Biomaterial Database

Effects of ionophore feeding and anthelmintic administration on age and weight at puberty in spring-born beef heifers. 1996

H T Purvis, and J C Whittier

Animal Science Department, University of Missouri, Columbia 65211, USA.

Two hundred eighty-eight heifer calves in two 1-yr replications were used to test the hypothesis that ionophore (ION) feeding, anthelmintic (ANT) administration, or the combination (COMB) would cause heifers to express pubertal estrus at a younger age than control (CONT) heifers. Heifers were assigned randomly within three weight blocks in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. A high-fiber diet was fed for 172 d during yr 1 (Y1) and 199 d during yr 2 (Y2). Monensin sodium (200mg.animal-1.d-1) was fed to ION and COMB treatments and ivermectin (200 micrograms/kg of BW) was given to ANT and COMB groups at weaning and 84 d later. Rate of gain was monitored every 21 d and diet intake was adjusted to obtain equal rates of gain across treatments. Fecal samples were collected from one-third of the heifers in each group and analyzed for internal parasite egg counts every 21 d. Serum progesterone samples taken twice weekly were used to estimate onset of puberty. There was no treatment x year interaction in any parameter measured and the data were pooled across both years. Total weight gain was similar (P > .10) for all treatments. Fecal egg output decreased (P < .01) after initial application of anthelmintic. The ANT, ION, and COMB heifers had greater (P < .05) gain:feed ratios than did CONT (.132, .142, and .148 vs .125 kg for ANT, ION, COMB, and CONT, respectively). Age and weight at puberty were different (P < .05) for ION (425 d, 351.8 kg), COMB (425 d, 349.5 kg), and ANT (424 d, 348.8 kg) compared with CONT (433 d, 362.5 kg). There was no difference (P > .10) in age and weight at puberty between COMB, ION, or ANT heifers. During Y1, but not Y2, there were a greater (P < .05) number of COMB, ION, and ANT heifers pubertal before the breeding season. Additionally, there was a tendency (P = .12) for higher first-service conception in the COMB, ION, and ANT heifers than in the CONT heifers. Final pregnancy rates among treatments were similar (P > .10).

UI	MeSH Term	Description	Entries
D007476	Ionophores	Chemical agents that increase the permeability of biological or artificial lipid membranes to specific ions. Most ionophores are relatively small organic molecules that act as mobile carriers within membranes or coalesce to form ion permeable channels across membranes. Many are antibiotics, and many act as uncoupling agents by short-circuiting the proton gradient across mitochondrial membranes.	Ionophore
D010270	Parasite Egg Count	Determination of parasite eggs in feces.	Count, Parasite Egg,Counts, Parasite Egg,Egg Count, Parasite,Egg Counts, Parasite,Parasite Egg Counts
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011374	Progesterone	The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.	Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D011897	Random Allocation	A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.	Randomization,Allocation, Random
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D005243	Feces	Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.
D005260	Female		Females
D005306	Fertilization	The fusion of a spermatozoon (SPERMATOZOA) with an OVUM thus resulting in the formation of a ZYGOTE.	Conception,Fertilization, Delayed,Fertilization, Polyspermic,Conceptions,Delayed Fertilization,Delayed Fertilizations,Fertilizations,Fertilizations, Delayed,Fertilizations, Polyspermic,Polyspermic Fertilization,Polyspermic Fertilizations