Animal Science Journal

SOARES, Michael J.; ALAM, S. M. Khorshed; KONNO, Toshihiro; HO‐CHEN, Jennifer K.; AIN, Ruparsri

doi: 10.1111/j.1740-0929.2006.00313.xpmid: N/A

ABSTRACT The prolactin gene family represents species‐specific expansions of hormones/cytokines contributing to the regulation of pregnancy‐dependent adaptations. In this review, we discuss the prolactin family expansion in the mouse and rat, its linkage with viviparity and its potential role in regulating adaptations to physiological stressors.

TAKAHASHI, Toru

doi: 10.1111/j.1740-0929.2006.00314.xpmid: N/A

ABSTRACT Bovine placenta produces an array of proteins that are structurally and functionally similar to pituitary prolactin. Bovine placental lactogen (bPL) is a glycoprotein hormone that has lactogenic and somatogenic properties. Purified bPL contains several kinds of isoforms that are created by alternative splicing and/or multiple glycosylation patterns. bPL can activate the prolactin (PRL) receptor‐mediated signaling pathway as well as PRL does. The bPL mRNA is transcribed in trophoblast binucleate cells, and synthesized bPL protein is stored in membrane‐bound secretory granules. The message encoding bPL is first detectable in trophoblast binucleate cells at approximately day 20 of gestation at, or shortly after, the appearance of binucleate cells in the trophoblast. Most binucleate cells are detected as expressed bPL in the placenta. Bovine PL may be the determinant in trophoblast differentiation. Although the biological activities of bPL have long been studied, the precise role of bPL is still largely unclear. This article reviews and discusses the biological roles of bPL, focusing on luteal function, fetal growth and pregnancy‐associated maternal adaptation, mammogenesis and lactogenesis, and placental angiogenesis. The precise biological function of bPL needs to be further evaluated.

USHIZAWA, Koichi; HASHIZUME, Kazuyoshi

doi: 10.1111/j.1740-0929.2006.00315.xpmid: N/A

ABSTRACT The placenta produces various peptides and steroid hormones that regulate placental function and fetal growth. Prolactin‐related proteins are peptides that are produced by the placenta and belong to the growth hormone/prolactin family, and have structural similarity to prolactin and placental lactogen. Although several prolactin‐related protein genes have been detected in bovine placenta, their expression profiles and functions are not clear. The main difficulties in examining their biological function is the similarity between their genes and the lack of information about their proteins. Recently, molecular biology methods have been used to detect some new bovine prolactin‐related proteins, and elucidate their biological functions. This review focuses on the structures, expression profiles and conceivable functions of prolactin‐related proteins in bovine placenta. With respect to their expression profiles, bovine prolactin‐related proteins fall into four groups: (i) those expressed around the implantation period; (ii) those that reach peak expression in the middle of gestation; (iii) those that increase with the progress of gestation, reaching a peak in late gestation; and (iv) those that reach a plateau in early gestation and are maintained at that level throughout gestation. Data indicate that bovine prolactin‐related proteins have different biological roles in different periods of gestation. In situ monitoring suggests that bovine prolactin‐related protein‐I has a role in the attachment of trophoblast cells to endometrium during the early implantation period.

FUJII, Chie; SUZUKI, Mitsuyoshi

doi: 10.1111/j.1740-0929.2006.00316.xpmid: N/A

ABSTRACT Using a large‐scale data set that included first lactation test day records from 1975 to 2000 for Japanese Holsteins, genetic parameters for milk yield were estimated by using random regression (RR) test‐day models (TDM) with heterogeneous and homogeneous residual variances. It is necessary for the RR‐TDM to include a function that explains the shape of the lactation curve. The RR‐TDM with the LW curve, which combined Wilmink's curve and a Legendre polynomial, was used for fitting the model for milk yield. In recent years, increases in residual variance have been noted for Japanese dairy cattle. Thus, three kinds of heterogeneous residual variance over the calving year were considered: H1, H2 and HG. Linear and quadratic exponential functions for the calving year were used in H1 and H2, respectively. Residual variance of HG was divided into five groups according to calving year. Homogeneous residual variance was HO. All heterogeneous residual variances increased with calving year in an almost linear fashion. Residual variance increased over the study period. However, there is no need to consider heterogeneous residual variances in genetic evaluations, because the heterogeneity of residual variance over the years did not affect the ranking of top sires and cows.

GRAPHODATSKAYA, Daria; JOERG, Hannes; ASAI‐COAKWELL, Mika; JANETT, Fredi; STRANZINGER, Gerald

doi: 10.1111/j.1740-0929.2006.00317.xpmid: N/A

ABSTRACT Agouti signaling protein (ASIP) is involved in the regulation of pigmentation in mammals by downregulating melanocortin 1 receptor (MC1R) activity. In wild type mice, ASIP is expressed in skin and testes. Widespread tissue expression of ASIP has been found in humans and cattle. Reverse transcription with subsequent real‐time polymerase chain reaction was used to measure ASIP expression levels in skin and five additional tissues from four cattle breeds. The expression of each sample was represented as a percentage of the expression of the housekeeping gene b‐actin. No significant difference was found in the expression levels in skin from Red Holstein, Simmental (red), Holstein (black) and Brown Swiss (brown/gray) breeds, which were all in the range of 0.2–0.3%. Expression in other tissues varied greatly between individuals, ranging from 196% in the heart of a Red Holstein animal to 0% in the liver samples of all four breeds. Additionally, we showed that expression of bovine ASIP in cell culture reduces cyclic adenosine monophosphate production in cells expressing MC1R, suggesting that bovine agouti is able to downregulate MC1R signaling.

SASAZAKI, Shinji; HINENOYA, Tomoko; FUJIMA, Daisuke; KIKUCHI, Shinichi; FUJIWARA, Akira; MANNEN, Hideyuki

doi: 10.1111/j.1740-0929.2006.00318.xpmid: N/A

ABSTRACT In our previous study, a Kobe‐NIBS Japanese quail (KNQ) linkage map was constructed mainly using amplified fragment length polymorphism (AFLP) markers. In order to compare chicken and quail chromosomes, we developed expressed sequence tag (EST) markers derived from cDNA‐AFLP fragments and localized these markers on the linkage map. Using a total of 128 AFLP primer combinations, 24 polymorphic bands were obtained between a neurofilament‐deficient mutant quail line male and a muscular disorder quail line female, which were the parents of the KNQ resource family. Nine of the 24 markers were mapped by linkage analysis. These markers were mapped to seven linkage groups, namely 1, 2, 3, 6, 8, 15 and 42. A subsequent homology search using chicken genome sequences strongly suggests that these linkage groups correspond with chicken chromosomes 1, 2, 3, 5, 15, 23 and 26.

NONAKA, Sumie; HASHIZUME, Tsutomu; YAMASHITA, Tetsuro

doi: 10.1111/j.1740-0929.2006.00319.xpmid: N/A

ABSTRACT The present study was carried out to determine whether leptin or leptin (116–130) peptide amide (lep (116–130)), an active fragment of the native protein in rats, is able to stimulate the release of luteinizing hormone (LH), growth hormone (GH) or prolactin (PRL) from cultured porcine anterior pituitary (AP) cells in vitro. The AP cells were obtained from 6 month‐old pigs and were incubated for 3 h with 10−11−10−7 mol/L leptin or lep (116–130) after being cultured in Dulbecco's modified Eagle's medium for 3–4 days. Leptin significantly increased the concentration of LH and GH in the culture medium at concentrations of 10−8 and 10−7 mol/L, respectively, compared with the controls (P < 0.05). Leptin did not increase the concentration of PRL in the culture medium. In contrast to these results, no effects of lep (116–130) on the release of LH, GH or PRL were seen in the cultured cells. These results suggest that leptin stimulates the release of LH and GH by acting directly on porcine AP cells, and that a fragment of leptin protein comprising amino acids 116–130 is not associated with the secretion of hormones in pigs.

MAZUMDER, Md. Arifur Rahman; KUMAGAI, Hajime

doi: 10.1111/j.1740-0929.2006.00320.xpmid: N/A

ABSTRACT An experiment was conducted to analyze feed, climate and animal factors affecting dry matter intake (DMI) in lactating dairy cows. Sixteen lactating Holstein cows, with parity from 1 to 6, were assigned to a feeding trial for 2 years, comprising 31 lactations. The animals were fed Italian ryegrass silage, oat hay, alfalfa hay, beet pulp and three types of concentrate. The data, pooled and classified by stage of lactation, season of lactation and parity were analyzed by stepwise multiple regression to determine the nature and extent of factors affecting DMI. A total of 45 prediction equations for DMI were derived. Energy‐corrected milk yield or milk yield was selected as the primary factor of DMI in all the equations in which the ratio of contribution (R2) varied from 0.26 to 0.67. The dietary concentration of organic cell wall, crude fiber, crude protein, organic b fraction, forage to concentrate ratio, average ambient temperature and temperature–humidity index were selected as the secondary factors affecting DMI for pooled data, late lactation (251–350 days of lactation), summer (June–August), spring (March–May), ≥4th lactation, autumn (September–November) and 3rd lactation, respectively, and improved R2 up to 0.77. Except for an impact of bodyweight in several equations, feed and climatic factors significantly improved prediction equations effectively for data classified in different ways. To estimate DMI accurately in lactating dairy cows, feed and climatic factors should be considered for specific conditions.

KAMIYA, Yuko; KAMIYA, Mitsuru; TANAKA, Masahito

doi: 10.1111/j.1740-0929.2006.00321.xpmid: N/A

ABSTRACT The objective of this experiment was to study the effect of prepartum diets on dry matter intake (DMI) around parturition and on milk production in early lactation during a hot summer. Nine cows due to calve in July or August were assigned to two groups and fed either control (group C; four cows) or high‐concentrate (group H; five cows) diets to meet 110% of their energy requirements from 18 days before the expected calving date to parturition. The proportion of concentrate in the control diet was 35%, and that in the high‐concentrate diet was 45%. For 21 days after parturition, all cows were fed the same diets for lactation ad libitum. The DMI of cows in group H almost met their energy requirements. In group C, the DMI was decreased relative to group H and the concentration of plasma non‐esterified fatty acids was significantly higher (P < 0.05) before parturition. Therefore, the cows in group C were thought to be energy deficient before parturition. After parturition, there were no significant differences in DMI between the two groups. The milk yield of cows in group H tended to be higher than that of cows in group C at 21 days after parturition. Milk protein yield was significantly higher (P < 0.05) in group H 21 days after parturition relative to group C. There were no significant differences in milk composition between the two groups.

IYEGHE‐ERAKPOTOBOR, Grace Takpejewho

doi: 10.1111/j.1740-0929.2006.00322.xpmid: N/A

ABSTRACT The performance of growing crossbred rabbits fed concentrate and Stylosanthes hamata (stylo) at different ratios was evaluated. The following ratios were used: 25:100, 50:75, 75:50, 100:25 and 125:10 (g : g; weight supplied per day). Total weight gain was lower and the feed : gain ratio (FGR) was higher with the 25:100 combination than with the other combinations. Daily feed intake significantly (P < 0.01) decreased, whereas feed cost and cost per kg intake increased as the concentrate level increased. Cost per kg gain increased with increases in concentrate levels up to 100 g before decreasing at 125 g. Weight gain, cost per kg intake and cost per kg gain had a quadratic relationship with concentrate level, whereas FGR and feed cost had a linear relationship. Time required to attain a market weight of 2.5 kg and total feed required to attain market weight decreased, whereas total cost of feeding increased with increases in concentrate level. Dry matter and ash digestibility were similar for all the treatments. Ether extract digestibility was lower for the 25:100 combination compared with the other treatments. Crude protein, nitrogen‐free extract digestibility and nitrogen retention were significantly lower for the 25:100 combination (0.74, 0.66 and 0.64) compared with the 100:25 combination (0.83, 0.75 and 0.79). The dressing percentage was similar for all treatments, whereas the proportion of live weight represented by the head increased with an increase in concentrate level. This study shows that rabbits are able to utilize leaf protein in stylo for growth even at the lowest level of concentrate.