison L. McCann

Keyword(s):

Body Weight ◽

Breeding Season ◽

Reproductive Performance ◽

Production Traits ◽

Next Generation ◽

Beef Heifers ◽

Balanced Diet ◽

Reproductive Indices

Nutrition imprinting carries consequences across generations. The effect of 55% vs. 65% of mature cow body weight (MBW; 545 kg) at breeding on the reproductive performance of heifers and their offspring was investigated. Angus-cross dam heifers were randomly fed to attain 55% (n = 1622) vs. 65% (n = 1578) of MBW, and offspring (F1) heifers born to dam heifers [55% (n = 1285) vs. 65% (n = 1324)] were fed to attain 65% of MBW. Bodyweight and reproductive indices were recorded throughout the study. In dam heifers, puberty (44% vs. 53%), breeding season pregnancy (86.4% vs. 90.6%) and 21-day calving rates (55.2% vs. 65.4%) did vary, but dystocia rate (8.7% vs. 9.0%) did not differ between 55% and 65% MBW groups. Puberty (49.2% vs. 58.2%), breeding season pregnancy (87.2% vs. 92.8%) and 21-day calving rates (53.8% vs. 64.1%) did differ (p < 0.05), but dystocia rate (8.4 vs. 9.2%) did not differ between F1 heifer groups. In conclusion, 55% of MBW at breeding negatively affected the reproductive performance of heifers and its offspring heifers. The recommendation is to feed heifers a balanced diet to reach 65% of MBW at breeding with consideration of production traits.

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PSV-18 The role of leptin in feed efficiency and behavior attributes of commercial beef heifers

Journal of Animal Science ◽

10.1093/jas/skaa054.286 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 162-162

Author(s):

Nayan Bhowmik ◽

Kris A Ringwall ◽

Carl R Dahlen ◽

Kendall C Swanson ◽

Jeffrey A Clapper ◽

...

Keyword(s):

Feeding Behavior ◽

Breeding Season ◽

Feed Intake ◽

Feed Efficiency ◽

Repeated Measures ◽

Fixed Effects ◽

Beef Heifers ◽

Frame Size ◽

And Behavior ◽

Plasma Leptin

Abstract Leptin is a 16-kDa-peptide hormone product of the leptin gene (LEP) that is predominantly synthesized by adipose tissues and has known involvement in regulation of feed intake, energy expenditure, reproduction, and immune functions. The objective was to determine the association of leptin genotype (LEP c.73C >T), leptin diplotype (LEPD) and plasma leptin hormone (LEPH) concentration with growth, feed intake, feed efficiency, and behavior characteristics in developing beef heifers. A total of 336 commercial beef heifers were genotyped for the LEP c.73C >T marker. Four single nucleotide polymorphism markers including LEP c.73C >T, ARS-BFGL-NGS-59298 (intron 1), BovineHD0400026029 (upstream) and BovineHD0400026063 (downstream) of LEP were considered for haplotype analysis. Eleven LEPD were identified for this study using parsimony-based analyses. Circulating levels of LEPH were measured on 333 heifers prior to their first breeding season and used to assign low or high concentration group based on population median. Data were analyzed using the mixed procedure of SAS for repeated measures, fixed effects of ancestral breed group (n = 4), dam age category (n = 4), frame size group (n = 4), project cycle nested within birth year (n = 6), week of feed trial × year, LEP (n = 3) or LEPD (n = 11) or LEPH (n = 2), as well as week × LEPH (only for LEPH). There were no significant differences between LEP genotypes (P ≥ 0.11) or LEPD (P ≥ 0.33) for any of the studied traits. Heifers with low LEPH ate fewer meals per day (P = 0.02) and had more DMI per meal (P = 0.04) compared to those with high plasma leptin. Further research is needed to better understand plasma LEPH concentration and its role in feeding behavior attributes. However, circulatory LEPH before the breeding season may serve as a predictor for feeding behavior.

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Beef heifer fertility: importance of management practices and technological advancements

Journal of Animal Science and Biotechnology ◽

10.1186/s40104-020-00503-9 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Sarah E. Moorey ◽

Fernando H. Biase

Keyword(s):

Breeding Season ◽

Production Systems ◽

Transcript Abundance ◽

Antral Follicle ◽

Economic Losses ◽

Beef Heifers ◽

Management Procedures ◽

Beef Heifer ◽

Fertility Potential ◽

Cow Calf

Abstract The development of replacement heifers is at the core of cow-calf beef production systems. In 2020, the USDA, National Agricultural Statistics Service reported 5.771 million beef heifers, 500 pounds and over, are under development for cow replacement. A compilation of data from several studies indicate that between 85% and 95% of these heifers will become pregnant in their first breeding season. Several thousands of heifers being raised for replacement may not deliver a calf on their first breeding season and result in economic losses to cow-calf producers. Many management procedures have been developed to maximize the reproductive potential of beef heifers. Such approaches include, but are not limited to the following: nutritional management for controlled weight gain, identification of reproductive maturity by physiological and morphological indicators, and the implementation of an estrous synchronization program. The implementation of management strategies has important positive impact(s) on the reproductive efficiency of heifers. There are limitations, however, because some heifers deemed ready to enter their first breeding season do not become pregnant. In parallel, genetic selection for fertility-related traits in beef heifers have not promoted major genetic gains on this particular area, most likely due to low heritability of female fertility traits in cattle. Technologies such as antral follicle counting, DNA genotyping and RNA profiling are being investigated as a means to aid in the identification of heifers of low fertility potential. To date, many polymorphisms have been associated with heifer fertility, but no DNA markers have been identified across herds. Antral follicle count is an indication of the ovarian reserve and is an indicator of the reproductive health of a heifer. We have been working on the identification of transcriptome profiles in heifers associated with pregnancy outcome. Our current investigations integrating protein-coding transcript abundance and artificial intelligence have identified the potential for bloodborne transcript abundance to be used as indicators of fertility potential in beef heifers. In summary, there is an ongoing pressure for reducing costs and increasing efficiency in cow-calf production systems, and new technologies can help reduce the long-standing limitations in beef heifer fertility.

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8 Evaluation of puberty induction protocol in peripubertal beef heifers prior to fixed-time AI programs

Reproduction Fertility and Development ◽

10.1071/rdv31n1ab8 ◽

2019 ◽

Vol 31 (1) ◽

pp. 129

Author(s):

J. B. S. Borges ◽

D. S. V. Luiz ◽

P. R. L. Aguiar ◽

C. G. B. Berlitz ◽

G. S. Velho ◽

...

Keyword(s):

Breeding Season ◽

Body Condition ◽

Body Condition Score ◽

Animal Health ◽

Hormonal Treatment ◽

Fixed Time ◽

P Value ◽

Ovarian Activity ◽

Beef Heifers ◽

Condition Score

Beef heifers that conceive early during their first breeding season calve earlier, wean heavier calves, and tend to continue doing so throughout the rest of their reproductive lives. Otherwise, under extensively managed systems in Southern Brazil, only a variable proportion of 2-year-old beef heifers reach puberty before the start of the breeding season. The aim of this study was to evaluate a protocol to induce puberty in peripubertal beef heifers using injectable progesterone (P4) and oestradiol cypionate (EC) to improve pregnancy per AI (P/AI) in fixed-time AI (FTAI) programs. A total of 311 Angus heifers, 24±3 months of age, 3.1±0.3 body condition score (1=emaciated; 5=obese), and 328±41kg of body weight (BW), were examined before FTAI protocol (Day −24) by transrectal ultrasonography to determine reproductive tract score (RTS; 1=prepubertal; 5=pubertal). Prepubertal heifers (RTS 1; 12.8%, 40/311) were excluded from the study. Heifers with RTS=2 (n=271) were assigned to 2 groups: P4 (RTS 2 or 3, n=100) and cyclic (RTS 4 and 5, n=171). Peripubertal heifers were treated on Day −24 with 150mg of injectable P4 IM (Sincrogest® injectable, Ourofino Animal Health, Cravinhos, Brazil) and on Day −12 received 1mg of EC IM (Sincro CP®, Ourofino Animal Health). Cyclic heifers received no hormonal treatment before FTAI protocol. On Day 0, heifers in the P4 group were evaluated again to determine RTS, body condition score, and BW. Induction of puberty was defined by the presence of a follicle >8.5mm (RTS=4) or a corpus luteum (RTS=5). All heifers received an FTAI protocol consisting of 2mg of oestradiol benzoate IM (Sincrodiol®, Ourofino Animal Health) and an intravaginal progesterone implant (1 g; Sincrogest®, Ourofino Animal Health). On Day 8, heifers had implants removed and were injected with 1mg of EC and 500µg of sodium cloprostenol IM (Sincrocio®, Ourofino Animal Health). After 48h, all heifers received an FTAI. Thirty days after AI, the diagnosis of gestation was performed by ultrasonography. Statistics included chi-square and linear regression with coefficients analysed as independent variables, considering a significant P-value of 0.05. On Day 0, percentages of RTS 5, 4, and 3 in the P4 heifers were 37, 27, and 36%, respectively, resulting in 64% of puberty induction. The P/AI was similar (P=0.14) in P4-treated and cyclic heifers (59v. 50.3%, respectively). The regression analysis presented a linear and positive effect of BW on P/AI (P<0.001) in cyclic heifers and a positive influence of BW on RTS (P=0.05) and RTS on P/AI (P=0.008) in P4-treated heifers. The application of RTS system associated with P4 treatment of peripubertal heifers before FTAI protocol improved ovarian activity and might have contributed to higher P/AI, comparable with that achieved in cyclic heifers.

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50 Effects of post-weaning supplementation of immunomodulatory feed ingredient on body weight and cortisol levels in programmed fed beef heifers

Journal of Animal Science ◽

10.1093/jas/skz053.187 ◽

2019 ◽

Vol 97 (Supplement_1) ◽

pp. 82-82

Author(s):

Jessica L Danielo ◽

Jessie Tipton ◽

Ralph Ricks ◽

Keelee J McCarty ◽

Nathan Long

Keyword(s):

Body Weight ◽

Repeated Measures ◽

Serum Cortisol ◽

Corn Germ ◽

Experimental Unit ◽

Beef Heifers ◽

Feed Ingredient ◽

Repeated Measures Analysis ◽

Post Infusion ◽

Cortisol Levels

Abstract The objective of this study was to determine the effects of an immunomodulatory feed ingredient during post-weaning on growth and cortisol levels of beef heifers. Commercial Angus heifers (n = 72) from two AI sires were blocked (n = 9) by sire and BW and then randomly assigned to one of two pens per block. Each pen (4 heifers/pen) per block was assigned to one of the treatments. Heifers were fed a commercial TMR twice daily from d 0 to 60 to gain 0.75 kg/day. The feed was top-dressed once a day with either 72g of Celmanax (CEL) or 72g of corn germ (CON) per pen. Body weight was collected on d -1, 0, 15, 30, 45, 60 and 61. Blood samples were collected on d 0, 15, 30, 45 and 60. Sixteen heifers (n = 8 CEL; n = 8 CON) were randomly selected for a corticotropin releasing hormone/ arginine vasopressin (CRH/AVP) challenge after the 60 d period. Two heifers per pen (n = 32) were randomly selected for a transportation challenge to evaluate stress response on d 61 or 62 of the study. Pen was the experimental unit and data was analyzed by ANOVA or repeated measures analysis as appropriate. Feed efficiency and BW gain was increased (P = 0.04) in CEL heifers compared to CON heifers. Serum cortisol concentrations were decreased (P < 0.01) in CEL heifers compared to CON heifers on d 30 to 60 post-weaning. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers during the CRH/AVP challenge from 60 to 150 minutes post infusion. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers throughout the transportation challenge. In summary, supplementation of Celmanax post-weaning increased BW gain and reduced cortisol concentrations in beef heifers.

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Can fruit pulp meet the calcium needs of tropical frugivorous passerines during reproduction?

Journal of Tropical Ecology ◽

10.1017/s0266467413000643 ◽

2013 ◽

Vol 30 (1) ◽

pp. 79-88 ◽

Cited By ~ 2

Author(s):

Mercedes S. Foster

Keyword(s):

Body Weight ◽

Breeding Season ◽

Dry Weight ◽

Floodplain Forest ◽

Fruit Pulp ◽

Natural Mineral ◽

South Eastern ◽

Mineral Licks ◽

Calcium Sources ◽

The Way

Abstract:Calcium is an important nutrient for birds, especially for eggshell production and the mineralization of the skeleton of developing young. In temperate regions insects and seeds that form the bulk of the diet of breeding passerines do not contain sufficient calcium to meet the needs of breeding females and young; these birds obtain their calcium by eating snails, woodlice and millipedes. Little is known about the way tropical frugivorous passerines meet their calcium needs. The calcium contents of fruits of 34 species eaten by birds during the breeding season in mature floodplain forest in south-eastern Peru were determined. The suitability of these fruits as calcium sources for hypothetical 10-g and 25-g birds and for 26 species of frugivore that breed at the study site was evaluated based on bird body weight and on the rictal width of the bill, which influences feeding. Fruits of five species in the study area appear to be suitable sources of calcium for birds ≤25 g, although those of Ficus killipii (Moraceae) are likely optimal. The latter contain a lot of calcium (2.48% dry weight of pulp or c. 4.15 mg per pulp per fruit) and are small enough (mean diam. = 9 mm) for most birds to swallow whole, and trees produce large crops. Snails, woodlice and millipedes are common in the area and also contain sufficient calcium to meet birds’ needs. In addition, birds could likely meet their calcium needs through geophagy at natural mineral licks.

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Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs

Animal Science ◽

10.1017/s0003356100023217 ◽

1979 ◽

Vol 28 (3) ◽

pp. 297-307 ◽

Cited By ~ 16

Author(s):

J. F. Quirke

Keyword(s):

Body Weight ◽

Breeding Season ◽

Litter Size ◽

Conception Rate ◽

Restricted Feeding ◽

Ewe Lambs ◽

Younger Age ◽

Body Weights ◽

The Mean ◽

Ad Libitum

ABSTRACTGroups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.

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Supplementation of grazing heifers with different protein sources

Revista Mvz Córdoba ◽

10.21897/rmvz.2027 ◽

2021 ◽

Vol 26 (2) ◽

pp. e2027

Author(s):

Román Enrique Maza-Ortega ◽

Deilen Paff Sotelo-Moreno ◽

Mauricio Miguel-Estrada ◽

Libardo Alfonso Maza-Angulo ◽

Mário Fonseca-Paulino

Keyword(s):

Body Weight ◽

Wheat Bran ◽

Soybean Meal ◽

Metabolic Profile ◽

Daily Weight Gain ◽

Beef Heifers ◽

Final Body Weight ◽

Blood Concentrations ◽

Protein Sources ◽

Average Body

Objective. Evaluate the effects of supplementation with different protein sources (soybean meal and wheat bran with urea) on the productive performance, intake, digestibility, microbial protein synthesis, and metabolic profile of grazing beef heifers. Materials and methods. Were used twenty Nellore heifers at 8.5±0.06 months of age, with an initial average body weight of 241.5±4.71 kg. The animals were distributed in a completely randomized deseing with two treatments and ten replicates. Two protein sources in the supplements were evaluated: 1) Soybean meal (SBM), and 2) Soybean meal + Wheat bran + Urea (SBM+WB+U). Results. Crude protein (CP) and organic matter intakes were higher (p<0.05) for heifers from SBM compared with SBM+WB+U. The CP digestibility was increased (p<0.05) with SBM supplementation. Mean blood concentrations of glucose, cholesterol, serum urea nitrogen, and total proteins were not affected (p>0.10) by protein sources. In the same way, daily weight gain and final body weight were not influenced (p>0.10) by protein sources. Conclusions. The supplementation with soybean meal or wheat bran with urea in association with soybean meal in multiple supplements for grazing cattle provides similar productive and nutritional performance and metabolic profile in beef heifers.

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