Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==follicular development
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Should Weaning be the Start of the Reproductive Cycle in Hyper-prolific Sows? A Physiological View
Kemp, B. ; Soede, N.M. - \ 2012
Reproduction in Domestic Animals 47 (2012)Suppl. 4. - ISSN 0936-6768 - p. 320 - 326.
lactating primiparous sows - to-estrus interval - litter size - follicular development - feeding level - altrenogest treatments - progestagen treatment - endocrine changes - embryo survival - 1st-litter sows
Normally, sows are in anoestrus during lactation and start their new cycle at the day of weaning. Modern hybrid primiparous sows that suckle large numbers of piglets may lose substantial amounts of body reserves during lactation. This compromises follicle development during lactation. As modern sows have short weaning-to-oestrus intervals, these compromised follicles are recruited for ovulation directly after weaning, resulting in lower ovulation rates and lower embryo survival. Postponing or skipping first oestrus after weaning in primiparous sows may help to limit the negative consequences of lactation on subsequent reproduction. Multiparous sows may have very high litter sizes, especially after long lactations as applied in organic sows. These high litter sizes compromise piglet birthweight and survival and subsequent performance. Inducing lactation oestrus in multiparous sows may help to limit litter size and improve piglet survival and performance. This study discusses physiological and reproductive effects of extending the start of a new pregnancy after lactation in primiparous sows and induction of lactation oestrus in multiparous sows. We thereby challenge the view that weaning is an ideal start for the reproductive cycle in modern sows.
Progestagen Supplementation During Early Pregnancy does not Improve Embryo Survival in Pigs
Soede, N.M. ; Bouwman, E.G. ; Laan, I. van der; Hazeleger, W. ; Jourquin, J. ; Langendijk, P. ; Kemp, B. - \ 2012
Reproduction in Domestic Animals 47 (2012)5. - ISSN 0936-6768 - p. 835 - 841.
accessory sperm count - to-conception interval - primiparous sows - altrenogest treatment - exogenous progesterone - follicular development - fertilization rate - lactation length - ovarian-function - litter size
Progesterone supplementation during early pregnancy may increase embryo survival in pigs. The current study evaluated whether oral supplementation with an analogue of progesterone, altrenogest (ALT), affects embryo survival. A first experiment evaluated the effect of a daily 20-mg dosage of ALT during days 1–4 or 2–4 after onset of oestrus on embryo survival at day 42 of pregnancy. A control group (CTR1) was not treated. The time of ovulation was estimated by transrectal ultrasound at 12-h intervals. Altrenogest treatment significantly reduced pregnancy rate when start of treatment was before or at ovulation: 25% (5/20) compared to later start of treatment [85% (28/33)] and non-treated CTR1 [100% (23/23)]. Altrenogest treatment also reduced (p <0.05) number of foetuses, from 14.6 ± 2.6 in CTR1 to 12.5 ± 2.5 when ALT started 1–1.5 days from ovulation and 10.7 ± 2.9 when ALT started 0–0.5 days from ovulation. In a second experiment, sows with a weaning-to-oestrous interval (WOI) of 6, 7 or 8–14 days were given ALT [either 20 mg (ALT20; n = 49) or 10 mg (ALT10; n = 48)] at day 4 and day 6 after onset of oestrus or were not treated (CTR2; n = 49), and farrowing rate and litter size were evaluated. Weaning-to-oestrous interval did not affect farrowing rate or litter size. ALT did not affect farrowing rate (86% vs 90% in CTR2), but ALT20 tended to have a lower litter size compared with CTR2 (11.7 ± 4.1 vs 13.3 ± 3.1; p = 0.07) and ALT10 was intermediate (12.3 ± 2.9). In conclusion, altrenogest supplementation too soon after ovulation reduces fertilization rate and embryo survival rate and altrenogest supplementation at 4–6 days of pregnancy reduces litter size. As a consequence, altrenogest supplementation during early pregnancy may reduce both farrowing rate and litter size and cannot be applied at this stage in practice as a remedy against low litter size.
Reproductive cycles in pigs
Soede, N.M. ; Langendijk, P. ; Kemp, B. - \ 2011
Animal Reproduction Science 124 (2011)3-4. - ISSN 0378-4320 - p. 251 - 258.
growth-factor-i - porcine corpora-lutea - dietary energy-source - 2 feeding levels - luteinizing-hormone - primiparous sows - follicular development - estrous-cycle - ovulation rate - pulsatile release
The oestrous cycle in pigs spans a period of 18–24 days. It consists of a follicular phase of 5–7 days and a luteal phase of 13–15 days. During the follicular phase, small antral follicles develop into large, pre-ovulatory follicles. Being a polytocous species, the pig may ovulate from 15 to 30 follicles, depending on age, nutritional status and other factors. During the luteal phase, follicle development is less pronounced, although there is probably a considerable turnover of primordial to early antral follicles that fail to further develop due to progesterone inhibition of gonadotrophic hormones. Nevertheless, formation of the early antral follicle pool during this stage probably has a major impact on follicle dynamics in the follicular phase in terms of number and quality of follicles. Generally, gilts are mated at their second or third estrous cycle after puberty. After farrowing, pigs experience a lactational anoestrus period, until they are weaned and the follicular phase is initiated, resulting in oestrus and ovulation 4–7 days after weaning. This paper describes the major endocrine processes during the follicular and luteal phases that precede and follow ovulation. The role of nutrition and metabolic status on these processes are briefly discussed
Dietary Energy Source in Dairy Cows in Early Lactation: Energy Partitioning and Milk Composition
Knegsel, A.T.M. van; Brand, H. van den; Dijkstra, J. ; Straalen, W.M. van; Heetkamp, M.J.W. ; Tamminga, S. ; Kemp, B. - \ 2007
Journal of Dairy Science 90 (2007)3. - ISSN 0022-0302 - p. 1467 - 1476.
fatty-acid-composition - follicular development - metabolic-disorders - ovarian-function - cattle - balance - digestion - glucose - concentrate - hormones
Metabolic problems related to negative energy balance suggest a role for the balance in supply of lipogenic and glucogenic nutrients. To test the effect of lipogenic and glucogenic nutrients on energy partitioning, energy balance and nitrogen balance of 16 lactating dairy cows were determined by indirect calorimetry in climate respiration chambers from wk 2 to 9 postpartum. Cows were fed a diet high in lipogenic nutrients or a diet high in glucogenic nutrients from wk 3 prepartum until wk 9 postpartum. Diets were isocaloric (net energy basis) and equal in intestinal digestible protein. There was no effect of diet on metabolizable energy intake and heat production. Cows fed the lipogenic diet partitioned more energy to milk than cows fed the glucogenic diet [1,175 ± 18 vs. 1,073 ± 12 kJ/(kg0.75·d)] and had a higher milk fat yield (1.89 ± 0.02 vs. 1.67 ± 0.03 kg/d). The increase in milk fat production was caused by an increase in C16:0, C18:0, and C18:1 in milk fat. No difference was found in energy retained as body protein, but energy mobilized from body fat tended to be higher in cows fed the lipogenic diet than in cows fed the glucogenic diet [190 ± 23 vs. 113 ± 26 kJ/(kg0.75·d)]. Overall, results demonstrate that energy partitioning between milk and body tissue can be altered by feeding isocaloric diets differing in lipogenic and glucogenic nutrient content.
The effect of the supply of rumen degradable protein and metabolisable protein on negative energy balance and fertility in dairy cows
Tamminga, S. - \ 2006
Animal Reproduction Science 96 (2006)3-4. - ISSN 0378-4320 - p. 227 - 239.
milk urea nitrogen - reproductive-performance - dietary-protein - lactating cows - follicular development - calving intervals - fatty-acids - cattle - nutrition - plasma
Reproduction in dairy cattle is negatively affected by a negative energy balance (NEB), a combination of the deposition or mobilisation of fat and protein. The mode of action of NEB on fertility is not always clear, but the severity, length, and probably also the nature of the NEB may be involved. Extensive mobilisation of fat is expected to have detrimental effects on liver function due to the accumulation of non-esterified long chain fatty acids, impairing the detoxification of ammonia into urea. Protein evaluation systems nowadays use the concept of metabolisable protein (MP) and distinguish between rumen degradable protein (RDP) and rumen undegradable protein (RUP). Mobilisation of protein itself does not seem to have negative effects on reproduction. However, when protein is extensively degraded in the rumen or used as an energy source, metabolic residues like ammonia and urea will result. Such residues may exert metabolic effects that are often detrimental to reproduction and fertility. Ammonia is believed to play a role starting before ovulation, whereas urea mainly interferes negatively after fertilisation. But, urea is also believed to aggravate the severity of NEB and its effect on fertility by preventing or delaying the start of cyclicity. Besides, urea has been shown to lower the pH in the uterine fluid, giving rise to disturbances in follicular development and embryonic growth. It is recommended to limit the level of rumen degradable protein in the diet to 10% in the DM
Supplementation of dextrose to the diet during the weaning to estrus interval affects subsequent variation in within-litter piglet birth weight
Brand, H. van den; Soede, N.M. ; Kemp, B. - \ 2006
Animal Reproduction Science 91 (2006)3-4. - ISSN 0378-4320 - p. 353 - 358.
early embryonic diversity - energy-source - primiparous sows - follicular development - luteinizing-hormone - exogenous insulin - ovulation rate - growth - gilts - pigs
Effects of supplementation of dextrose to the diet of sows during the weaning-to-estrus interval (WEI) on subsequent litter size and within-litter variation were investigated. After weaning, 223 sows (first to fifth parity) were fed 3.5 kg/d. Half of the sows additionally received 150 g of dextrose per day as topdressing on the feed. WEI and estrus duration were determined as well as subsequent pregnancy rate and litter size. Piglets were weighed individually at birth and at weaning (day 26.4; S.D.: 2.5). Supplementation of dextrose to the diet during the WEI did not affect WEI (106 h), pregnancy rate (88.2%), farrowing rate (84.2%), subsequent litter size (total born: 13.70), or birth weight (1599 g). The within-litter variation in birth weight was lower in sows on the dextrose treatment (CV: 17.5% versus 21.2% for the dextrose and control group, respectively, P = 0.03). From this experiment, we concluded that addition of dextrose during the weaning to estrus interval did not increase litter size, but seems to affect the uniformity in birth weight of the litter.
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