Livestock Research Branch

Edmonton, Canada

Livestock Research Branch

Edmonton, Canada
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Colazo M.G.,Livestock Research Branch | Dourey A.,University of Alberta | Rajamahendran R.,University of British Columbia | Ambrose D.J.,Livestock Research Branch | Ambrose D.J.,University of Alberta
Theriogenology | Year: 2013

One of the causes of poor fertility in high producing dairy cows is inadequate progesterone. Therefore, we determined the efficacy of an intravaginal insert containing 1.55 g of progesterone (PRID) given before and/or after timed AI (TAI) on ovarian response, plasma progesterone concentrations, pregnancy per AI (P/AI) and pregnancy losses. Lactating dairy cows at three locations were assigned (Day 0) to an Ovsynch protocol with (N = 294) or without (N = 314) a PRID. The Ovsynch protocol consisted of two injections of 100 μg gonadorelin (GnRH) 9 days apart and one injection of 500 μg cloprostenol (PG) 7 days after the first GnRH treatment. Insertion and removal of PRID occurred concurrent with the first GnRH and PG treatments, respectively. Timed AI was carried out 12 to 16 hours after the second GnRH. Ovarian status of a subset of 217 first service cows had been presynchronized with 2 treatments of PG 14 days apart with the last PG given 12 days before the first GnRH of the Ovsynch protocol. Body condition score (scale of one to five) was recorded at TAI. Ultrasonographic examinations were done in all cows at first GnRH, at PG, at TAI, and 24 hours after TAI for response to treatment and at 32 and 60 days after TAI for confirmation of pregnancy. At 4.5 days after TAI (Day 14), cows that responded to PG and ovulated after the second GnRH treatment were reassigned to receive (N = 223) or not receive (N = 229) a PRID for 7 days. Blood samples were taken for progesterone determination at PG treatment, at TAI, and post TAI on Days 14 and 21. The PRID treatment pre-TAI reduced the percentage of cows ovulating before TAI (5.8% vs. 11.1%), and significantly increased P/AI in nonpresynchronized cows (41.3% vs. 25.1%). Cows ovulating in response to the first GnRH treatment, cyclic cows, and cows with body condition score of 2.75 or more had increased P/AI, but the addition of a PRID pre-TAI to these cows did not increase P/AI. The PRID treatment post TAI did not affect P/AI, but reduced pregnancy losses (6.1% vs. 11.4%) between 32 and 60 days of gestation. The reduction in pregnancy losses tended (P = 0.10) to be significant in acyclic cows receiving a PRID than in those not receiving a PRID (5.6% vs. 33.3%). Plasma progesterone concentrations at PG treatment and on Day 21 (11.5 days after TAI) were linearly associated with P/AI. In conclusion, progesterone supplementation pre-TAI increased P/AI in nonpresynchronized cows. Progesterone supplementation post TAI reduced pregnancy losses, particularly in acyclic cows. © 2013 Elsevier Inc.


In the present study, we determined the effects of maternal dietary fat and the type of fat on plasma fatty acids and the expression of placental fatty acid transporter genes. In Experiment 1, Holstein cows in the last 35 days of gestation received diets containing sunflower seed (n≤8; high in linoleic acid (LA)), canola seed (n≤7; high in oleic acid (OLA)) or no oilseed (n≤7; control). Fatty acids were quantified in dam and neonate plasma at calving. In Experiment 2, placental cotyledons were collected (LA: n≤4; OLA: n≤4; control: n≤5) to quantify gene expression. Maternal long-chain polyunsaturated fatty acids, neonatal total n-3 fatty acids and eicosapentaenoic acid (EPA) declined, whereas docosahexaenoic acid (DHA) and total fat tended to decline following fat supplementation prepartum. Feeding of LA versus OLA prepartum tended to increase peroxisome proliferator-activated receptor α (PPARA) expression, whereas peroxisome proliferator-activated receptor δ (PPARD) and peroxisome proliferator-activated receptor γ (PPARG) expression tended to be higher in OLA- than LA-fed cows. Expression of fatty acid transporter protein 4 (FATP4) and fatty acid translocase (FAT/CD36) expression was lower in placental tissue of cows fed fat compared with control cows. Reduced total n-3 fatty acids, EPA and DHA in neonates born of dams fed fat prepartum is likely due to changes in PPARs and reduced expression of placental FATP4 and FAT/CD36. © CSIRO 2017.


Bench C.J.,University of Alberta | Oryschak M.A.,Livestock Research Branch | Korver D.R.,University of Alberta | Beltranena E.,Livestock Research Branch
Canadian Journal of Animal Science | Year: 2017

Perches serve as a behavioural enrichment and may yield benefits on broiler foot health and growth performance. The benefit may be greater for birds fed high crude protein (HCP) diets, which results in poorer litter conditions. This study investigated the effect of two perch configurations (I shaped vs. X shaped, compared with no perch) and dietary crude protein (CP) level (standard vs. high) on behaviour, foot pad health, bone density, growth performance, and carcass traits of broilers raised to 35 d of age. Perch configuration did not affect body weight (BW) at day 35 or overall average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). Likewise, there was no effect of perch provision independent of CP level for any carcass variable. Feeding standard CP (SCP) level resulted in greater bone density, carcass weight, and dressing percentage but lower breast, wing, and total edible meat yield. We confirmed that greater litter moisture (16%) related to excess dietary CP (13%) caused footpad dermatitis in broilers trending from 3 wk old to significant at 27 and 35 d of age. Provision of barrier perches did not reprieve from litter contact (perching), although more focal birds were observed resting against them and did not affect growth performance, bone density, or carcass traits. © 2017, Agricultural Institute of Canada. All rights reserved.


Dirandeh E.,Sari University of Agricultural Sciences and Natural Resources | Roodbari A.R.,University of Tehran | Colazo M.G.,Livestock Research Branch
Theriogenology | Year: 2015

The objective was to compare 3 timed artificial insemination (TAI) protocols in lactating dairy cows during heat stress. Multiparous Holstein cows yielding (mean±SEM) 29.4±0.3kg of milk/d randomly were assigned to 1 of 3 TAI protocols at 34±5.1days in milk: 1) double-Ovsynch (DO; n=486): the cows received GnRH-7d-2α-3d-GnRH and Ovsynch56 (GnRH-7d-PGF2α-56h-GnRH-16h-AI) was initiated 7days later; 2) Presynch-GnRH-Ovsynch (PGO; n=453): the cows received PGF2α-14d-PGF2α-2d-GnRH and Ovsynch56 was initiated 7days later; and 3) presynch-Ovsynch (PO; n=435): the cows received PGF2α-14d-PGF2α and Ovsynch56 was initiated 12days later. The ovulatory response to the first GnRH of Ovsynch56 was higher in DO (65.0%) compared to PGO (53.2%) and PO (45.5%). Luteolytic response to PGF2α of Ovsynch was similar among TAI protocols (90.1%, 87.1%, and 86.2% for DO, PGO, and PO, respectively). Synchronization rate was greater in DO (86.2%) than in PGO (78.1%) and PO (72.1%) protocols. Irrespective of the TAI protocol, cows that ovulated in response to first GnRH had greater response to PGF2α (92.7 vs. 77.1%). Mean (±SEM) diameter (mm) of ovulatory follicle at TAI was larger in DO (16.1±0.3) than PGO (15.6±0.21) and PO (15.2±0.12). Cows subjected to DO had greater P/AI at 32days and at 60days after TAI (26.6 and 24.4%) compared with those in PGO (21.4 and 20.0%) and PO (17.2 and 15.9%). However, TAI protocol had no significant effect on the incidence of pregnancy loss (6.1%, 6.6%, and 7.4% for DO, GO, and PO, respectively). In summary, cows in the DO protocol had a greater ovulation rate to the first GnRH and a greater synchronization rate, larger ovulatory follicles and greater P/AI. Of the 3 protocols used, DO yield the best reproductive performance in heat-stressed, lactating dairy cows. © 2015 Elsevier Inc.


Colazo M.G.,Livestock Research Branch | Ambrose D.J.,Livestock Research Branch | Ambrose D.J.,University of Alberta
Theriogenology | Year: 2011

Our objectives were to: 1) compare response to cloprostenol, synchrony of ovulation, and pregnancy per timed-AI (P/TAI) in a 5 d versus a 7 d Co-synch + PRID protocol (Experiment 1); and 2) investigate whether the initial GnRH is necessary to achieve acceptable P/TAI in a 5 d Co-synch + PRID protocol (Experiment 2) in dairy heifers. In Experiment 1, 64 Holstein heifers, 15 to 17 mo, were assigned by age to receive 100 μg of GnRH and a PRID for 5 or 7 d (PRID5 and PRID7, respectively). At PRID removal 500 μg of cloprostenol (PGF) was given i.m. Heifers received the second GnRH treatment concurrently with TAI at 72 (PRID5) or 56 (PRID7) h after PRID removal. Transrectal ultrasonography monitored ovarian dynamics, ovulation synchrony, and pregnancy status (28 and 45 d after TAI). Plasma progesterone concentrations were determined at PRID removal and TAI. Five of seven heifers that ovulated before TAI became pregnant, and only two heifers did not respond to PGF treatment in the PRID5 group. Five PRID5 and 2 PRID7 heifers failed to ovulate after the second GnRH. However, P/TAI did not differ between PRID5 (59.4%) and PRID7 (58.1%). Overall ovulation response to first GnRH treatment was only 31.7%, and a larger proportion of heifers that did not ovulate became pregnant (65.1 versus 45.0%). In Experiment 2, 56 Holstein heifers, assigned as in Experiment 1, were subjected to a PRID5 protocol with (PRID5G) or without (PRID5NoG) GnRH at PRID insertion; all heifers were TAI 72 h after PRID removal. Transrectal ultrasonography and progesterone determinations were performed as in Experiment 1. Pregnancy per TAI did not differ whether or not heifers received GnRH at PRID insertion (67.9 versus 71.4%). Consistent with our previous findings, seven of nine heifers that ovulated before TAI became pregnant, and only two heifers did not respond to PGF treatment. Combining both experiments, length of proestrus but not ovulatory follicle diameter was identified as a significant predictor of probability of pregnancy 28 d after TAI, with a maximum predicted probability of 80.1% when the length of proestrus was 3 d. In summary, a PRID5 protocol resulted in comparable P/TAI to a PRID7 protocol. Most of the heifers that ovulated before TAI in the PRID5, PRID5G, and PRID5NoG protocols became pregnant. More than one PGF or a GnRH treatment at PRID insertion in a 5 d Co-synch + PRID protocol was not required to achieve acceptable P/TAI in dairy heifers. © 2011 Elsevier Inc.


Colazo M.G.,Livestock Research Branch | Behrouzi A.,Livestock Research Branch | Ambrose D.J.,Livestock Research Branch | Ambrose D.J.,University of Alberta | Mapletoft R.J.,University of Saskatchewan
Theriogenology | Year: 2015

Ovulation of an early-stage dominant follicle induced by exogenous GnRH reportedly results in a reduced ovulatory follicle size and fertility in beef and dairy cattle. Objectives were to examine factors associated with ovulatory follicle diameter and the relationship between ovulatory follicle diameter and pregnancy per artificial insemination (P/AI) and pregnancy loss in lactating dairy cows subjected to GnRH-based programs for timed artificial insemination (TAI). A total of 1048 ovulations from 1576 breedings of cows that had or had not been presynchronized and subjected to a 5- or a 7-day GnRH-based protocol with or without progesterone supplementation between initial GnRH and PGF2a were analyzed. Ultrasonography was used to determine cyclicity, ovulation, and pregnancy status and to measure diameter of the ovulatory follicle at the time of TAI. Mean (± standard error) diameter of the ovulatory follicle was 16.4 ± 0.1 mm (range, 11-25 mm; n = 1048); the most common diameters were 15 (n = 170), 16 (n = 169), and 17 mm (n = 170). Multiparous cows and those subjected to a 7-day protocol had larger ovulatory follicles (P < 0.05). On average, multiparous cows that did not ovulate after the initial GnRH had the largest ovulatory follicles (17.0 ± 0.1 mm; n = 290), whereas all cows that ovulated after the initial GnRH and were subjected to a 5-day GnRH-based protocol had the smallest ovulatory follicles (15.6 ± 0.2 mm; n = 207). The associations between ovulatory follicle diameter and P/AI at 32 and 60 days after TAI were not significant. However, a significant linear relationship between ovulatory follicle diameter and pregnancy loss between 32 and 60 days after TAI was observed, with an increased (P < 0.05) probability of pregnancy loss in cows with an ovulatory follicle greater than 20 mm in diameter. In summary, the diameter of the ovulatory follicle preceding TAI was affected by interactions between ovulatory response to initial GnRH and parity and between ovulatory response to initial GnRH and the length of ovulation synchronization protocol. Ovulatory follicle diameter was not associated with P/AI at 32 or 60 days, but large ovulatory follicle size was identified as a predictor of pregnancy loss in lactating dairy cows subjected to GnRH-based protocols for TAI. © 2015 Elsevier Inc.


Colazo M.G.,Livestock Research Branch | Ponce-Barajas P.,University of Alberta | Ambrose D.J.,Livestock Research Branch | Ambrose D.J.,University of Alberta
Journal of Dairy Science | Year: 2013

A protocol for presynchronization of ovarian status with 2 injections of PGF2α given 14d apart, with the last PGF2α injection given 12 or 14d before Ovsynch increases pregnancy per artificial insemination (P/AI) in dairy cows. We determined the efficacy of reducing the interval from the last PGF2α injection (500μg of cloprostenol) of presynchronization to initiation of Ovsynch on response to treatment and P/AI. Lactating dairy cows were assigned to an Ovsynch protocol, with the initial injection of GnRH given either 9 (PRE-9; n=135) or 12d (PRE-12; n=135) after the second PGF2α injection of presynchronization. The Ovsynch protocol consisted of 2 injections of 100μg of GnRH given 9d apart and 1 injection of PGF2α given 7d after the initial GnRH injection, and cows were subjected to timed artificial insemination (TAI; 70±3.5 DIM) approximately 16h after the second GnRH injection. Body condition score (1-5 scale) was recorded at TAI. Blood samples were taken for progesterone determination at the PGF2α injection of Ovsynch, at TAI, and at 11d after TAI. Ultrasonographic examinations were done in all cows at the second PGF2α injection of presynchronization, initial GnRH injection, PGF2α injection of Ovsynch, at TAI, and 24h after TAI for cyclicity status and ovarian responses to treatments, and at 32 and 60d after TAI for confirmation of pregnancy. Overall, 29 cows (10.7%) were determined acyclic or cystic and excluded from the study. The percentage of cows responding to initial GnRH injection (62.2 vs. 61.5%) did not differ between PRE-9 and PRE-12 but more cows in the PRE-9 group failed to respond to PGF2α treatment of Ovsynch compared with PRE-12 (22.7 vs. 10.7%). Body condition score at TAI (2.9±0.02) and mean ovulatory follicle diameter (16.4±0.2mm) were not different between treatments. Overall P/AI at 32d was reduced in PRE-9 (33.6%) compared with PRE-12 (44.3%) but pregnancy losses (5.0 vs. 3.7%) did not differ between treatments. Primiparous cows in the PRE-12 group had higher mean progesterone concentration 11d after TAI and greater P/AI 32 after TAI than primiparous cows in the PRE-9 group (6.4±0.5 vs. 4.6±0.5ng/mL and 55.8 vs. 30.0%, respectively). In conclusion, reducing the interval from the last PGF2α injection of the presynchronization treatment to initiation of Ovsynch (from 12 to 9d) did not affect ovulatory response to initial GnRH injection but reduced response to PGF2α injection of Ovsynch and P/AI at 32 and 60d after TAI. The reduction in P/AI was particularly evident in primiparous cows of the PRE-9 group. © 2013 American Dairy Science Association.


Zuidhof M.J.,University of Alberta | Schneider B.L.,Livestock Research Branch | Carney V.L.,Livestock Research Branch | Korver D.R.,University of Alberta | Robinson F.E.,University of Alberta
Poultry Science | Year: 2014

The effect of commercial selection on the growth, efficiency, and yield of broilers was studied using 2 University of Alberta Meat Control strains unselected since 1957 and 1978, and a commercial Ross 308 strain (2005). Mixed-sex chicks (n = 180 per strain) were placed into 4 replicate pens per strain, and grown on a current nutritional program to 56 d of age. Weekly front and side profile photographs of 8 birds per strain were collected. Growth rate, feed intake, and measures of feed efficiency including feed conversion ratio, residual feed intake, and residual maintenance energy requirements were characterized. A nonlinear mixed Gompertz growth model was used to predict BW and BW variation, useful for subsequent stochastic growth simulation. Dissections were conducted on 8 birds per strain semiweekly from 21 to 56 d of age to characterize allometric growth of pectoralis muscles, leg meat, abdominal fat pad, liver, gut, and heart. A novel nonlinear analysis of covariance was used to test the hypothesis that allometric growth patterns have changed as a result of commercial selection pressure. From 1957 to 2005, broiler growth increased by over 400%, with a concurrent 50% reduction in feed conversion ratio, corresponding to a compound annual rate of increase in 42 d live BW of 3.30%. Forty-two-day FCR decreased by 2.55% each year over the same 48-yr period. Pectoralis major growth potential increased, whereas abdominal fat decreased due to genetic selection pressure over the same time period. From 1957 to 2005, pectoralis minor yield at 42 d of age was 30% higher in males and 37% higher in females; pectoralis major yield increased by 79% in males and 85% in females. Over almost 50 yr of commercial quantitative genetic selection pressure, intended beneficial changes have been achieved. Unintended changes such as enhanced sexual dimorphism are likely inconsequential, though musculoskeletal, immune function, and parent stock management challenges may require additional attention in future selection programs. © 2014 Poultry Science Association Inc.


PubMed | Livestock Research Branch and University of Alberta
Type: Journal Article | Journal: Theriogenology | Year: 2016

In a previous work, using porcine LH (pLH) in lieu of GnRH for synchronizing ovulation in dairy cows improved pregnancy rates without increasing plasma progesterone concentrations after ovulation. The LH profile is known to remain elevated above basal concentrations (1ng/mL) for up to 20hours in pLH-treated cows compared to less than 6hours in GnRH-treated cows. Because LH triggers a cascade of signaling networks in the preovulatory follicle to promote final maturation and support oocyte competence, we hypothesized that dissimilar LH profiles will differentially regulate the intrafollicular factors and expression of downstream genes associated with improved oocyte competence. Specific objectives were to determine differences in the abundance of oocyte-secreted factors in the preovulatory follicular fluid and target genes in granulosa cells associated with oocyte competence, in response to exogenous porcine LH or GnRH-induced endogenous bovine LH exposure, in dairy cows. Follicular contents were aspirated by a transvaginal ultrasound-guided procedure from the preovulatory follicle of cyclic, nonlactating Holstein cows 21 1 hour after administration of either pLH (25-mg) or GnRH (100-g). Mature forms of bone morphogenetic protein 15, growth differentiation factor 9, and transforming growth factor1 were approximately 2-fold more abundant in pLH-treated cows which were exposed to an extended, low LH profile, than in GnRH-treated cows that had a short, high LH profile. The relative abundance of messenger RNA for cyclooxygenase-2, LH receptor, and progesterone receptor in granulosa cells, was about two-, eight-, and two-fold higher, respectively, in cows subjected to pLH than GnRH treatment. We infer that the improved pregnancy rate after pLH-induced ovulation reported previously, occurred through greater activation of intrafollicular transforming growth factor-1 superfamily members, as these proteins promote cumulus expansion and oocyte competence.


PubMed | Livestock Research Branch and University of Alberta
Type: Journal Article | Journal: Journal of dairy science | Year: 2016

Our objective was to evaluate the effects of dietary starch content, altered by partial substitution of dietary grain with wheat dried distillers grain with solubles (DDGS), on the interval from calving to first ovulation, concentrations of hormones and metabolites in plasma and follicular fluid, and granulosa cell gene expression in preovulatory follicles. Sixty lactating dairy cows were assigned to 1 of 2 diets from calving until 84d postpartum. Diets were formulated to contain either 17.3% rolled barley grain (29.2% starch) or 17.2% wheat DDGS (19.1% starch), with 43.0% barley silage and 21.6% rolled corn grain as the other major ingredients (dry matter basis). Transrectal ultrasonography was performed twice weekly to monitor ovarian dynamics from 7 2d postpartum until ovulation or until 56d in milk, whichever occurred earlier. Plasma concentrations of insulin and insulin-like growth factor-1 (IGF-1) were determined in all 60 cows, and that of glucose, fatty acids, and urea in a subset of 24 cows, representing those in which the first ovulation occurred spontaneously within 5 wk postpartum. Estradiol (proestrus) and progesterone (12d postovulation) in plasma were also measured. Concentrations of insulin, IGF-1, glucose, fatty acids, and urea were determined in follicular fluid (wk 9), and the expression of LH receptor, estrogen receptor , cytochrome P450 aromatase, and plasma type glutathione peroxidase genes measured in granulosa cells obtained from the preovulatory follicles at wk 9 postpartum in the subset of 24 cows. Diets did not alter the interval from calving to first ovulation (32.3 2.5d), but a significantly lower proportion of cows on the DDGS diet (20%) ovulated multiple ( 2) follicles at the first ovulation than those on the barley grain diet (40%). The incidence of multiple ovulations tended to be lower at first insemination (10 vs. 21% for cows fed DDGS and barley grain diets, respectively). Mean plasma concentration of insulin was higher in cows fed the barley grain diet (2.5 vs 1.6 IU/mL), and a diet by time interaction was noted, with cows on the barley grain ration having higher insulin from wk 6 to 12 postpartum; however, mean plasma IGF-1 concentration did not differ between dietary groups. In the subsets, mean plasma concentrations of metabolites or estradiol and progesterone were not affected by diet, parity, or diet by parity interactions. Cows on the DDGS diet had lower concentrations of IGF-I (69 vs. 108 ng/mL) and higher fatty acids (222 vs. 149 mEq/L) in the follicular fluid obtained from preovulatory follicles. Diet, parity, and diet by parity interactions did not affect the concentrations of insulin, glucose, urea, estradiol, and progesterone in follicular fluid. Diets did not alter the expression profiles of LHr, estrogen receptor , CYP19, and GPx3 genes in granulosa cells. In summary, diets did not affect the interval from calving to first ovulation or granulosa cell gene expression. However, reducing dietary starch content by a partial replacement of dietary grain with wheat DDGS increased fatty acids in follicular fluid and reduced the concentrations of insulin in plasma, IGF-1 in follicular fluid, and the incidence of multiple ovulations.

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