Conception rate and reproductive function of dairy cows fed different fat sources

This study aimed to evaluate the effects of rectal temperature (RT) on conception rate (CR), as well as the effects of seasonality (spring-summer vs. autumn-winter) and timing of artificial insemination (AI) (morning vs. afternoon) on RT and CR in crossbred dairy cows (Holstein x Gyr). The experiment was conducted on a dairy farm in Centralina, MG, where 1,219 conventional and fixed-time inseminations were analyzed. The RT was measured immediately before AI using a digital thermometer. Pregnancy diagnosis was performed using ultrasonography between 28 and 60 days after AI. T The effects of seasonality and timing of AI on RT were analyzed with a Mann-Whitney U test and the effects of RT (above or below the average), seasonality and timing of AI on CR were analyzed with a Chi-squared test, both using the SAS program. The RT average was 39.4°C. Cows with RT ? 39.4°C had lower CR than cows with RT < 39.4°C (25.78% vs. 32.54%; P = 0.0096). During spring-summer, cows had higher RT (39.44°C ± 0.025 vs. 39.27°C ± 0.022; P < 0.0001) and lower CR (25.49% vs. 31.75%; P = 0.0146) compared with autumn-winter. Cows inseminated in the morning had lower RT (38.96°C ± 0.022 vs. 39.60°C ± 0.018; P < 0.0001) and higher CR (32.86% vs. 26.06%; P = 0.0102) than cows inseminated in the afternoon. In conclusion, crossbred dairy cows with rectal temperature equal to or greater than 39.4°C had lower conception rate. Moreover, rectal temperature and conception rate were affected by seasonality and insemination time.

Download Full-text

An investigation of the time period within which frozen-thawed semen delivers a high conception rate in lactating dairy cows

Journal of Reproduction and Development ◽

10.1262/jrd.2019-130 ◽

2020 ◽

Vol 66 (3) ◽

pp. 277-280

Author(s):

Toshiaki SUMIYOSHI ◽

Tomomi TANAKA ◽

Hideo KAMOMAE

Keyword(s):

Dairy Cows ◽

Conception Rate ◽

Lactating Dairy Cows ◽

Time Period

Download Full-text

Reproductive function in average and high yielding dairy cows

BSAP Occasional Publication ◽

10.1017/s0263967x00034194 ◽

2001 ◽

Vol 26 (2) ◽

pp. 495-498 ◽

Cited By ~ 2

Author(s):

Victoria J. Taylor ◽

Andrew J. Hattan ◽

Emma C.L. Bleach ◽

David E. Beever ◽

D. Claire Wathes

Keyword(s):

Dairy Cows ◽

Milk Yield ◽

Post Partum ◽

Reproductive Function ◽

Reproductive Activity ◽

Corpora Lutea ◽

Genetic Merit ◽

Standard Management ◽

Service Conception ◽

The Difference

AbstractThe resumption of reproductive activity in the early post partum period and the subsequent fertility of dairy cows are of considerable practical and economic importance to the producer. Regular milk progesterone analysis was used in this study to monitor the re-establishment of reproductive cyclicity in animals of average (AGM, n=20) and high genetic merit (HGM, n=28) kept under standard management conditions. The profiles obtained were then characterised into normal and four different types of abnormal activity. Resumption of cycles occurred significantly later in the higher yielding cows than in those of average genetic merit (23 ±2.3 days in HGM cows and 15 ± 1.6 days in AGM cows; P=0.0089). There was a significant increase in the amount of abnormal cycles encountered in the high genetic merit animals compared with average yielding animals (61% and 30% respectively; χ2 test, P=0.045); in particular, the delayed occurrence of ovulation post partum (11% vs 0%) and an increased incidence of persistent corpora lutea (32% vs 20%). For high genetic merit animals, the incidence of abnormal cycles was associated with increased peak milkyields (abnormal cycles: peak milk yield 54.7 ± 1.11 kg/day; normal cycles: peak milk yield 46.4 ± 1.35 kg/day, P=0.002). This relationship was not apparent in average genetic merit animals. First service conception rates were 50% (9/18) for AGM cows and 38% (10/26) for HGM cows (χ2 test, n.s.). The calving to conception interval was 98 ± 9.7 days for AGM animals (n=l7) and 105 ± 9.1 days for HGMs (n=24) (t-test, n.s.). In conclusion, this study confirms that high genetic merit dairy cows have compromised reproductive function in terms of a delayed resumption of cyclicity and an increased incidence of abnormal progesterone cycles, which was associated with higher peak milk yields. There was also a reduced first service conception rate in high yielders although the difference was not significant with this group size.

Download Full-text

Risk factors limiting first service conception rate in dairy cows, and their economic impact

Asian-Australasian Journal of Animal Sciences ◽

10.5713/ajas.18.0296 ◽

2018 ◽

Author(s):

Kim Ill-Hwa ◽

Jae Kwan Jeong

Keyword(s):

Risk Factors ◽

Dairy Cows ◽

Economic Impact ◽

Conception Rate ◽

Service Conception

Download Full-text

The effect of feeding intensity during the dry period on plasma leptin and time to return to cyclicity in dairy cows

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200006578 ◽

2002 ◽

Vol 2002 ◽

pp. 1-1 ◽

Cited By ~ 2

Author(s):

K. Holtenius ◽

S. Agenäs ◽

H. Gustafsson ◽

C. Delavaud ◽

Y. Chillard

Keyword(s):

Nutritional Status ◽

Dairy Cows ◽

Body Condition ◽

Reproductive Function ◽

Peptide Hormone ◽

Dry Period ◽

Feeding Intensity ◽

Plasma Leptin ◽

Different Levels ◽

Effect Of Feeding

Much evidence has accumulated showing that female reproductive functions are disrupted when changes in nutritional status take place in both over- and undernutrition. The peptide hormone leptin is considered a possible link between nutrition and reproduction. One objective with the present study was to investigate how different levels of feed intake during the dry period, thereby creating differences in body condition at parturition, affected the plasma leptin concentration and the reproductive function after parturition.

Download Full-text

Comparison of reproductive responses after PGF2α and GnRH-PGF2α oestrous synchronisation schemes in Holstein cows

BSAP Occasional Publication ◽

10.1017/s0263967x00034133 ◽

2001 ◽

Vol 26 (2) ◽

pp. 467-470

Author(s):

J.F. Cox ◽

F. Saravia ◽

O. Torrealba ◽

A. Zavala ◽

A. Lobos

Keyword(s):

Dairy Cows ◽

Corpus Luteum ◽

Detection Efficiency ◽

Post Partum ◽

Conception Rate ◽

Milk Samples ◽

Reproductive Response ◽

Holstein Friesian ◽

Breeding Schemes ◽

Friesian Cows

AbstractControlled breeding schemes for oestrous detection constitutes a proactive technical response that balances the infrastructural requirement for a profitable dairy operation and the demands for optimal animal performance. The present study compared (a) the reproductive response of a treatment based on a short vs longer-acting PGF2α analogue (tiaprost vs luprostiol), and (b) the reproductive response after a treatment of GnRH-PGF2α vs PGF2α alone for synchronizing dairy cows. Holstein-Friesian cows averaging 9000 kg milk/lactation and fed according to their requirements were used in the study. Cows were cyclic, at least 60 days post partum and were clinically sound before being considered for the experiments. In Experiment 1, animals were synchronised using an i.m. injection of either 15 mg of luprostiol or 0.75 mg of tiaprost, based on ultrasonic diagnosis of a corpus luteum. Animals were inseminated at observed oestrus. In Experiment 2, cows were synchronised, at random, by either an injection of 10pg ofbuserelin (day 0) followed by 0.75 mg of tiaprost at day 7 (GnRH-PGF2α) orjust 0.75 mg of tiaprost (PGF2α). For both treatments only cows with an ultrasonically detected corpus luteum were treated. Animals were inseminated at oestrus. At the time of treatment and again 3 days later, milk samples were collected and assayed for progesterone by RIA. Cows with progesterone concentrations >1 ng/ml were considered to have corpus luteum. Luteolysis was considered to have occurred when concentrations of progesterone were > 1 ng/ml at day 0 and <0.8 ng/ml at day 3. In Experiment 1, both analogues gave similar results in terms of induced luteolysis [luprostiol: 36/39 (92.3%) vs tiaprost: 36/41 (87.8%)], oestrous detection efficiency [luprostiol: 26/36 (72.2%) vs tiaprost: 30/36 (83.3%], oestrous distribution [day 2, 3 and 4, respectively: luprostiol: 26.9%, 50.0%, 19.2% vs tiaprost: 36.7%, 50.0%, 13.3%], and conception rates [luprostiol: 12/25 (48.0%) vs tiaprost: 14/28 (50.0%); P>0.05]. In Experiment 2, oestrous detection efficiency, interval to oestrus and conception rate were similar between treatments [97/149 (65.1%), 71.1 h, 43/95 (45.3%) for PGF2α vs 130/188 (69.1%), 68.2h, 65/126 (51.6%) for GnRH-PGF2α, respectively]. However the oestrous distribution was more concentrated in GnRH-PGF2α treated animals (P<0.01).

Download Full-text