Effects of dietary energy on reproductive function and production in suckled beef cows

Twenty-eight Hereford x Angus cows were utilized to determine the effects of dietary energy level before and after calving on reproductive function and production in suckled beef cows. Low levels of dietary energy before calving resulted in losses of body composition prior to calving, reduced calf birth weight, lengthened intervals from calving to ovulation, and decreased milk production and calf weight at 70 d of age (P\u3c.05). Low levels of dietary energy after calving decreased measures of body composition after calving, reduced the percentage of cows that ovulated following calving, and decreased cow milk production and calf weight at 70 d of age (P\u3c .05). We conclude that dietary energy before and after calving impacts the reproductive function and production of suckled beef cows

Correlações entre medidas determinadas in vivo por ultrassom e na carcaça de ovelhas de descarte

Objetivou-se estudar as medidas de espessura de gordura subcutânea, área de olho-de-lombo, comprimento e profundidade máxima do músculo longissimus dorsi entre a 13ª costela e 1ª vértebra lombar determinadas por ultrassom e na carcaça de ovelhas de descarte abatidas em diferentes estágios fisiológicos, além dos coeficientes de correlação e determinação das medidas avaliadas. Utilizaram-se 21 ovelhas da raça Santa Inês, distribuídas nos seguintes grupos: OL = ovelhas que permaneceram por 60 dias em lactação com seus cordeiros e foram abatidas um dia após o desmame dos mesmos; OSC = ovelhas que permaneceram por 60 dias em lactação com seus cordeiros e mais 30 dias sem os cordeiros e foram posteriormente abatidas; e ONP = ovelhas que não pariram durante o ano. O comprimento máximo do músculo longissimus dorsi obtido pelo ultrassom e na carcaça dos animais não foi influenciado pelos estágios fisiológicos. O ultrassom pode ser utilizado com razoável precisão para estimar características da carcaça de ovelhas de descarte, em particular a espessura de gordura subcutânea.The objective of this paper was to study subcutaneous fat thickness, loin eye area, length and maximum depth measurements of the longissimus dorsi muscle between the 13th rib and the 1st lumbar vertebra determined by ultrasound examination and on the carcass of discard ewes slaughtered in different physiological stages, besides correlation and determination coefficients among measurements evaluated. It was used 21 Santa Ines ewes distributed into the following treatments: EL = ewes that remained in lactation for 60 days with their respective lambs and slaughtered one day after weaning; EWL = ewes that remained in lactation for 60 days with their respective lambs one more period of approximately 30 days without the lambs and slaughtered afterwards; and ENC = ewes that did not give birth during the year. Results showed that the maximum length of the longissimus dorsi muscle obtained by ultrasound examination and on carcass of the animals were not influenced by the experimental treatments. The ultrasound can be used with reasonable accuracy to estimate characteristics of the carcass of discard ewes, particularly the thickness of subcutaneous fat

Feedlot performance and carcass traits of serially slaughtered finishing heifers

Two experiments were conducted at the KSU Agricultural Research Center, Hays, Kansas, to measure feedlot gain and carcass traits of serially slaughtered, yearling crossbred heifers. In Exp. 1, 159 heifers averaging 792 lbs were randomly assigned to one of four slaughter groups, and slaughtered at 21-day intervals beginning at 92 days on feed. In Exp. 2, 181 heifers averaging 759 lbs were randomly assigned to one of four slaughter groups, and slaughtered at intervals of 19, 23 and 21 day, respectively, starting at 127 days. In both experiments, final weight, gain, and carcass weight increased with days on feed. Heifers did not gain body weight between 134 and 155 days on feed in Exp. 1, but heifers continued to gain body weight through 190 days on feed in Exp. 2. Despite having a lighter starting weight, final body weights and hot carcass weights were greater for heifers in Exp. 2 than in Exp. 1 because they had more time on feed. Ribeye area increased with time, although the ratio of ribeye area to carcass weight decreased over time. Increases in backfat and kidney, pelvic, and heart fat suggest that carcass gain increases in fat content over time. Yield grade and marbling scores also increased with each successive slaughter group. Quality grade improved with more days on feed in Exp. 1. Carcass quality was, however, hampered by significantly increased carcass maturity in Exp. 2. Although it is not well defined, the greatest increase in carcass fat deposition seemed to occur between 92 and 113 days on feed in Exp. 1, whereas the increases in carcass fat seemed to increase continually between 127 and 188 days on feed in Exp. 2

Comparison of Dectomax and Valbazen on beef cattle carcass traits

The objective of this trial was to determine if types of dewormers affected carcass characteristics. Crossbred steers (n=428) were stratified by weight and ultrasound marbling score and administered either Dectomax (subcutaneous injection) or Valbazen (oral) dewormer. Fecal egg counts indicated that both dewormers cleared internal parasites from the cattle. Carcass data indicated that Dectomax increased fat deposition as measured by 12th rib back fat; kidney, pelvic, and heart fat; and marbling score, when compared with Valbazen. Deworming products may affect carcass traits that are used to value cattle

Effect of castration time on feedlot performance, carcass characteristics, and beef tenderness

Crossbred Angus calves (n=120) were randomly assigned to early-castrated, early-castrated plus implant, and late-castrated treatment groups. After weaning, calves were placed on feed at the Western Kansas Agricultural Research Station in Hays, Kansas, for finishing. On-feed weights and final weights were similar among treatments. During the first 132 days on feed, the steers castrated early and implanted had a lower average daily gain than early- and late-castration treatments. Early castrates tended (P=0.08) to have a lower feed-to-gain ratio for the first 132 days on feed. Hot carcass weight, internal fat, and marbling scores were not affected by treatment. Carcasses from steers castrated late had less backfat, larger ribeye areas, and lesser yield grades (greater cutability) than carcasses from steers castrated early, with or without an implant. Carcasses from steers castrated early and implanted had a greater percentage grading USDA choice (60%) than did carcasses from steers castrated early (45%) or late (41%). Warner-Bratzler shear force and sensory-panel traits were similar for all treatment groups

Performance and carcass characteristics of cull beef cows implanted with growth promotants and fed a high concentrate ration

Open, cull beef cows fed a high concentrate ration for 28 or 56 days and implanted with Finaplix-H®, Synovex-H®, or both had improved gain and feed efficiency compared to controls (nonimplanted cows). Changes in ultrasound-measured backfat (12th rib) of implanted cows and controls were similar in both feeding periods. Marbling, fat color, and tenderness, as measured by Warner-Bratzler shear force, were not improved by feeding cows for 56 days compared to 28 days. However, lean color, dressing percent, and ribeye area were improved by feeding for 56 days. Numerical yield grade was lower (P<.05) in 28-day fed cows. Implanting with Synovex-H or Finaplix-H resulted in leaner carcasses with lower yield grades compared to controls. Ribeye area was increased by using Synovex-H compared to controls and Finaplix- H. These data indicate that the benefits in gain, feed efficiency, and carcass traits from implanting cull cows can be obtained by using either Synovex-H or Finaplix-H alone

Effects of pregnancy in feedlot heifers on performance and carcass characteristics

Sixty-eight, spring-born, yearling heifers were raised, estrous synchronized, artificially inseminated once, and then finished at the Kansas State University Western Kansas Agricultural Research Center at Hays to determine the effects of pregnancy status on feedlot performance and carcass traits. To achieve a common endpoint at slaughter, heifers were allotted to one of two slaughter dates to achieve a backfat measurement of 0.5 inch. Therefore, both open and pregnant heifers were slaughtered at either 105 or 147 days (fetal age averaged 174 days for the pregnant heifers). Initial weight, rate of gain, and final weight were similar between open and pregnant heifers (P>0.36). Dressing percentage and ribeye area were lower (P<0.05) for pregnant than open heifers. Hot carcass weight tended (P=0.13) to be greater for open heifers. No differences between treatment groups were observed for fat thickness, percentage kidney, pelvic, and heart fat, yield grade, marbling score, or maturity score (P>0.16). However, even though only small differences were recorded in carcass weights, yield grades, and quality grades, their impact on carcass value and cattle feeding profits may be important