Effects of testicular status and feeding diets containing date palm by-product on the sensory attributes of Omani lamb meat.

The effects of testicular status and diet on the tenderness and flavour intensity of Omani lamb meat were evaluated. Thirty male lambs were divided into three testicular status treatments shortly after birth, entire, castrated or induced to cryptorchidism. The animals were fed a maize and soya bean meal based diet, isocalorically supplemented with either palm fronds or Rhodesgrass hay.

Serum luteinizing hormone, 13,14-dihydro-15-keto-prostaglandin F2alpha and cortisol profiles during postpartum anestrus in Brahman and Angus cows.

Pluriparous suckled Brahman and Angus cows were utilized to evaluate the effect of breed, day after calving and endogenous opioid peptides (EOP) on hormonal profiles during postpartum anestrus. On Days 17 and 34 after calving, blood samples with and without heparin were collected at 15- and 30-min intervals, respectively, for a 7-h period via jugular cannula. Two hours after the start of blood sampling, cows of each breed were administered either 1 mg/kg iv naloxone or saline.

Hypothalamic proopiomelanocortin mRNA levels in suckled or nonsuckled beef cows: A preliminary study.

This study was conducted to determine proopiomelanocortin (POMC) mRNA levels in the preoptic and hypothalamic brain regions of postpartum anestrous cows. An additional objective was to determine if calf suckling influences POMC mRNA concentration in these regions. Twenty cows were randomly assigned to suckled and nonsuckled treatment groups and slaughtered between 30 and 36 days postpartum.

Effect of prepubertal body weight gain and breed on carcass composition at puberty in beef heifers.

Fourteen prepubertal Angus heifers, all of which reached puberty, and 11 Santa Gertrudis (SG) heifers, eight of which reached puberty, were divided into two treatment groups. There was no breed difference in age at puberty for those that reached puberty. Treatment 1 (T1) heifers, fed to gain .

Release of luteinizing hormone after administration of naloxone in pre- and peripuberal heifers.

This study was conducted to investigate regulation of LH release by opioid peptides during puberal development in beef heifers. Fourteen heifers were randomly assigned to receive naloxone (opioid antagonist) i.v.

Cortisol and prolactin concentrations during three different seasons in relocated Brahman and Hereford bulls.

The objective of this study was to evaluate seasonal changes of cortisol and prolactin (PRL) concentrations in Brahman and Hereford bulls moved to locations that differ in geographical and environmental conditions. Postpubertal Hereford bulls from Montana (n = 15) and Nebraska (n = 15) and Brahman bulls from Texas (n = 18) were located in or relocated to Montana, Nebraska or Texas so that each location had 5 Montana Herefords, 5 Nebraska Herefords and 6 Texas Brahman bulls. Blood samples were collected at 20-minute intervals for 8 hours in November (Fall 1), April (Spring) and November (Fall 2) of the next year.

Isolation of DNA from blood.

A rapid, economical method of DNA isolation from blood was developed that yields DNA suitable for Southern analysis and polymerase chain reactions without organic solvent extractions. Bovine DNA was prepared from peripheral leukocytes and nuclei using pronase E digestion and ethanol precipitation. This isolation method readily adapts to multiple samples.

Serum prolactin and growth hormone responses to naloxone and intracerebral ventricle morphine administration in heifers.

These studies examined responses of serum prolactin (PRL) and growth hormone (GH) to opioid agonist and antagonist administration in heifers. To minimize nonspecific and behavioral effects and to facilitate future studies with specific opioid receptor agonists, a cannula was placed within the third cerebral ventricle of the brain of 4- to 10-mo-old heifers to directly access hypothalamic regions involved in the regulation of PRL and GH secretion. Increasing doses of morphine (M) from 2 to 1,500 micrograms injected into the third cerebral ventricle increased (P less than .

Failure of naloxone to stimulate luteinizing hormone secretion during pregnancy and steroid treatment of ovariectomized beef cows.

The response of serum luteinizing hormone (LH) to naloxone, an opiate antagonist, and gonadotropin-releasing hormone (GnRH) was measured in cows in late pregnancy to assess opioid inhibition of LH. Blood samples were collected at 15-min intervals for 7 h. In a Latin Square arrangement, each cow (n = 6) received naloxone (0, 0.

Progesterone concentrations in beef heifers bred at puberty or third estrus.

Peripheral serum progesterone concentrations were evaluated in beef heifers following breeding collected on d 6 +/- 1, 9 +/- 1 collected on d 6 +/- 1, 9 +/- 1 and 12 +/- 1 (estrus = d 0) after the puberal estrus of all heifers and after the third estrus of E3 heifers. Progesterone concentrations were higher (P less than .05) for heifers in E1 compared with heifers in E3 on d 6, 9 and 12 after breeding to a fertile bull.

Pregnancy rates of beef heifers bred either on puberal or third estrus.

The objective of this study was to determine if pregnancy rates (PR) differed between beef heifers bred to fertile bulls on either their puberal (E1, n = 89) or third (E3, n = 67) estrus. Heifers were obtained from two lactations (Manhattan, L1; and Miles City, L2), and the experiment was conducted at Miles City. Heifers were assigned randomly within location to either E1 or E3.