Factors affecting fertilisation and early embryo quality in single- and superovulated dairy cattle

2010 ◽  
Vol 22 (1) ◽  
pp. 151 ◽  
Author(s):  
Roberto Sartori ◽  
Michele R. Bastos ◽  
Milo C. Wiltbank
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Embryo Quality ◽  
Early Embryo ◽  
Low Fertility ◽  
Factors Affecting ◽  
Lactating Cows ◽  
Embryo Yield ◽  
Low Concentrations ◽  
High Feed

Data on fertilisation and embryo quality in dairy cattle are presented and the main factors responsible for the low fertility of single-ovulating lactating cows and embryo yield in superovulated dairy cattle are highlighted. During the past 50 years, the fertility in high-producing lactating dairy cattle has decreased as milk production increased. Recent data show conception rates to first service to be approximately 32% in lactating cows, whereas in heifers it has remained above 50%. Fertilisation does not seem to be the principal factor responsible for the low fertility in single-ovulating cows, because it has remained above 80%. Conversely, early embryonic development is impaired in high-producing dairy cows, as observed by most embryonic losses occurring during the first week after fertilisation. However, in superovulated dairy cattle, although fertilisation failure is more pronounced, averaging approximately 45%, the percentage of fertilised embryos viable at 1 week is quite high (>70%). Among the multifactorial causes of low fertility in lactating dairy cows, high feed intake associated with low concentrations of circulating steroids may contribute substantially to reduced embryo quality. Fertilisation failure in superovulated cattle may be a consequence of inappropriate gamete transport due to hormonal imbalances.

Productive and reproductive performance of crossbred and indigenous dairy cows at smallholdings in selected towns of Jimma Zone, Ethiopia

2021 ◽  
Vol 61 (1) ◽  
pp. 92
Author(s):  
Belay Duguma
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Yield ◽  
Reproductive Performance ◽  
Management Practices ◽  
Production Systems ◽  
Management Strategies ◽  
Factors Affecting ◽  
Jimma Zone ◽  
Improvement Programs

Context Evaluation of the performance of dairy cows kept in different production systems is essential for the development of appropriate breeding strategies. Aims To examine milk production and reproductive performance of crossbred (CB) and indigenous (I) dairy cows, farmers’ traits preference for CB and I breeding females, and factors affecting the performance of dairy cattle on smallholdings in selected towns of Jimma Zone, Ethiopia. Methods In total, 52 smallholder dairy cattle farmers were randomly sampled and data were collected through individual face-to-face interviews by using structured questionnaires. The traits studied were daily milk yield (DMY), lactation milk yield (LMY), lactation length (LL), age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO), and number of service per conception (NSC), all being factors affecting performance of dairy cattle and farmers’ preferred dairy traits. Results On average, CB cows had significantly (P < 0.05) higher DMY (6.0 ± 0.33 vs 1.8 ± 0.07 L/cow), LMY (1466.7 ± 1.13 vs 376.0 ± 21.02 L (L)), LL (8.1 ± 0.41 vs 6.9 ± 0.22 months), and lower AFS (2.69 ± 0.1 vs 3.3 ± 0.07 years), AFC (3.7 ± 0.13 vs 4.3 ± 0.07 years) and CI (21.2 ± 1.37 vs 29.8 ± 1.30 months) than did I cows. However, DO and NSC were not significantly (P > 0.05) affected by genotype. In order of perceived importance, high milk yield (mean rank = 0.306), LL (0.292) and fertility (0.199) were farmers’ most preferred traits for CB breeding cows, and the corresponding preferred traits for I cows were high milk yield (0.253), adaptability (0.229) and LL (0.192). The most important factors perceived by farmers affecting the performance of dairy cattle were breed, nutrition, diseases, breeding and management practices Conclusions The findings of the study indicated that even though CB cows performed better, the performance of both breeds of dairy cows in the study area was found to be generally low due to delayed AFS, late AFC, long CI, shorter LL, low daily and LMY and high NSC. Implications The study highlighted that there is a potential for increasing the performance of dairy cows in the study area, through improved management strategies leading to shorter AFS, AFC, CI and lower NSC. Furthermore, future breed-improvement programs should take into consideration farmers’ trait preferences in design of sustainable improvement programs.

10 EFFECT OF USING PROTECTIVE AI COVER SHEATHS ON FERTILITY OF LACTATING DAIRY COWS

2010 ◽  
Vol 22 (1) ◽  
pp. 163
Author(s):  
S. Bas ◽  
A. Hoet ◽  
P. Rajala-Schultz ◽  
D. Sanders ◽  
G. M. Schuenemann
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Dairy Farm ◽  
Cost Effective ◽  
Reproductive Outcomes ◽  
Lactating Cows ◽  
Lactating Dairy Cows ◽  
Herd Milk ◽  
Underlying Mechanisms ◽  
The Moment

An adequate and clean artificial insemination (AI) technique is recommended to maximize reproductive outcomes in dairy cattle. The objective of this study was to evaluate the effectiveness of using protective sheaths (PS; Continental Plastic Inc., Delavan, WI, USA) to minimize contamination of the AI catheter (AIC) on pregnancies per AI (P/AI) in lactating dairy cattle. A previous study reported no improvement on cattle fertility when using PS during first service AI (King et al. 1984 Can. Vet. J. 25, 327). Lactating cows housed in free-stall barns on a commercial dairy farm with a rolling herd milk production average of 10.140 kg were presynchronized with 2 injections of PGF2α (25 mg; Lutalyse, Pharmacia & Upjohn, Kalamazoo, MI, USA) given 14 days apart (starting at 26 ± 3 d postpartum) followed by Ovsynch [OV; GnRH-7 d-PGF2α-56 h-GnRH-16 h-timed-AI(TAI)] 12 days later. Cows presenting signs of standing heat any time during the protocol received AI, whereas the remaining animals were subjected to TAI16 h after second OV GnRH (100 μg; Cystorelin, Merial, Duluth, GA, USA). At the moment of AI (one AI technician), 996 services from lactating dairy cows were randomly assigned to 1 of the 2 groups; with (TRT, n = 487) or without (CON, n = 509) the use of PS. In the TRT group, the AIC protected with a PS was introduced into the vagina; once in the cranial portion of the vagina adjacent to the cervical os, the PS was pulled back and only the AIC was manipulated through the cervix into the uterine body for semen deposition. In the CON group, cows received AI without the PS. Additionally, sterile cotton swab (BD, Franklin Lakes, NJ, USA) samples were taken from AIC (n = 51) after AI from both treatment groups. Pregnancy diagnosis was determined by ultrasonography 42 ± 3 d after AI. Data analyses were performed using GLIMMIX (P/AI) and FREQ (culture) procedures of SAS (SAS Institute Inc., Cary, NC, USA). Cultured swab samples revealed that the use of PS was effective in minimizing contamination of the AIC (bacterial growth on AIC; TRT = 57.7% v. CON = 100%; P < 0.0002). Overall, the proportion of cows pregnant (all services) was greater (P = 0.03) for cows in TRT (42.7 ± 2.2%) compared with CON group (36.1 ± 2.1%). For first services postpartum, P/AI did not differ (P = 0.87) between CON (43.01 ± 4.4%) and TRT (43.8 ± 4.6%) groups. However, P/AI for second or greater services (≥2S) were greater (P = 0.007) in TRT (43.8 ± 2.9%) than in CON cows (32.3 ± 2.6%). Results from this study suggested that the use of PS during AI improved P/AI for ≥2S in lactating dairy cows. Performing a clean AI technique through the use of PS may be a cost-effective strategy to improve reproductive outcomes in dairy cattle. Further investigation is needed under various reproductive management conditions to confirm and determine the underlying mechanisms for these findings. Authors thank Coba/Select Sires Inc. (Columbus, OH, USA) for the donation of the AI protector sheaths, Meerland Dairy for providing the animals and Brian Alkire (Coba’s AI technician).

86 EFFECT OF LACTATION ON EMBRYO DEVELOPMENT DURING THE POSTPARTUM PERIOD IN DAIRY COWS

2012 ◽  
Vol 24 (1) ◽  
pp. 155 ◽  
Author(s):  
V. Maillo ◽  
U. Besenfelder ◽  
V. Havlicek ◽  
M. Garrett ◽  
A. K. Kelly ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Embryo Development ◽  
Metabolic Profile ◽  
Reproductive Tract ◽  
Blastocyst Stage ◽  
Early Embryo ◽  
Blood Samples ◽  
Early Embryo Development ◽  
Lactating Cows

The aim of this study was to examine the effect of lactation and associated metabolic profiles on the ability of the reproductive tract of postpartum dairy cows to support early embryo development. Twenty-one age-matched primiparous Holstein cows were used. Immediately after calving, half of the cows were dried off while the remainder were milked twice daily. To characterise the metabolic profile of the cows, jugular blood samples were taken twice weekly starting 15 days before calving until Day 100 postpartum. At the same time, bodyweight (BW) and body condition score (BCS) were recorded. In Experiment 1, around Day 60 postpartum, the oestrous cycles of all cows were synchronized and sixty-five 2- to 4-cell in vitro-produced embryos were endoscopically transferred on Day 2 (Day 0 = oestrus) to the oviduct ipsilateral to the corpus luteum. On Day 7, the oviduct and uterus were flushed endoscopically and the number of embryos developing to the blastocyst stage was recorded. In Experiment 2, around Day 95 postpartum, cows were re-synchronized and 15 to 20 in vitro-produced blastocysts were transferred to the uterine horn ipsilateral to the corpus luteum. On Day 14, conceptuses were recovered by flushing the reproductive tract at slaughter and were measured. Jugular blood samples were taken daily from Day 0 to 7 (Exp. 1) or 14 (Exp. 2) to measure serum concentrations of progesterone. Data were analysed by ANOVA. Concentrations of NEFA and β-HB were higher (P ≤ 0.05) and glucose, insulin and IGF-1 were lower (P ≤ 0.05) in lactating compared with dry cows. BW and BCS were significantly higher in the non-lactating cows throughout the postpartum period. Recovery rates in both experiments were similar between groups (Exp. 1: 63.9 ± 7.2 vs 65.6 ± 8.6 and Exp 2: 33.3 ± 9.6 vs 39.8 ± 9.6 for dry and milking cows, respectively). In Exp. 1, of the structures recovered, significantly more developed to the blastocyst stage in the dry than in lactating cows (49.3 ± 3.8 vs 32.6.3 ± 4.4, respectively; P ≤ 0.05). Progesterone concentrations did not differ between groups. In Exp. 2, no differences were observed in terms of conceptus dimensions on Day 14 (n = 152). Progesterone concentrations were higher in lactating cows from Day 9 to 14 (P ≤ 0.05). In conclusion, this study provides evidence that at 60 days postpartum, the reproductive tract of lactating cows is compromised in its ability to support early embryo development compared with age-matched parous non-lactating cows; however, by 95 days postpartum there was no apparent difference in conceptus development, consistent with less metabolic stress as indicated by the metabolic profile. Funded by Science Foundation Ireland (SFI/07/SRC/B1156) and the Spanish Ministry of Science and Innovation (AGL2009-11810). VM was supported by an STSM award from the COST Action FAO7O2.

scholarly journals Comparison of mRNA for IGFs and their binding proteins in the oviduct during the peri-oestrous period between dairy heifers and lactating cows

Reproduction ◽  
2011 ◽  
Vol 142 (3) ◽  
pp. 457-465 ◽  
Author(s):  
Theerawat Swangchan-Uthai ◽  
Siobhan W Walsh ◽  
Sarah L H Alexander ◽  
Zhangrui Cheng ◽  
Mark A Crowe ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Early Embryo ◽  
Dominant Follicle ◽  
Embryo Survival ◽  
Lh Surge ◽  
Dairy Heifers ◽  
Lactating Cows ◽  
Holstein Friesian ◽  
Igf Binding ◽  
Igf Binding Protein

The oviduct provides the environment to support gamete maturation, fertilisation and early embryo development. As there is a high incidence of early embryonic death in lactating dairy cows, this study compared expression of IGF family members in the oviduct between lactating Holstein-Friesian dairy cows (n=16, 81±2.4 days in milk) and nulliparous heifers (n=16, age 1.6±0.07 years) at three stages of the oestrous cycle: A) newly selected dominant follicle in the luteal phase, B) follicular phase before the LH surge and C) pre-ovulatory phase after the LH surge. Expression ofIGF1,IGF2, IGF binding protein 2 (IGFBP2),IGFBP3andIGFBP6mRNA was determined in the ampulla of the oviduct. Oviduct side (ipsilateral or contralateral) with respect to the dominant follicle did not affect gene expression. Expression ofIGF1and all threeIGFBPsincreased significantly between the luteal and the pre-ovulatory phases, with no further significant alteration post-LH surge. Concentrations of circulating IGF1 were higher in heifers than in cows, as was the mRNA expression ofIGF1,IGFBP3andIGFBP6. The pre-LH surge rise inIGFBP2mRNA was only observed in heifers.IGF2expression was not influenced by either age or stage of cycle. These three IGFBPs are generally considered to inhibit IGF action. These results indicate tight regulation of IGF bioavailability in the oviductal environment around oestrus, with pronounced differences between cows and heifers, which are likely to influence early embryonic development. Further studies are required to assess the implications for embryo survival.

scholarly journals Period of dominance of the ovulatory follicle influences embryo quality in lactating dairy cows

Reproduction ◽  
2009 ◽  
Vol 137 (5) ◽  
pp. 813-823 ◽  
Author(s):  
Ronaldo L A Cerri ◽  
Heloísa M Rutigliano ◽  
Ricardo C Chebel ◽  
José E P Santos
Keyword(s):  
Dairy Cows ◽  
Artificial Insemination ◽  
Embryo Quality ◽  
Lower Proportion ◽  
Oestrous Cycle ◽  
The Other ◽  
Lactating Cows ◽  
Lactating Dairy Cows ◽  
Ovulatory Follicle ◽  
Timed Artificial Insemination

Length of dominance of the ovulatory follicle and exposure to oestradiol (OE2) during proestrus can affect fertility. Lactating cows had their oestrous cycle pre-synchronized and were subjected to one of the four synchronization treatments. Cows in the oestrus detection (OD) treatment received GnRH on day 6 of the oestrous cycle, PGF2α7 days later, and were inseminated at detected oestrus. The remaining cows were subjected to the Ovsynch (OVS) protocol (day 0 GnRH, day 7 PGF2α, day 9 GnRH, and timed artificial insemination (AI) 12 h later) starting on day 3 (OVS3) or day 6 (OVS6 and OVS6E) of the oestrous cycle. Cows in the OVS6E treatment received an injection of 0.5 mg oestradiol cypionate 36 h before AI. Ovaries were examined by ultrasonography and blood was sampled for progesterone and OE2concentrations. Uteri were flushed 6 days after AI and recovered embryos–oocytes evaluated. Diameter of the ovulatory follicle at AI differed (P<0.01) among treatments, and it was the largest for OVS3 cows, which also had extended (P<0.01) length of follicular dominance. During proestrus, OD and OVS6E cows had increased (P<0.01) OE2concentrations. Fertilization was not altered by treatments, and maximum fertilization was achieved when the number of accessory spermatozoa was >7. Proportions of viable embryos in relation to embryos and embryos–oocytes recovered were smaller for OVS3 cows (P<0.01) than the other treatments, and embryos from OVS3 cows also had fewer (P<0.01) blastomeres and tended (P=0.09) to have a lower proportion of live blastomeres. Extending the period of follicle dominance did not alter fertilization but reduced (P<0.001) embryo quality. Embryo quality was compromised even when the dominance of the ovulatory follicle was extended by only 1.5 days.

127 EFFECT OF DIETARY FATS ON EMBRYO QUALITY AND YIELD IN HEAT-STRESSED DAIRY CATTLE

2011 ◽  
Vol 23 (1) ◽  
pp. 168 ◽  
Author(s):  
Y. Z. Guzey ◽  
A. G. Onal
Keyword(s):  
Dairy Cattle ◽  
Embryo Quality ◽  
Thermal Environment ◽  
Embryonic Cell ◽  
Dietary Fats ◽  
Control Group ◽  
Corpora Lutea ◽  
Embryo Yield ◽  
Cell Counts ◽  
Hot Season

The thermal environment is a major factor that can negatively affect production and reproduction of dairy cattle (Kadzere et al. 2002 Livest. Prod. Sci. 77, 59–91). Heat stress (HS) at and immediately after the time of breeding may result in a lower conception rate (Epperson and Zalesky 2007; http://wrac.sdstate.edu/pubs/ansci/ExEx2018.pdf). High temperatures compromise endometrial function and alter its secretory activity, which may lead to termination of pregnancy (Wolfenson et al. 2000 Anim. Reprod. Sci. 60–61, 535–547). One of the strategies to reduce thermal environment stress is improved nutritional management schemes like increasing dietary fat (Umphrey et al. 2001 J. Dairy Sci. 84, 2680–2685). Our objective was to determine (define) effects of protected fats on ovulation rate, embryo yield, and quality in heat-stressed Holstein cattle in Turkey. Twenty Holstein cows were assigned to control and treatment groups (86.50 ± 8.0 and 83.17 ± 10.8 DIM, respectively). Intravaginal devices (PRID) were placed in all cows (Day 0) and were superstimulated with twice-daily treatments with FSH (5, 4, 3, and 1 mL, respectively) on days 9 to 12. Also cows were treated with PgF2α (Dynolytic, 2 mL) twice on day 11. On the night of day 12, PRID were removed and animals were artificially inseminated on days 13 and 14. On day 20, inseminated cows were palpated per rectum and flushed transcervically. Following uterine flushings, each cows received PgF2α (Dynolytic, 2 mL) to induce luteolysis of developing corpora lutea. Embryos were scored and quantified, and good-quality embryos were fixed to determine embryonic cell counts. Two-twelve cell embryo and blastocyst counts were statistically different between seasons (P < 0.01 and P < 0.05, respectively); only 2-12 cell embryos were different between groups (P < 0.01) and only 2-12 cell embryos were different (P < 0.05) for season × treatment interaction. In the cool season experiment, morula and expanded blastocyst embryos were higher; and in the hot season experiment, unfertilized egg and morula embryos were higher for treatment group than those of controls. Also in the hot season experiment, total embryo yield was higher than the control group. However, dietary fats reduced rectal temperatures in these experiments. According to these results, we can assume that high rectal temperatures caused changes in blood parameters and very early embryonic deaths occurred in the control group. Consequently, dietary fats added to dairy cattle rations in hot seasons can positively affect embryo quality and embryo yield in dairy cattle.

scholarly journals Factors of early embryo mortality incidence in dairy cows

2020 ◽  
Vol 161 ◽  
pp. 01083
Author(s):  
Anatoly Bolgov ◽  
Irina Lepesheva ◽  
Natalia Grishina
Keyword(s):  
Disease Prevention ◽  
Dairy Cows ◽  
Milk Yield ◽  
Early Embryo ◽  
Feeding Frequency ◽  
Embryo Mortality ◽  
Lactating Cows ◽  
Mortality Incidence ◽  
Hereditary Factors ◽  
Autumn And Winter

Early embryo mortality (EEM) is considered to be one of the causes of dairy cows’ productivity reduction. The aim of the research was to study the factors of EEM expansion and the ways to its minimization in order to determine the possibilities of maintaining cows’ productivity. About 4 thousand Ayrshire cows were studied. EEM was registered in 21.7% cows. Low level of EEM was observed in first lactating cows (12.1%), the highest level (27.3%) was registered in old cows (seven lactations and more). Cows with higher productivity are more susceptible to this abnormality: 12.3% of cows with 4500 kg and less of milk yield and 26.5% of cows with milk yield of over 7000 kg. Less cases of embryo mortality are registered during spring and summer seasons of calving (12.0-16.3%) in comparison with autumn and winter ones (19.1-25.7). EEM is observed 1.7 times more in case of deficient feeding than in case of full feeding. Frequency of EEM varied from 5.6 to 44.4% in daughters of different bulls. It is possible to reduce the level of EEM in dairy cows by implementing complex measures of disease prevention and optimization of paratypic, physiological and hereditary factors.

Effects of Retinoic Acid and 1,25-Dihydroxyvitamin D3 on IFN-gamma Secretion by Mononuclear Leukocytes from Nulliparous and Postparturient Dairy Cattle

2000 ◽  
Vol 70 (3) ◽  
pp. 92-101 ◽  
Author(s):  
Burim Ametaj ◽  
Brian Nonnecke ◽  
Ronald Horst ◽  
Donald Beitz
Keyword(s):  
Retinoic Acid ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Dairy Cow ◽  
Pokeweed Mitogen ◽  
Mononuclear Leukocytes ◽  
Combined Effects ◽  
Ifn Gamma ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Individual and combined effects of several isomers of retinoic acid (RA) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on interferon-gamma (IFN-gamma) secretion by blood mononuclear leukocytes (MNL) from nulliparous and postparturient Holstein cattle were evaluated in vitro. In the first experiment, effects on incubation period (24 to 72 hours) and time of supplementation (0 to 32 hours) with all-trans, 9-cis, 13-cis-, and 9,13-dicis-RAs (0 to 100 nM) on IFN-gamma secretion by pokeweed mitogen (PWM)-stimulated (0 and 10 mug/ml) MNL from nulliparous cattle were evaluated. In the second experiment, MNL from postparturient cows (bled at 0, 2, 4, and 16 days postpartum) were stimulated with PWM (0 and 10 mug/ml) in the presence of RA isomers (9-cis- or 9,13-dicis-RA; 0 to 100 nM), 1,25-(OH)2D3 (0 to 100 nM), or with combinations of these metabolites. The results show that individual isomers of RA had no effect on IFN-gamma secretion by PWM-stimulated MNL from nulliparous or postparturient cows. Furthermore 1,25-dihydroxyvitamin D3 inhibited IFN-gamma secretion by MNL from nulliparous and postparturient dairy cows; however, the degree of inhibition was greater when 9-cis- and 9,13-dicis-RA were also present in the cultures. Finally mononuclear leukocytes from postparturient dairy cows produced substantially less IFN-gamma than did MNL from nulliparous cattle. It is concluded that retinoic acids individually did not affect the capacity of leukocytes from dairy cattle to secrete IFN-gamma. This result is in marked contrast to studies in monogastric species indicating that RAs inhibit IFN-gamma secretion by peripheral blood T cells. Inhibition of IFN-gamma secretion by 1,25-(OH)2D3 was potentiated by 9-cis- and 9,13-di-cis-retinoics acids, suggesting that an excess of dietary vitamins A and D may compromise further the naturally immunosuppressed postparturient dairy cow. Additional research is necessary to determine if the combined effects of these metabolites on IFN-gamma secretion represent an increased susceptibility of the dairy cow to infectious diseases during the periparturient period. Lower secretion of IFN-gamma by MNL from postpartutient dairy cows, relative to nulliparous cattle, suggests that recently-calved cows are naturally immunosuppressed.

Factors Affecting the Thyroid Uptake of I131 in Dairy Cows

1957 ◽  
Vol 16 (2) ◽  
pp. 318-327 ◽  
Author(s):  
E. W. Swanson ◽  
F. W. Lengemann ◽  
R. A. Monroe
Keyword(s):  
Dairy Cows ◽  
Factors Affecting ◽  
Thyroid Uptake

COMPARATIVE DESCRIPTION OF MILK PRODUCTIVITY OF COWS UKRAINIAN RED-AND-WHITE DAIRY CATTLE AND UKRAINIAN BLACK-AND-WHITE DAIRY CATTLE AND HOLSTEIN BREEDS IN SERF «OLEKSANDRIVSKE»

2016 ◽  
Vol 52 ◽  
pp. 6-12 ◽  
Author(s):  
M. V. Gladiy ◽  
G. S. Kovalenko ◽  
S. V. Priyma ◽  
G. A. Holyosa ◽  
A. V. Tuchyk ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Yield ◽  
Fat Content ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Black And White ◽  
The Third ◽  
Fat Yield ◽  
Selection Of

The main goal of dairy breeds selection should be improving breeding and productive qualities of animals under modern conditions. The majority of farms, using native breeds to produce milk, has created optimal conditions for keeping and feeding, selection and matching, growing of replacements etc. Further improvement of created native dairy breeds for economically useful traits occurs at total use of purebred Holstein bulls (semen) of foreign selection. In order to realistically assess milk productivity (milk yield, fat content in milk and fat yield) of Ukrainian Black-and-White and Red-and-White Dairy cows should be conducted a comparative analysis of Holstein cows under the same conditions of feeding and keeping. It was established that Ukrainian Red-and-White Dairy cows were characterized by the highest milk yields for 305 days of all lactations, taken into account, the among three investigated breeds. Their milk yield during the first lactation was 5933 kg of milk, during the second – 6393 kg, the third – 6391 kg and during higher lactation – 6650 kg. Ukrainian Black-and-White Dairy cows were second by milk yield (except for the second lactation), during the first lactation – 5932 kg of milk, the third – 6462 kg and higher – 6541 kg, and Holstein cows were third, during the first lactation – 5794 kg of milk, the second – 6381 kg, the third – 6335 kg and higher – 6469 kg. The fat content was almost the same and varied within 3.49-3.58% in milk of Ukrainian Red-and-White Dairy cattle, 3.50-3.60% in milk of Ukrainian Black-and-White Dairy cattle and 3.50-3.56% in Holsteins’ milk. The difference between the breeds was within 0.01-0.04%. All the investigated breeds had predominance in fat yield for three lactations over standards of these breeds: Ukrainian Red-and-White Dairy cows from 75.1 to 93.4 kg, Ukrainian Black-and-White Dairy cows – 75.1-89.0 kg respectively and Holstein cows – 41.9-60.2 kg. It was found different level of positive correlation between milk yield and fat yield in all the cases and high correlation (r = 0.604-0.921, P < 0.001) in five cases (41.7%) Negative correlation coefficients indicate that selection of animals to higher milk yield in the herd will decrease the second trait – fat content in milk. Positive and highly significant correlation between milk yield and fat yield indicates that selection of cows in the herd to higher milk yields will increase fat yield. It was revealed that bulls were among the factors impacted the milk productivity (milk yield, fat content, fat yield) of three investigated breeds. So, the force (η²x) of father’s impact on milk yield was15.4-47.9%, fat content – 22.0-43.4% and fat yield – 14.9-47.7% taking into account a lactation and a breed. The force of lines impact (η²x) was second; it was on milk yield 6.1-24.5%, fat content – 4.1-17.1 and fat yield – 5.8-23.5%. The force of breeds impact (η²x) was last; it was on milk yield 0.3-2.9%, fat content – 0.2-0.3% and fat yield – 0.6-2.7%. So, the comparative studies of milk productivity of Ukrainian Red-and-White and Black-and-White Dairy cattle with Holsteins indicate that under similar conditions of feeding and keeping, these native breeds can compete with Holstein cattle. The milk yield for 305 days of higher lactation was 6650 kg of milk in Ukrainian Red-and-White Dairy cows, 6541 kg in Ukrainian Black-and-White Dairy cows and 6469 kg in Holsteins. It was found the inverse correlation r = -0.025-0.316 between milk yield and fat content in milk in most cases. Selection and matching of animals in the herd should be carried out simultaneously on these traits. It was found positive repeatability of milk yields between the first and second, the third and higher lactations (rs = 0.036-0.741), indicating the reliability of forecasting increase in milk productivity during the next lactations in all herd. Bulls have the greatest impact (η²x) on milk productivity among the factors taken into account: milk yield – 15.4-47.9%, fat content in milk – 22.0-43.4% and fat yield – 14.9-47.7%.

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